Physical Activity Is Not Controversial

Physical activity is a challenging thing for everyone to undertake regularly, and it’s also a hard topic for me to write about year after year. Why? It’s because almost everyone can agree that being active is good for your body, mind, and soul. You may have physical limitations that cross some of your potential exercise choices off your list, but everyone can find something that they can do. Some people get more out of exercise than others, but its side effects are helpful, not harmful. It’s not controversial.

Another reason it’s hard to keep writing about is because it doesn’t change much. Exercise fads come and go, but they’re all essentially some variation of intensity, duration, timing, type, and location. Pilates? Sure, but past tense. Jazzercise? Same. Home-based activities, including body-weight exercises, were forced on many people during the COVID-19 lockdowns. High-intensity interval training and cross-training? More popular currently but with so many variations to choose from that it’s not a one-size-fits-all topic.

This year, low-impact workouts are a newer trend as more people are focusing on holistic health and wellbeing. The truth is that almost any activity has its own set of specific benefits, and I usually recommend almost all of them (and doing a variety).

Over the years I have also noticed that people tend to fixate more on their dietary patterns than on exercising. Why? It’s probably because we all have to eat regularly to stay alive, but you can go for years without being active and it doesn’t kill you—at least not right away. All the diabetes and exercise books I have written over the years absolutely had to include diet because you simply can’t manage your blood glucose effectively without considering what you eat and drink and not just your activities.

Being active also takes more effort than choosing what to eat, preparing or buying it, or just having it delivered to your door ready to consume. Exercising can feel painful and unpleasant, especially when you’re out of shape or live a sedentary lifestyle.

Most people who make a New Year’s resolution to be more active drop out of their new program within 6 months, either from feeling demotivated or getting injured. Injuries—both acute and overuse—tend to happen when you ramp up your exercise volume too quickly or set your intensity too high. And it’s not that fun, so people just stop doing it. Or they go on vacation and get out of their exercise routine or get sick for a while and have trouble starting back up. Or they perceive that it takes too much time and really have a limited vision of what qualifies as physical activity. Excuses abound as to why people aren’t active.

At this point, I think I have written an article about almost every aspect of physical activity and exercise, particularly when related to the topics of diabetes, lifestyle, and health management. I’d love to hear from you all what topics you’d like to read more about. Let me know, and I’ll research them and pass along the information in my next blog!

Happy National Diabetes Awareness Month! Please spread the word about how we can all live healthier lives while we’re blessed to be on this earth.

Dang Those Exercise Lows: What to Do to Avoid Them!

For many people, being afraid of having your blood glucose go too low when you’re active has long been a barrier to getting and staying regularly active. It’s a valid fear since many different factors can increase your risk for hypoglycemia (low blood glucose) associated with physical activity, including what activity you do, how long you do it, and how hard you are working out.

What usually happens when you exercise is that your blood glucose goes down, although there may be times and situations when it goes up instead, at least temporarily. What you may not know is that your blood glucose responses can vary based on when you last ate (1), the time of day you’re active, your biological sex, and how much total activity (intensity and duration) you do (2). Those are a lot of factors to figure out and balance appropriately when you have to take insulin.

The amount of insulin you have “on board” (injected, pumped, or inhaled) during activities impacts how likely you are to go low. When your insulin levels are higher, you use more blood glucose during the activity. This effect is compounded by how doses of insulin are absorbed—the insulin peaks later and lasts longer when you take more rapid-acting insulin (3). What’s more, the blood flow to your skin increases when you’re working out, which can speed up insulin absorption (from where it was injected or pumped), which makes you more likely to get low (4). You want to reduce the doses of insulin you take within two to three hours of exercising or lower your basal rates on your pump around exercise; it also may help to exercise more than three hours after you took any mealtime or correction insulin.

To avoid going low, you may need to eat more, monitor your glucose more frequently, and be more careful when you’re exercising in the heat, as that can speed up glucose use and cause you to go low and get dehydrated more easily. When you try a new or unusual activity, you’re more likely to get low until your body adapts to it (known as a “training effect”). Once you’re more trained, your body can switch to using slightly more fat and less carbohydrate (blood glucose included), which keeps your glucose levels more stable during that activity. Training is very specific, though, and this effect only works on the activity you have adapted to doing.

It is also possible to go low after you work out and not just during the activity. If you use up a lot of the glucose stored in your muscles (glycogen) while active, your body will remain more insulin sensitive for hours to days afterward, which can cause you to get low when you’re not expecting it—like during the middle of the night when it’s really inconvenient and harder to detect and treat quickly. Doing repeated interval workouts or intense resistance training can really use a lot of glycogen and raise your risk of later-onset lows (5). You will likely need to monitor more often after and possibly cut back on your insulin or eat more food (particularly carbohydrates) to prevent them.

Finally, you should know that most people with type 1 diabetes have impaired hormonal responses to going low, meaning that your body releases less of glucose-raising hormones like adrenaline and glucagon that helps your body recover from hypoglycemia. Having a prior low or exercising may make your responses to the next low (or exercise bout) even more blunted, so just be on the lookout for lows that can sneak up on you around times of activity. While it is possible to be active safely and effectively regardless, it may take more vigilance and a period of trial and error to get it right. You’ve got this!

References:

1. Yardley JE. Reassessing the evidence: prandial state dictates glycaemic responses to exercise in individuals with type 1 diabetes to a greater extent than intensity. Diabetologia. Aug 18 2022.  doi: 10.1007/s00125-022-05781-8.

2. Steineck IIK, Ranjan AG, Schmidt S, Norgaard K. Time spent in hypoglycemia is comparable when the same amount of exercise is performed 5 or 2 days weekly: a randomized crossover study in people with type 1 diabetes. BMJ Open Diabetes Res Care. 2021;9(1):e001919.

3. Nosek L, Roggen K, Heinemann L, Gottschalk C, Kaiser M, Arnolds S, et al. Insulin aspart has a shorter duration of action than human insulin over a wide dose-range. Diabetes Obes Metab. 2013;15(1):77-83.

4. Koivisto VA, Felig P. Effects of leg exercise on insulin absorption in diabetic patients. N Engl J Med. 1978;298(2):79-83.

5. Joy NG, Tate DB, Davis SN. Counterregulatory responses to hypoglycemia differ between glimepiride and glyburide in non diabetic individuals. Metabolism. 2015;64(6):729-37.

Is It Better for Physical Activity to Be Continuous or Discontinuous?

Back when I started in exercise physiology, it was generally accepted that doing any aerobic activity continuously would give you greater fitness and health benefits. We compared moderate-intensity aerobic exercise (like walking, jogging, cycling, or swimming) with doing the same activity in shorter (but not necessarily harder) sessions or discontinuously. Until recently, the recommendation has been that people should exercise for at least 10 minutes at a time, and only people with a really limited capacity to be active were recommended to do shorter or discontinuous workout sessions.

Times have changed as we have learned more about different types and intensities of aerobic and other forms of training that can be beneficial, especially when it comes to management of blood glucose levels and overall health (1, 2). For instance, doing high-intensity interval training (HIIT) for half as much total time as a moderate-intensity continuous activity increases aerobic fitness at least as much, if not more, than the continuous one and has a similar impact on fasting insulin levels in adults with type 2 diabetes (3). Of course, not everyone can or wants to do harder intervals, but even doing the same total amount of the same intensity differently—such as doing three separate 10-minute sessions instead of one continuous 30-minute session—has the same impact on blood glucose levels in adults with prediabetes or diabetes (4).

Are there other equally beneficial ways to be active? Recently, a systematic review and meta-analysis with 27 studies (and a total of 635 adult participants) with and without diabetes looked at the impact of doing a single session of continuous aerobic activity versus accumulating the same amount of activity in much shorter bouts over the course of the day (5). Interestingly, they found that doing physical activity “breaks” that were mostly low- or moderate-intensity was more effective than doing a single continuous activity when it came to managing blood glucose after meals, even with no change in post-meal insulin levels. That means it may be possible to manage blood glucose simply by being more active all day long, even in short sessions, which gives people more options for becoming and staying more physically active to benefit their health and diabetes management when they have limited time or a lower capacity to exercise.

We have even learned in the past decade that not sitting for long periods of time can improve how metabolism works. Plenty of studies have now reported on the benefits of breaking up sedentary time with any type of physical movement (even standing), whether you have diabetes or not (6-8). Taking just a short (10-minute) walk after a meal can keep blood glucose levels from rising as much (9) and so can doing 3 minutes of activity every 20 minutes after a meal, and people with higher levels of insulin resistance to start with benefit the most (10).

The 2018 U.S. federal recommendations on physical activity (11) now reflect much of this new knowledge (available online at https://health.gov/sites/default/files/2019-09/Physical_Activity_Guidelines_2nd_edition.pdf). They state that “Adults should move more and sit less throughout the day. Some physical activity is better than none. Adults who sit less and do any amount of moderate-to-vigorous physical activity gain some health benefits.” Of course, the more you do, the more benefits you gain—at least up to a point—and adults can benefit from doing a variety of activities weekly that work on cardiorespiratory fitness, strengthen muscles and joints, increase flexibility, and improve balance and agility. Nonetheless, it may be time to implement a nationwide requirement that everyone get up and start moving after every meal. Just think how much that would improve our collective health!

References:

1.   Wu N, Bredin SSD, Guan Y, Dickinson K, Kim DD, Chua Z, et al. Cardiovascular Health Benefits of Exercise Training in Persons Living with Type 1 Diabetes: A Systematic Review and Meta-Analysis. J Clin Med. 2019;8(2).

2.   Pan B, Ge L, Xun YQ, Chen YJ, Gao CY, Han X, et al. Exercise training modalities in patients with type 2 diabetes mellitus: a systematic review and network meta-analysis. Int J Behav Nutr Phys Act. 2018;15(1):72.

3.   Li J, Cheng W, Ma H. A Comparative Study of Health Efficacy Indicators in Subjects with T2DM Applying Power Cycling to 12 Weeks of Low-Volume High-Intensity Interval Training and Moderate-Intensity Continuous Training. J Diabetes Res. 2022;2022:9273830.

4.   Chang CR, Russell BM, Dempsey PC, Christie HE, Campbell MD, Francois ME. Accumulating Physical Activity in Short or Brief Bouts for Glycemic Control in Adults With Prediabetes and Diabetes. Can J Diabetes. 2020;44(8):759-67.

5.   Zhang X, Zheng C, Ho RST, Miyashita M, Wong SHS. The Effects of Accumulated Versus Continuous Exercise on Postprandial Glycemia, Insulin, and Triglycerides in Adults with or Without Diabetes: A Systematic Review and Meta-Analysis.  Sports Med Open. 2022;8.

6.   Gillen JB, Estafanos S, Williamson E, Hodson N, Malowany JM, Kumbhare D, et al. Interrupting prolonged sitting with repeated chair stands or short walks reduces postprandial insulinemia in healthy adults. J Appl Physiol (1985). 2021;130(1):104-13.

7.   Bailey DP, Maylor BD, Orton CJ, Zakrzewski-Fruer JK. Effects of breaking up prolonged sitting following low and high glycaemic index breakfast consumption on glucose and insulin concentrations. Eur J Appl Physiol. 2017;117(7):1299-307.  

8.   Dempsey PC, Owen N, Yates TE, Kingwell BA, Dunstan DW. Sitting Less and Moving More: Improved Glycaemic Control for Type 2 Diabetes Prevention and Management. Curr Diab Rep. 2016;16(11):114.

9.   Bellini A, Nicolò A, Bazzucchi I, Sacchetti M. Effects of Different Exercise Strategies to Improve Postprandial Glycemia in Healthy Individuals. Med Sci Sports Exerc. 2021;53(7):1334-1344.

10. Dempsey PC, Larsen RN, Winkler EAH, Owen N, Kingwell BA, Dunstan DW. Prolonged uninterrupted sitting elevates postprandial hyperglycaemia proportional to degree of insulin resistance. Diabetes Obes Metab. 2018;20(6):1526-30.

11. Piercy KL, Troiano RP, Ballard RM, Carlson SA, Fulton JE, Galuska DA, et al. The Physical Activity Guidelines for Americans. JAMA. 2018;320(19):2020-8.

Variety Is the Spice of Life—and of Physical Activity

I am a long-time believer in the benefits of cross-training when it comes to physical activity. Cross-training means varying your training mode from day to day: for example, on Monday, Wednesday, and Friday, you may do brisk walking and another aerobic exercise (like cycling, rowing, or swimming) on alternate days or resistance training. Doing a variety of activities not only helps you prevent overuse injuries (1), but also can be more motivating.

Since most of the physical activity guidelines—for people with and without diabetes—revolve around moderate to vigorous aerobic exercise and resistance training, what about doing other intensities of exercise? I often advocate alternating hard and easy training days, along with varying the pace of training even within a single exercise session, for best results, but fitness gains can also vary in both directions when you change up the intensity of activities. But do alternate or low-intensity ones count for cross-training, or are they not intense enough?

Whether or not an activity should count may depend on your goals. If your primary objective is to get more fit, doing anything that is moderate or higher in intensity is likely better for raising your aerobic or muscular fitness—although how well you respond depends in large part on your initial level of fitness (i.e., the lower it is, the more you gain from doing any activity at any intensity). Also keep in mind that training gains are activity-specific, meaning that you may be in great shape for walking or running and no shape at all for swimming or rowing. If your goal is more health-related, such as managing blood glucose or health issues, many lower-intensity or alternate activities may be even more appropriate to do than more intense ones.

Let’s take a closer look at some of these other activities. In this category, I would include a lot of less traditional ones, such as stretching, yoga, tai chi, qigong, and even table tennis.

• Stretching and flexibility exercise:

Everyone loses flexibility with aging, but having diabetes can speed up those losses. Any exercise done to prevent or reverse this trend will help you in countless ways. Simply stretching your calves appears to be helpful in many ways (2). Years ago, we studied the impact of doing stretching with resistance training in adults with type 2 diabetes and found that it can increase the range of motion around a variety of joints (3). A more recent study looked at how calf-stretching may help prevent and treat diabetes-related foot ulcers (4), and who would not want to prevent those if they can? I personally have found that stretching my feet (the plantar fascia in particular) and ankles has really increased my flexibility when trying to touch my toes. Stretching all of your major muscles group is recommended at least 2 to 3 days per week.

• Yoga:

Yoga has been frequently studied, but only recently have the studies on populations with diabetes had a high enough quality to be definitive. The findings are that yoga helps people with diabetes—when it comes to overall blood glucose levels (5) and fasting glucose and body mass index (6), even when compared to other higher-intensity exercise. It can even improve quality of life in this population (7) -and lower oxidative stress (8), which is associated with many diabetes-related health complications. So feel free to yoga away!

• Tai chi or qigong:

The potential benefits of tai chi, a low-intensity activity that involves strength and stretching moves and only low-intensity aerobic training, are vast and include potential improvements in fasting blood glucose, certain blood lipid levels, and BMI (9). In fact, tai chi may be more effective than aerobic training for certain metabolic measures, such as A1C and HDL-cholesterol. In some instances, qigong may be even better than tai chi, but it differs by outcomes (10); however, many health improvements have been noted with this family of activities (11), including better cognition and balance (12). It may just be time to take up one of these activities in your spare time for added health benefits.

• Table tennis:

Not many studies on this sport/activity have been done in people with diabetes, but we did one a while ago. In that one small study, playing table tennis for 30 minutes (against a ball robot) was as beneficial as walking after dinner when it came to measures like heart rate variability and mood, but self-paced walking (on a treadmill) had a slight edge when it came to lowering the spike in blood glucose after eating (13). As table tennis is a popular activity and competitive sport in many countries around the world, its potential health impacts should not be ignored. It may be time to dust off that table in your garage and grab a paddle after all.

Overall, doing a variety of physical activities in a given week is optimal—both for physical (joint/muscle/fitness level) and emotional health. So, try a new activity at any intensity level today, especially one that you find enjoyable.

References:

1.   Bales J, Bales K. Training on a knife’s edge: how to balance triathlon training to prevent overuse injuries. Sports Med Arthrosc Rev. 2012;20(4):214-6.

2.   Medeiros DM, Martini TF. Chronic effect of different types of stretching on ankle dorsiflexion range of motion: Systematic review and meta-analysis. Foot. 2018;34:28-35.

3.   Herriott MT, Colberg SR, Parson HK, Nunnold T, Vinik AI. Effects of 8 weeks of flexibility and resistance training in older adults with type 2 diabetes. Diab Care. 2004;27(12):2988-9.

4.   Maeshige N, Uemura M, Hirasawa Y, Yoshikawa Y, Moriguchi M, Kawabe N, et al. Immediate Effects of Weight-Bearing Calf Stretching on Ankle Dorsiflexion Range of Motion and Plantar Pressure During Gait in Patients with Diabetes Mellitus. Int J Low Extrem Wounds. 2021:15347346211031318.

5.   Gupta U, Gupta Y, Jose D, Mani K, Jyotsna VP, Sharma G, et al. Effectiveness of Yoga-based Exercise Program Compared to Usual Care, in Improving HbA1c in Individuals with Type 2 Diabetes: A Randomized Control Trial. Int J Yoga. 2020;13(3):233-8.

6.   Jayawardena R, Ranasinghe P, Chathuranga T, Atapattu PM, Misra A. The benefits of yoga practice compared to physical exercise in the management of type 2 Diabetes Mellitus: A systematic review and meta-analysis. Diab Metab Syndr. 2018;12(5):795-805.

7.   Cui J, Yan JH, Yan LM, Pan L, Le JJ, Guo YZ. Effects of yoga in adults with type 2 diabetes mellitus: A meta-analysis. J Diabetes Investig. 2017;8(2):201-9.

8.   Venugopal V, Geethanjali S, Poonguzhali S, Padmavathi R, Mahadevan S, Silambanan S, et al. Effect of Yoga on oxidative stress in type 2 diabetes mellitus: a systematic review and meta-analysis.  Curr Diabetes Rev. 2021 Apr 4. doi: 10.2174/1573399817666210405104335.

9.   Guo S, Xu Y, Qin J, Chen Y, You Y, Tao J, et al. Effect of tai chi on glycaemic control, lipid metabolism and body composition in adults with type 2 diabetes: A meta-analysis and systematic review. J Rehabil Med. 2021;53(3):jrm00165.

10. Li X, Si H, Chen Y, Li S, Yin N, Wang Z. Effects of fitness qigong and tai chi on middle-aged and elderly patients with type 2 diabetes mellitus. PLoS One. 2020;15(12):e0243989.

11. Zhang YP, Hu RX, Han M, Lai BY, Liang SB, Chen BJ, et al. Evidence Base of Clinical Studies on Qi Gong: A Bibliometric Analysis. Complement Ther Med. 2020;50:102392.

12. Cai H, Li G, Jiang S, Yin H, Liu P, Chen L. Effect of Low-Intensity, Kinect™-Based Kaimai-Style Qigong Exercise in Older Adults With Type 2 Diabetes. J Gerontol Nurs. 2019;45(2):42-52.

13. Colberg SR, Grieco CR, Somma CT. Exercise effects on postprandial glycemia, mood, and sympathovagal balance in type 2 diabetes. J Am Med Dir Assoc. 2014;15(4):261-6.

Starting Out the New Year and Getting Rid of Type 2 Diabetes?

I recently was asked about the latest research on the reversal of type 2 diabetes—both bariatric and non-bariatric solutions—and it made me wonder about the mechanisms of this possibility and what role being active may play in it. Each new year always brings a whole host of resolutions that people make focused on losing weight, getting more fit, and becoming healthier. Especially with all the COVID-related pounds I have heard about people gaining (1), I expect these resolutions to be out in full force at the start of 2022. But how effective will they be long-term, and is the reversal of type 2 diabetes a realistic resolution to make?

Getting blood glucose levels back to normal (to the point where it appears you no longer have type 2 diabetes) may be possible for many, but we also know that hyperglycemia can return if this “reversal” was accomplished through lifestyle improvements when people backslide into less favorable lifestyle habits. Complete remission may be harder to accomplish in people who have had type 2 diabetes for longer as they can permanently lose some of the insulin-making capacity of their pancreatic beta cells (2).

Research on diabetes reversal relying on bariatric surgery has been somewhat more optimistic, and bariatric surgery is now considered the most effective way to improve glycemic management and achieve diabetes remission long-term (3, 4). That said, pre- and post-operative lifestyle changes including regular physical activity are always recommended. Aerobic exercise training following surgery may further enhance weight maintenance, glycemic management, and insulin sensitivity (5-7), and resistance exercise done post-surgery may reverse muscle strength deficits frequently observed after bariatric surgery (8) and help prevent some bone loss  (9, 10).    

As for the reversal of type 2 diabetes without surgery, interventions appear to be focused on weight loss. In a recent study on remission of type 2 diabetes (the DiRECT study), adults ages 20 to 65 who had been diagnosed within the prior six years and not taking insulin followed a 12-month intervention that involved extensive dietary changes but not physical activity (11). In that trial, almost half of participants achieved remission (normal blood glucose and not taking any diabetes medications), with no remission among those who gained weight and the greatest success rate among those who lost the most (86% remission in the participants who lost 15 kg or more). In a two-year follow-up, remission was sustained for more than a third of them, with a remission rate of 64% among those who maintained at least a 10-kg weight loss (12). In my opinion, that is still not that great, especially since most of the success appeared to rely on being able to keep the lost weight off (and we all know how hard that is).

That brings me back to physical activity and its potential role. It appears that remission of type 2 diabetes—at least in those with a more recent onset—is most closely tied to abnormal fat deposits in the pancreas and in the liver (13). Here is where physical activity can play a dramatic role. Exercise training improves whole-body insulin sensitivity but, even more importantly, even just two weeks of exercise training improves beta-cell function in adults with prediabetes and type 2 diabetes and decreases pancreatic fat (14). Substantial weight loss at the time of diabetes diagnosis may work best to prevent loss of pancreatic beta-cell capacity (2), but staying in remission also likely requires maintenance of that lost weight, which we know is more readily accomplished by becoming and remaining physically active (15, 16).

Moreover, both aerobic and resistance training have been shown to reduce ectopic abdominal fat (i.e., visceral, liver, pancreatic, and other abnormal fat deposits) best (14, 17, 18), so why not get and stay more physically active this year? It is the best chance you have for accomplishing your 2022 resolution to get rid of your type 2 diabetes. If getting regularly active is not entirely successful in normalizing your blood glucose levels, at least it will get you closer, and you will have a healthier and happier year and life ahead. Just get up and get moving for the best results.

References:

1. Ruissen MM, Regeer H, Landstra CP, Schroijen M, Jazet I, Nijhoff MF, et al. Increased stress, weight gain and less exercise in relation to glycemic control in people with type 1 and type 2 diabetes during the COVID-19 pandemic. BMJ Open Diabetes Res Care. 2021;9(1).
2. Taylor R, Al-Mrabeh A, Zhyzhneuskaya S, Peters C, Barnes AC, Aribisala BS, et al. Remission of Human Type 2 Diabetes Requires Decrease in Liver and Pancreas Fat Content but Is Dependent upon Capacity for β Cell Recovery. Cell Metab. 2018;28(4):547-56.e3.
3. Mingrone G, Panunzi S, De Gaetano A, Guidone C, Iaconelli A, Capristo E, et al. Metabolic surgery versus conventional medical therapy in patients with type 2 diabetes: 10-year follow-up of an open-label, single-centre, randomised controlled trial Lancet. 2021;397:293-304.
4. Schauer PR, Bhatt DL, Kirwan JP, Wolski K, Aminian A, Brethauer SA, et al. Bariatric Surgery versus Intensive Medical Therapy for Diabetes – 5-Year Outcomes. N Engl J Med. 2017;376(7):641-51.
5. Coen PM, Tanner CJ, Helbling NL, Dubis GS, Hames KC, Xie H, et al. Clinical trial demonstrates exercise following bariatric surgery improves insulin sensitivity. J Clin Invest. 2015;125(1):248-57.
6. Dantas WS, Roschel H, Murai IH, Gil S, Davuluri G, Axelrod CL, et al. Exercise-Induced Increases in Insulin Sensitivity After Bariatric Surgery Are Mediated By Muscle Extracellular Matrix Remodeling. Diabetes. 2020;69(8):1675-91.
7. Mundbjerg LH, Stolberg CR, Cecere S, Bladbjerg EM, Funch-Jensen P, Gram B, et al. Supervised Physical Training Improves Weight Loss After Roux-en-Y Gastric Bypass Surgery: A Randomized Controlled Trial. Obesity (Silver Spring). 2018;26(5):828-37.
8. Oppert JM, Bellicha A, Roda C, Bouillot JL, Torcivia A, Clement K, et al. Resistance Training and Protein Supplementation Increase Strength After Bariatric Surgery: A Randomized Controlled Trial. Obesity (Silver Spring). 2018;26(11):1709-20.
9. Diniz-Sousa F, Veras L, Boppre G, Sa-Couto P, Devezas V, Santos-Sousa H, et al. The Effect of an Exercise Intervention Program on Bone Health After Bariatric Surgery: A Randomized Controlled Trial. J Bone Miner Res. 2021;36(3):489-99.
10. Murai IH, Roschel H, Dantas WS, Gil S, Merege-Filho C, de Cleva R, et al. Exercise Mitigates Bone Loss in Women With Severe Obesity After Roux-en-Y Gastric Bypass: A Randomized Controlled Trial. J Clin Endocrinol Metab. 2019;104(10):4639-50.
11. Lean ME, Leslie WS, Barnes AC, Brosnahan N, Thom G, McCombie L, et al. Primary care-led weight management for remission of type 2 diabetes (DiRECT): an open-label, cluster-randomised trial. Lancet. 2018;391(10120):541-51.
12. Lean MEJ, Leslie WS, Barnes AC, Brosnahan N, Thom G, McCombie L, et al. Durability of a primary care-led weight-management intervention for remission of type 2 diabetes: 2-year results of the DiRECT open-label, cluster-randomised trial. Lancet Diabetes Endocrinol. 2019;7(5):344-55.
13. Petrov MS, Taylor R. Intra-pancreatic fat deposition: bringing hidden fat to the fore. Nat Rev Gastroenterol Hepatol. 2021 Dec 8. (Online ahead of print) PubMed PMID: 34880411.
14. Heiskanen MA, Motiani KK, Mari A, Saunavaara V, Eskelinen JJ, Virtanen KA, et al. Exercise training decreases pancreatic fat content and improves beta cell function regardless of baseline glucose tolerance: a randomised controlled trial. Diabetologia. 2018;61(8):1817-28.
15. Thomas JG, Bond DS, Phelan S, Hill JO, Wing RR. Weight-loss maintenance for 10 years in the National Weight Control Registry. Am J Prev Med. 2014;46(1):17-23.
16. Friedenreich CM, Ruan Y, Duha A, Courneya KS. Exercise Dose Effects on Body Fat 12 Months after an Exercise Intervention: Follow-up from a Randomized Controlled Trial. J Obes. 2019;2019:3916416.
17. Honkala SM, Motiani KK, Eskelinen JJ, Savolainen A, Saunavaara V, Virtanen KA, et al. Exercise Training Reduces Intrathoracic Fat Regardless of Defective Glucose Tolerance. Med Sci Sports Exerc. 2017;49(7):1313-22.
18. Bacchi E, Moghetti P. Exercise for hepatic fat accumulation in type 2 diabetic subjects. Int J Endocrinol. 2013;2013:309191.

Here We Go Again: The Low-Carb vs. High-Carb and Training Debate

Who knew I’d be talking about carbohydrate intake and being active for the third time this year, but here we go again! A lot of confusion still exists related to the practice known as “carb loading” as well.  Do you need to do it? Should you? How do you know?

This controversy keeps coming up because of all the low-carb diet followers out there, especially many people with diabetes. At the American Diabetes Association Scientific Sessions this year (held virtually in June 2021), the MOST popular session of the entire conference was the one I set up to debate low-carb and high-carb eating and athletics (discussed in Diabetes In Control in July) with a virtual meeting record of 3,300 views!

As I commented recently, this debate is still ongoing in active individuals without diabetes. However, some facts are irrefutable, and these can impact the decisions that you make about your dietary plan with diabetes:

• During harder exercise, your active muscles rely almost exclusively on carbohydrate as a fuel. Carbs are converted into energy (ATP) more quickly and with less oxygen required than fat. Carbs acts like high-octane gas while other types give you less energy for the same amount of fuel (and supply it more slowly). You must use carbs to do hard exercise.
• Your body can adapt to a lower carb intake and increase fat use during exercise, at least to a limited extent (see comment above). However, adapting takes weeks and your performance can be negatively impacted if you go low-carb without time to fully adapt.
• While you are in the process of adapting, your training may suffer and you may feel bad during workouts. This may be why many athletes adopt a strategy of periodically doing endurance training with less carb intake but take in unrestricted carbs when competing (i.e., train low-carb and compete high-carb). Following this strategy may help you adapt faster compared to having a low- or a high-carb intake all the time (1).
• Even if you do adapt to lower carbs during training, your body will not necessarily use fewer carbs when active. It may just shift downward the intensity at which you cross over from less carb to more fat use (2). This shift towards greater fat use occurs naturally whenever your muscles start to run out of stored glycogen; the rate of glycogen use appears largely unchanged by low-carb training, however.
• No matter how you eat and train, for intense events sprinting and power lifting, a chronic low-carb intake may be detrimental to your performance if your muscle glycogen stores are low. On the other hand, for endurance activities, you can usually at least maintain how well you perform after adapting to low-carb eating, but chances are your performance may not be better (see first comment above).

When it comes down to it, instead of carb loading, simply varying your carb intake may be as beneficial to performance. For instance, you may want to endurance train with a lower carb intake to increase your ability to oxidize fat, but take in more carbs leading up to any events and during events to maximize your storage. People with diabetes just have to make sure that they are keeping their blood glucose levels in check during any high-carb intake.

If attempting to carb load for even a day (which is usually long enough if you rest or taper) and you take insulin, cover the carbs with enough rapid-acting insulin to keep your blood glucose as near normal as possible to maximize muscle glycogen storage. (Glucose cannot get into muscles cells during rest without insulin.) Most people take in plenty of carbs if they are eating enough overall and even as low as 40 percent of calories from carbs. Effective carb loading does not require you to eat a pasta dinner or massive amounts of starchy foods.

If you take any carbs in during exercise, which most people do during longer events and training even without diabetes, you’ll need very little insulin coverage (if any). If you limit your carb intake afterward, though, you may increase your chances of getting a nighttime low blood glucose, particularly if you use insulin (3). If you do not use insulin, you are unlikely to need any extra carbs during most shorter activities, regardless of how easy or hard you work out. Supplemental carbs are mainly for longer events (90 minutes plus) and for insulin users.

That said, anyone on a low-carb diet may benefit from supplementing with carbs as needed during endurance activities or training (1). Aim for a maximum of 75 grams per hour during prolonged or multi-day activities. During intermittent sports like hockey or soccer, 30 to 60 grams of carbs per hour may prevent fatigue or lows near the end of a game. Keep monitoring your blood glucose, though, as going too high or low can have negative effects on performance.

Primary reference: Colberg SR, Nutrition and exercise performance in adults with type 1 diabetes. Canadian Journal of Diabetes, 44(8):750-758, 2020 (https://doi.org/10.1016/j.jcjd.2020.05.014)

References:

1..  Impey SG, Hearris MA, Hammond KM, Bartlett JD, Louis J, Close GL, et al. Fuel for the Work Required: A Theoretical Framework for Carbohydrate Periodization and the Glycogen Threshold Hypothesis. Sports Medicine. 2018;48(5):1031-48. doi: 10.1007/s40279-018-0867-7. PubMed PMID: 29453741.

2.   Chang CK, Borer K, Lin PJ. Low-Carbohydrate-High-Fat Diet: Can it Help Exercise Performance? J Hum Kinet. 2017;56:81-92.(doi):10.1515/hukin-2017-0025.

3.   Scott SN, Anderson L, Morton JP, Wagenmakers AJM, Riddell MC. Carbohydrate Restriction in Type 1 Diabetes: A Realistic Therapy for Improved Glycaemic Control and Athletic Performance? Nutrients. 2019;11(5):1022. doi: 10.3390/nu11051022. PubMed PMID: 31067747.

Can Diabetes Affect Your Ability to Exercise in Hot Weather?

By Sheri Colberg, PhD

The arrival of summer brings to mind visions of people having fun in the sun and recreating on the beach, but hotter weather also creates greater risks related to dehydration and heat stress for people who are physically active outdoors. Aging by itself negatively affects the body’s ability to dissipate heat in both dry and humid environments (1), but having diabetes further increases the risk of developing heat stress during outdoor activities, especially when it’s hot and/or humid (2). Whole-body heat loss may be impaired due to abnormal skin circulation and decreased sweating (3), both of which can lead to increases in body temperature and heart rate.

People with type 1 diabetes (4) and type 2 diabetes (5) may have impaired regulation of body heat. In particular, athletes with type 1 diabetes may sweat less, especially when they are working out at more intense levels (4), and many adults with type 2 diabetes have a reduced ability to be active in the heat. The good news, though, is that these individuals with diabetes can still acclimate to doing aerobic or resistance training in hotter environments.

What do people need to do to acclimate? Adequate hydration is key to maintaining blood volume and blood flow, both of which affect body cooling during physical activities. Overheating in any environment occurs more easily when dehydrated (6). Dehydration leading to less sweating is more likely when glucose levels are elevated and can lead to chronic hyperglycemia (5). So, everyone needs to closely monitor and manage blood glucose during training or competition in the heat to avoid making any existing impairments in the ability to cool the body worse.

Plain water is usually effective for hydrating during activities lasting an hour or less. During longer workouts or events, water can also suffice for hydration, but sports drinks or other fluids may provide extra carbohydrate to keep blood glucose from dropping too much. In general, consuming about 1 liter of fluid per hour during activities in the heat is recommended (7)—but don’t take in too much or water intoxication can result. Hydrate after activities to restore fluids and electrolytes lost through sweat and breathing (8) and manage blood glucose.

Do the following to minimize the risk of exercise-related heat stress:

• Avoid exercising during the hottest times of the day; choose morning or evening times
• Stay out of direct sunlight during exercise whenever possible
• Wear loose-fitting, light-colored exercise clothing
• Take in extra fluid and electrolytes (e.g., salt) every day while acclimating
• Don’t wait until you’re thirsty to drink fluids, and avoid alcohol since it’s dehydrating
• Give yourself a couple of weeks to fully acclimatize to exercising in the heat
• Try to stay cool until you start exercising, or exercise indoors
• During hot-weather exercise, watch for signs and symptoms of heat-related illness
• If unfit or new to exercise, be extra cautious when working out in the heat

References:

1. Notley SR, Poirier MP, Hardcastle SG, et al. Aging Impairs Whole-Body Heat Loss in Women under Both Dry and Humid Heat Stress. Med Sci Sports Exerc. 2017;49(11):2324-32.
2. Poirier MP, Notley SR, Boulay P, et al. Type 2 diabetes does not exacerbate body heat storage in older adults during brief, extreme passive heat exposure. Temperature. 2020;7(3):263-9.
3. Notley SR, Poirier MP, Sigal RJ, et al. Exercise Heat Stress in Patients with and without Type 2 Diabetes. JAMA. 2019;322(14):1409-11.
4. Carter MR, McGinn R, Barrera-Ramirez J, et al. Impairments in local heat loss in type 1 diabetes during exercise in the heat. Med Sci Sports Exerc. 2014;46(12):2224-33.
5. Kenny GP, Stapleton JM, Yardley JE, et al. Older adults with type 2 diabetes store more heat during exercise. Med Sci Sports Exerc. 2013;45(10):1906-14.
6. Colberg SR. Nutrition and Exercise Performance in Adults with Type 1 Diabetes. Can J Diabetes. 2020;44(8):750-8.
7. Yardley JE, Colberg SR. Update on Management of Type 1 Diabetes and Type 2 Diabetes in Athletes. Curr Sports Med Rep. 2017;16(1):38-44.
8. Evans GH, James LJ, Shirreffs SM, Maughan RJ. Optimizing the restoration and maintenance of fluid balance after exercise-induced dehydration. J Appl Physiol. 2017;122(4):945-51.

Key Exercises and Training for Aging Successfully and Living Your Best Life

As the years have rolled by, nothing has become more clear to me with each passing day than the fact that aging successfully requires a lot of work. When it comes to our bodies, nothing rings truer than “If you don’t use it, you lose it.” This is particularly true when it comes to preventing declines arising from disuse, but also when trying to slow down the normal impacts of aging.

The function of our bodily systems peaks at around age 25 and declines over time. As a result, your maximal aerobic capacity decreases over time, even with constant training, reflective of declines in maximal heart rate. What’s more, your balance ability gets worse (particularly after age 40), bones get thinner, muscles atrophy, reflexes get slower, and recovery from workouts takes longer. Aging is not for sissies (but it beats the alternative)!

The good news is that is it possible to at least slow how rapidly most of these systems decline by changing how you live your life. By including regular physical training, better nutrition, adequate sleep, and stress management, you can delay or prevent a lot of normal aging and reverse decrements caused by inactivity, neglect, disuse, and abuse of our bodies. (The only one we really can’t slow or reverse is our neurological decline.)

It starts to seem like preventing additional declines from inactivity or inadequate training gets to be a full-time job as you get older, and you have to keep adding in additional exercises, stretches, and activities. A fitness instructor recently confirmed that it’s a bit like playing whack-a-mole: fix one weak area or physical problem and another one pops up. Welcome to aging!

So what can you do to live your best life, physically and mentally? I would suggest adding at least these (and many other) critical exercises to your weekly routine:

Cardiorespiratory fitness: Cardio workouts with faster training intervals

In addition to doing regular cardio activities like walking, cycling, and swimming, add in some faster intervals into any workout, such as walking faster for 10 to 60 seconds at a time during your normal walk or doing a hill profile on a cardio training machine. Doing so will increase your fitness more and improve insulin sensitivity for longer. It’s also fine to do high-intensity interval training (HIIT) at least once a week, but start out slowly and progress slowly to prevent injuries and demotivation. Not all your workouts should be equally intense, and varying your aerobic activities also lowers the risk of getting injured.

Muscular strength and endurance: Resistance training exercises

It is easy to work on your muscle strength and muscle endurance by doing a series of resistance exercises targeting your major muscle groups (in the upper body, lower body, and core areas). Pick at least 8 to 10 exercises that cover all these areas and do them at least two to three days per week. It’s fine to use your own body weight, household items (like full water bottles), hand weights, or resistance bands as resistance—you don’t have to have access to a gym or leave home. Adding in these exercises to your weekly routine is critical to aging well and being able to live independently throughout your entire lifespan.

Balance ability: Standing on one leg at a time (and other balance exercises)

This simple exercise involves standing on one leg for a minute, switching to the other leg, and repeating. Have something you can grab onto nearby, such as the back of a chair. You can hold on with both hands, one hand, one finger, or nothing as you get better at balancing. To challenge yourself, move your free leg in different directions (e.g., out front, to the side, behind you) while standing on the other one, or practice standing on uneven surfaces, such as a cushion. If your balance ability is really getting to be an issue, include other balance training activities each week as well.

Joint mobility and cartilage health: Stretches for all your joints

Do a series of flexibility exercises that stretch your joints in all their normal directions to maintain and increase their range of motion. With aging, we are all losing flexibility and diabetes can accelerate this loss when extra glucose sticks to joint surfaces (cartilage) over time and makes them more brittle. Try to stretch at least two to three days per week. The older you get, the longer you should hold each stretch (up to a minute on each one), and you may need to add in specialized stretches (such as for your calves or hips) to really work tighter joints to enhance your mobility and balance ability.

Bone strength: Weight-bearing activities and/or resistance training exercises

Your bones stay stronger when you put normal stress on them regularly, such as carrying your own body weight around when walking or jogging or doing resistance exercises with your upper body or carrying grocery bags. If you stay sedentary, your bones will lose minerals faster and get thinned out more quickly, and non-weight-bearing activities like swimming and cycling just don’t have the ability to build bone as much as weight-bearing ones. Try to adequately stress your bones to stimulate the bone mineral density to stay higher—at least two to three days per week.

Basic mobility and self-care: Wall sits and/or sit-to-stand exercise

Until you start to get older, you seldom think about how difficult it can be to get up out of a chair or off the sofa. Many older people get heavier and weaker and start to have trouble doing these basic maneuvers, which are critical to living well independently. To improve your ability, practice doing wall sits, which involves sitting against a wall with your hips and knees at 90 degree angles and your feet straight below your knees for as long as you can. This exercise will also help prevent knee pain and problems. Alternatively, you can do sit-to-stand exercises where you sit on the edge of an armless chair and practice getting up without using your arms. (This is also often called the “getting up from the toilet” exercise.)

Sexual enjoyment (and incontinence): Kegel exercises

Also known as pelvic floor muscle training, Kegel exercises can help with stress incontinence (i.e., urinating a little when sneezing or laughing) and normal incontinence (both urinary or fecal), and they may enhance your sexual pleasure to boot. The easiest way to identify the pelvic floor muscles is to stop your urine flow while urinating or tighten the muscles that keep you from passing gas. To do Kegels, imagine you are sitting on a marble and pretend you’re lifting it up by tightening your pelvic muscles and holding them contracted for as long as you can; do this a few times in a row. When your muscles get stronger, you can do these exercises while sitting, standing, or walking. Both men and women can and should do Kegel exercises regularly.

Is Weight Loss or Physical Activity More Important for Preventing Type 2 Diabetes?

Ever since the U.S. Diabetes Prevention Program (DPP) multicenter trial was completed nearly two decades ago (1), we have known that it is possible to prevent, or at least delay, prediabetes (an insulin resistant state) from progressing into full-blown type 2 diabetes. Why? Diabetes risk was reduced by 58% in the “intensive lifestyle” (ILS) participant group and by 31% in the metformin (an oral glucose-lowering medication) participants compared to no intervention (“placebo” group). For participants who were 60 years or older, lifestyle changes worked much better to prevent diabetes than taking metformin (1,2).

As an exercise physiologist, what I have always disagreed with about the DPP trial is its greater emphasis on weight loss than on physical activity. Admittedly, ILS consisted of a goal of losing 7 percent of body weight (only 14 pounds if you weight 200) by following a low-calorie, low-fat, high fiber diet and doing at least 150 minutes per week of a moderate physical activity (like brisk walking). In a follow-up report (2), for every kilogram (2.2 pounds) of weight loss, type 2 diabetes risk was reduced by 16%.

However, in the DPP, both a lower percent of calories from fat and increased physical activity predicted weight loss. Typically, it is easier for people to lose some weight than to keep it off afterwards, and that study reported that increased physical activity was critical to maintaining a lower weight. Even among the 495 participants who failed to meet the weight loss goal of 7% loss the first year, those who exercised regularly still had a 44% lower diabetes incidence (without weight loss!), and only the regular exercisers kept the weight off (2). In my mind, that means that physical activity is likely more important.

For the 10-year DPP Outcomes Study (DPPOS) and the 15-year follow-up, all original DPP participants were offered intensive lifestyle management training (3,4). During the first 7 years, diabetes incidence rates decreased by 42% in those who had not been doing ILS or taking metformin previously (DPP placebo group) and by 25% in the DPP metformin participants (who had the option to keep taking metformin); by way of comparison, those in ILS during the DPP increased diabetes rates by 31% during follow-up (5). That seems like a horrible outcome for the DPP ILS participants who only had to keep up their lifestyle changes.

On further analysis, no combination of changes in weight, physical activity, diet, smoking, and antidepressant or statin use explained the DPPOS lower rates of diabetes progression in placebo and metformin groups, but…weight gain was associated with higher rates in the ILS group. That also seems like a bad outcome. Did these participants stop exercising or become less active during the follow-up study? Statistically speaking, physical activity was not a factor that accounted for their increased diabetes rates, but in practical terms, even small changes in activity can make a big difference in blood glucose and body weight management. It’s also important to note that the ILS group still had the overall lowest rates of diabetes incidence at the 15-year mark, even though they rose closer to the other groups (4).

Although the DPP established combined lifestyle improvements (diet, activity, and weight loss) as the best way to prevent type 2 diabetes, a more recent study attempted to determine how much exercise alone contributes, along with the optimal intensity of exercise since most DPP participants did brisk walking (6). Three study groups did varying amounts and intensities of exercise while the fourth followed diet and exercise strategies like the DPP to lose 7% of body weight. Interestingly, a higher amount of moderate-intensity exercise by itself (the equivalent of walking about 13.8 miles weekly) was very effective at improving how well people responded to consuming a large amount of glucose (via an oral glucose tolerance test) despite a relatively modest 2-kilogram (4.4-pound) loss of body fat, which suggests that a higher amount of moderate-intensity walking may work as well as combined approaches for preventing the progression to type 2 diabetes. It should be noted, however, that only the diet and exercise group experienced a decrease in fasting blood glucose levels in that study (6).

So, does physical activity matter? I still maintain that it is as important as—if not more important than—losing weight when it comes to preventing diabetes and managing insulin resistance (even if you have type 1 diabetes), especially since most people have trouble keeping the weight off and only regular physical activity is guaranteed to help you do that. Importantly, the latest follow-up study coming from the DPP just confirmed that I (and others) were right all along (7). In that study, cumulative diabetes incidence remained lower in the lifestyle compared with the placebo and metformin randomized groups and this difference could not be explained by changes in body weight. Examining the self-reported physical activity overall revealed that physical activity was inversely related to diabetes, meaning that the more active people were over time, the less likely they were to develop it, regardless of their body weight. Eureka!

Losing the right type of weight matters as well (that is, mostly fat and not much muscle), so if you are dieting, make sure you include regular activity (particularly resistance exercise) to retain more of your insulin-sensitive muscle mass (8).

References:

1. Knowler WC, Barrett-Connor E, et al. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med. 2002;346(6):393-403.
2. Hamman RF, Wing RR, et al. Effect of weight loss with lifestyle intervention on risk of diabetes. Diabetes Care. 2006;29(9):2102-7.
3. Diabetes Prevention Program Research Group, Knowler WC, et al. 10-year follow-up of diabetes incidence and weight loss in the Diabetes Prevention Program Outcomes Study. Lancet. 2009;374(9702):1677-86.
4. Diabetes Prevention Program Research Group. Long-term effects of lifestyle intervention or metformin on diabetes development and microvascular complications over 15-year follow-up: the Diabetes Prevention Program Outcomes Study. Lancet Diabetes Endocrinol. 2015;3(11):866-75.
5. Diabetes Prevention Program (DPP) Research Group, Hamman RF, et al. Factors affecting the decline in incidence of diabetes in the Diabetes Prevention Program Outcomes Study (DPPOS). Diabetes. 2015;64(3):989-98.
6. Slentz CA, Bateman LA, et al. Effects of exercise training alone vs a combined exercise and nutritional lifestyle intervention on glucose homeostasis in prediabetic individuals: a randomised controlled trial. Diabetologia. 2016;59(10):2088-98.
7. Kriska AM, Rockette-Wagner B, Edelstein SL, et al. The Impact of Physical Activity on the Prevention of Type 2 Diabetes: Evidence and Lessons Learned From the Diabetes Prevention Program, a Long-Standing Clinical Trial Incorporating Subjective and Objective Activity Measures. Diabetes Care. 2021;44(1):43-49.
8. Colleluori G, Aguirre L, et al. Aerobic plus resistance exercise in obese older adults improves muscle protein synthesis and preserves myocellular quality despite weight loss. Cell Metab. 2019;30(2):261-273.e6.

What You Eat and Drink Affects Your Exercise Performance

How well you perform (physically) when you exercise is impacted in a number of ways by the intake of macronutrients—that is, carbohydrate, fat, and protein—whether you have diabetes or not (1, 2). Performance is directly affected by your calorie intake both during an activity and when you are recovering from it. Recovery, by definition, includes the entire time between the end of your last workout or competition and the start of the next one. In many cases, you may need to modify what you eat and drink for different types of training and competition, and periodized (that is, changing over periods of timing for training vs. competition) guidelines can lead you to the appropriate type, amount, and timing of intake of macronutrients and fluids to help you perform optimally (2).

All active people can experience a relative energy imbalance resulting from a mismatch between how many calories they’re consuming and how many they’re using during exercise and recovery. Many nutritional strategies for training and competition may involve pre-event, during-event, and between-event eating to address how to adequately replace calories and fluids. In addition to these and other factors (including muscle and liver glycogen storage and use, hydration, and micronutrient and electrolyte status), individuals with diabetes are additionally impacted by their blood glucose management (see figure).

Exercise carbohydrate requirements depend on an individual’s training status for a given event, as well as on environmental and other factors. When highly trained athletes compete in higher-intensity endurance events lasting up to 3 hours, carbohydrate remains the predominant fuel for the working muscles and its availability becomes rate limiting for performance, not fat availability (3). Anecdotally, according to active insulin users with diabetes, maintenance of their blood glucose levels at more normal levels improves exercise performance (4,5). You may need to adjust both your carbohydrate/food intake and insulin doses to prevent hypoglycemia or hyperglycemia during physical activity (6, 7). Supplementing with carbohydrate remains a proven strategy to increase endurance and intermittent sports performance in individuals without diabetes (8); carbohydrate intake has the greatest impact during activities that would lead to fatigue and/or low blood glucose (9), likely by providing an alternate fuel and sparing glycogen (stored glucose) in select muscle fibers (10). Glucose uptake into active muscles primarily occurs through a contraction-mediated, insulin-independent mechanism during activity, making its use as a fuel possible even if someone is insulin resistant (11).

Although protein use as a fuel during most activities is admittedly minimal, adequate daily intake of protein, mostly during recovery, may also impact overall performance. For most regularly training individuals, daily protein requirements are roughly 1.1 to 1.5 g of protein per kg (2.2 pounds) of body weight (roughly 15% to 20% of total calories) (12). Although aging by itself increases the need for quality protein, its intake is particularly critical in strength training athletes and individuals engaging in long duration aerobic training. If you fail to take in enough daily calories, your protein needs may be increased by exercise, whether or not you have diabetes.

Adapted from Colberg SR, Nutrition and exercise performance in adults with type 1 diabetes. Canadian Journal of Diabetes, 2020 Jun 2:S1499-2671(20)30152-0 (https://doi.org/10.1016/j.jcjd.2020.05.014)

References:

1. Burke LM, Ross ML, Garvican-Lewis LA, Welvaert M, Heikura IA, Forbes SG, et al. Low carbohydrate, high fat diet impairs exercise economy and negates the performance benefit from intensified training in elite race walkers. J Physiol. 2017;595(9):2785-807. doi: 10.1113/JP273230.
2. Burke LM, Castell LM, Casa DJ, Close GL, Costa RJS, Desbrow B, et al. International Association of Athletics Federations Consensus Statement 2019: Nutrition for Athletics. Int J Sport Nutr Exerc Metab. 2019;29(2):73-84. doi: 10.1123/ijsnem.2019-0065.
3. Hawley JA, Leckey JJ. Carbohydrate dependence during prolonged, intense endurance exercise. Sports Med. 2015;45 Suppl 1:S5-12. doi: 10.1007/s40279-015-0400-1.
4. Colberg S. The Athlete’s Guide to Diabetes: Expert Advice for 165 Sports and Activities. Champaign, IL: Human Kinetics; 2020. 382 p.
5. Bally L, Laimer M, Stettler C. Exercise-associated glucose metabolism in individuals with type 1 diabetes mellitus. Curr Opin Clin Nutr Metab Care. 2015;18(4):428-33.  doi: 10.1097/mco.0000000000000185.
6. Campbell MD, Walker M, Bracken RM, Turner D, Stevenson EJ, Gonzalez JT, et al. Insulin therapy and dietary adjustments to normalize glycemia and prevent nocturnal hypoglycemia after evening exercise in type 1 diabetes: a randomized controlled trial. BMJ Open Diabetes Res Care. 2015;3(1):e000085. doi: 10.1136/bmjdrc-2015-000085.
7. Riddell MC, Gallen IW, Smart CE, Taplin CE, Adolfsson P, Lumb AN, et al. Exercise management in type 1 diabetes: a consensus statement. Lancet Diabetes Endocrinol. 2017;5(5):377-90. doi: 10.1016/S2213-8587(17)30014-1.
8. Vandenbogaerde TJ, Hopkins WG. Effects of acute carbohydrate supplementation on endurance performance: a meta-analysis. Sports Med. 2011;41(9):773-92. doi: 10.2165/11590520-000000000-00000.
9. Baker LB, Rollo I, Stein KW, Jeukendrup AE. Acute effects of carbohydrate supplementation on intermittent sports performance. Nutrients. 2015;7(7):5733-63. doi: 10.3390/nu7075249.
10. De Bock K, Derave W, Ramaekers M, Richter EA, Hespel P. Fiber type-specific muscle glycogen sparing due to carbohydrate intake before and during exercise. J Appl Physiol (1985). 2007;102(1):183-8. doi: 10.1152/japplphysiol.00799.2006.
11. Richter EA, Hargreaves M. Exercise, GLUT4, and skeletal muscle glucose uptake. Physiol Rev. 2013;93(3):993-1017. doi: 10.1152/physrev.00038.2012.
12. American Dietetic A, Dietitians of C, American College of Sports M, Rodriguez NR, Di Marco NM, Langley S. American College of Sports Medicine position stand. Nutrition and athletic performance. Med Sci Sports Exerc. 2009;41(3):709-31. doi: 10.1249/MSS.0b013e31890eb86.