Without properly functioning joints, our bodies would be unable to bend, flex, or even move. A joint is wherever two bones come together, held in place by tendons that cross the joint and attach muscles to a bone on the other side and ligaments that attach to bones on both sides of the joint to stabilize it. The ends of the bones are covered with cartilage, a white substance. Specialized cells there called chondrocytes produce large amounts of an extracellular matrix composed of collagen fibers, proteoglycan, elastin fibers, and water. Tendons and ligaments are also made up of primarily of collagen.
Joints can be damaged, however, making movement more difficult or painful. Joint cartilage can be damaged by acute injuries (i.e., ankle sprain, tendon or ligament tears) or overuse (related to repetition of joint movements and wear-and-tear over time). Damage to the thin cartilage layer covering the ends of the bones is not repaired by the body easily or well, mainly because cartilage lacks its own blood supply.
Aging alone can cause you to lose some loss of this articular cartilage layer in knee, hip, and other joints—leading to osteoarthritis and joint pain—but having diabetes also potentially speeds up damage to joints. Although everyone gets stiffer joints with aging, diabetes accelerates the usual loss of flexibility by changing the structure of collagen in the joints, tendons, and ligaments. In short, glucose “sticking” to joint surfaces and collagen makes people with diabetes more prone to overuse injuries like tendinitis and frozen shoulder (1; 2). It may also take longer for their joint injuries to heal properly, especially if blood glucose levels are not managed effectively. What’s more, having reduced motion around joints increases the likelihood of injuries, falls, and self-imposed physical inactivity due to fear of falling.
Reduced flexibility limits movement around joints, increases the likelihood of orthopedic injuries, and presents a greater risk of joint-related problems often associated with diabetes, such as diabetic frozen shoulder, tendinitis, trigger finger, and carpal tunnel syndrome. These joint issues can come on with no warning and for no apparent reason, even if an individual exercises regularly and moderately, and they may recur more easily as well (3). It is not always just due to diabetes, though, since older adults without diabetes experience inflamed joints more readily than when they were younger.
So what can you do to keep your joints mobile if you’re aging (as we all are) and have diabetes? Regular stretching to keep full motion around joints can help prevent some of these problems, and also include specific resistance exercises that strengthen the muscles surrounding affected joints. Vary activities to stress joints differently each day. Overuse injuries occur following excessive use the same joints and muscle in a similar way over an extended period of weeks or months, or they can result from doing too much too soon.
Doing moderate aerobic activity that is weight-bearing (like walking) will actually improve arthritis pain in hips and knees (4). People can also try non-weight-bearing activities, such as aquatic activities that allow joints to be moved more fluidly. Swimming and aquatic classes (like water aerobics) in either shallow or deep water are both appropriate and challenging activities to improve joint mobility, overall strength, and aerobic fitness. Walking in a pool (with or without a flotation belt around the waist), recumbent stationary cycling, upper-body exercises, seated aerobic workouts, and resistance activities will give you additional options to try.
Finally, managing blood glucose levels effectively is also important to limit changed to collagen structures related to hyperglycemia. Losing excess weight and keeping body weight lower will decrease the risk for excessive stress on joints that can lead to lower body joint osteoarthritis (5). Simply staying as active as possible is also critical to allowing your joints to age well, but remember to rest inflamed joints properly to give them a chance to heal properly. You may have to try some new activities as you age to work around your joint limitations, but a side benefit is that you may find some of them to be enjoyable!
- Abate M, Schiavone C, Pelotti P, Salini V: Limited joint mobility in diabetes and ageing: Recent advances in pathogenesis and therapy. Int J Immunopathol Pharmacol 2011;23:997-1003
- Ranger TA, Wong AM, Cook JL, Gaida JE: Is there an association between tendinopathy and diabetes mellitus? A systematic review with meta-analysis. Br J Sports Med 2015;
- Rozental TD, Zurakowski D, Blazar PE: Trigger finger: Prognostic indicators of recurrence following corticosteroid injection. J Bone Joint Surg Am 2008;90:1665-1672
- Rogers LQ, Macera CA, Hootman JM, Ainsworth BE, Blairi SN: The association between joint stress from physical activity and self-reported osteoarthritis: An analysis of the Cooper Clinic data. Osteoarthritis Cartilage 2002;10:617-622
- Magrans-Courtney T, Wilborn C, Rasmussen C, Ferreira M, Greenwood L, Campbell B, Kerksick CM, Nassar E, Li R, Iosia M, Cooke M, Dugan K, Willoughby D, Soliah L, Kreider RB: Effects of diet type and supplementation of glucosamine, chondroitin, and msm on body composition, functional status, and markers of health in women with knee osteoarthritis initiating a resistance-based exercise and weight loss program. J Int Soc Sports Nutr 2011;8:8
For many years, I have focused on aspects of lifestyle and health management that can enhance quality of life, especially when living with diabetes, rather than simply on living a long time (longevity). Much of my motivation is derived from watching my maternal grandmother suffer through six (long) years of severe disability related to cardiovascular complications of diabetes starting at the age of 70 that left her unable to feed herself or communicate, bed bound, and with almost no quality of life for her final six years. Really, what is the point of simply being alive in that case? This topic has come up again recently. New research published online ahead of print in Diabetologia in Spring 2016 (1) presented results showing that the life expectancy and disability-free life expectancy at age 50 years were 30.2 years and 12.7 good years, respectively, for men with diabetes, and 33.9 years and 13.1 good years for women with diabetes.
Really think about what those estimates mean: If you’re female and have diabetes at age 50, you would be expected to live almost to age 84, but likely be disabled in some way from the age of 71 forward. If the disability is severe (as in the case of my stroked-out grandmother), then that is a lot of pointless years of being alive without really living, not to mention being a huge burden to your family.
Admittedly, that’s pretty discouraging. The best solution may be to focus on what we can do to prevent disability with aging rather than simply living longer. Here are three proven ways to improve your quality of life with diabetes (and likely your longevity):
Exercise regularly and be more physically active overall. Even if you already have some diabetes health issues like peripheral neuropathy, which can negatively impact quality of life, exercising regularly can help. In older adults with diabetes and neuropathy, engaging in just 8 weeks of moderate-intensity aerobic exercise improved their quality of life and led to less pain, more feeling in their feet, less restriction in their activities of daily living, better social interactions, and a greater overall life quality—just after 8 weeks of training (2). Other types of physical activity have similar and profound effects on living well with neuropathy (3), so choose what you enjoy doing the most and start with those.
Eat more fiber, found abundantly naturally in plant-based foods. We all know we should be eating more fiber, but where can you find it (besides in Metamucil, which may not have the same health benefits)? Look for it in plant-based foods, mainly fruits, vegetables, grains, beans, and nuts and seeds. Dietary fiber and whole grains contain a unique blend of bioactive components including resistant starches, vitamins, minerals, phytochemicals, and antioxidants, all of which are critical to healthy living. A higher fiber intake helps prevent or protect against health issues that can decrease both quality of life and longevity, including constipation, hemorrhoids, colon cancer, gastric reflux, obesity, diabetes, stroke, and cardiovascular diseases (4). It also keeps the healthful gut bacteria in your digestive tract more abundant, which directly can benefit health and even prevent obesity. Aim for as much as 50 grams of fiber in your daily diet for optimal health.
Improve the quality and quantity of your sleep. Both sleeping better and sleeping enough (7 to 8 hours a night for most adults) lower insulin resistance and can help improve diabetes control; alternately, not getting enough good sleep can make your blood glucose levels much harder to manage. As you age, it may require taking a melatonin supplement to help you fall asleep and improve diabetes control (5), but exercising regularly certainly assists as well, so try taking your daily dose of exercise to optimize sleep. Get started on these three easy changes today to improve your chances for living longer without disabilities. Remember, there’s more to life than living a long time. What’s the point of living longer if you can’t live well and feel your best every day of your life? It really is your choice to make because you can affect the outcome.
- Huo L, et al. “Burden of diabetes in Australia: life expectancy and disability-free life expectancy in adults with diabetes” Diabetologia 2016; DOI: 10.1007/s00125-016-3948-x. 2. Dixit S, Maiya A, Shastry B: Effect of aerobic exercise on quality of life in population with diabetic peripheral neuropathy in type 2 diabetes: a single blind, randomized controlled trial. Quality of Life Research 2014;23:1629-1640
- Streckmann F, Zopf EM, Lehmann HC, May K, Rizza J, Zimmer P, Gollhofer A, Bloch W, Baumann FT: Exercise intervention studies in patients with peripheral neuropathy: a systematic review. Sports Med 2014;44:1289-1304
- Otles S, Ozgoz S: Health effects of dietary fiber. Acta Scientiarum Polonorum Technologia Alimentaria 2014;13:191-202
- Grieco CR, Colberg SR, Somma CT, Thompson A, Vinik AI: Melatonin supplementation lowers oxidative stress and improves glycemic control in type 2 diabetes. International Journal of Diabetes Research, 2(3): 45-49, 2013 (doi: 10.5923/j.diabetes.20130203.02)
A study in Obesity in May 2016 (1) reported very discouraging findings for a group of participants who had lost weight on “The Biggest Loser” (TBL) reality TV show: not only did almost all of them regain a significant amount of weight over the 6-year period afterwards, but they also had lower resting metabolic rates than expected for their body weights, even six years later. With media spin, it won’t be a surprise if everyone just gives up staying thinner and blames excess weight on a faulty, and unchangeable, metabolism.
However, there are a number of factors that impact body weight and weight regain after loss, not just resting metabolism. How much physical activity people do daily and what type, the types of food that people eat, how many calories they actually ingest daily and when they consume them, stress management, and sleep patterns also have an impact on weight maintenance and regain after loss, among other things.
My issues with this study and with TBL’s approach to weight loss are the following:
(1) The way the contestants go about losing large amounts of body weight in a relatively short time is not sustainable as a lifestyle to maintain body weight after loss;
(2) Although TBL participants exercise (a whole lot) during their initial, six-month weight loss period—which helps prevent even greater losses of lean body mass than they would experience otherwise with such extreme weight loss—it does not prevent all muscle mass loss, which means that their total amount of muscle decreased (regardless of their relative ratios of fat and non-fat tissues);
(3) Dietary changes are as important to weight management as they are to weight loss, and diet is de-emphasized on TBL, with a focus instead on reality-TV- and entertainment-driven crazy amounts and types of physical activity; and
(4) TBL approach is not the same as that reported by successful losers and maintainers followed in the National Weight Control Registry (http://www.nwcr.ws).
With regard to that last point, much can be learned from studying members of the National Weight Control Registry (NWCR), which only includes people with medically documented weight losses of at least 30 pounds that were maintained for at least a year. While the members lost and keep the weight off in a variety of ways, most report continuing to maintain a low-calorie, low-fat diet and doing high levels of physical activity. Among the NWCR members: 78% eat breakfast every day; 75% weigh themselves at least once a week; 62% watch less than 10 hours of TV per week; and 90% exercise, on average, about 1 hour per day.
In one study, NWCR subjects spent significantly more time per day in sustained bouts of moderate-to-vigorous physical activity than their overweight counterparts (41.5 ± 35.1 min/day vs. 19.2 ± 18.6 min/day) and marginally more than normal weight adults (25.8 ± 23.4), so they were actually getting more daily exercise than most (2). A 10-year study of self-reported weight loss and behavior change in 2,886 NWCR participants (78% female; mean age 48 years), and more than 87% were still maintaining at least a 10% weight loss after five and ten years (3). Even though decreases in leisure-time physical activity, dietary restraint, and frequency of self-weighing, along with increases in percentage of energy intake from fat and disinhibition, were associated with greater weight regain, the majority of weight lost by NWCR members has been maintained over 10 years.
Others have reported that the differences in total weight gain in people being overfed similar amounts of calories was likely due to the total amount of daily movement that they engaged in, including standing, fidgeting, and taking more steps, not just planned exercise (4). Weight maintenance may, therefore, as influenced by total daily activity that is not necessarily reported or measured like most moderate and vigorous exercise is.
Weight maintenance may also be as simple as staying on top of body weight. NWCR studies have shown that consistent self-weighing may help individuals maintain their successful weight loss by allowing them to catch weight gains before they escalate and make behavior changes to prevent additional weight gain, and decreased self-weighing frequency is independently associated with greater weight regain (5).
Clearly, the body is a complex system with many different bodily and environmental factors adding to the mix. In the TBL study, there was no indication that they controlled for the potential effects of the last bout of exercise on resting metabolic measures (at least this was not reported on in the study), although exercise can impact metabolism for 2-72 hours afterwards They did not measure or report on the types of foods that the “biggest losers” were eating, although fiber is known to improve the gut microbiota and may be related to successful weight loss and maintenance (7). While many reported being active, doing cardio training versus resistance can have differing impacts on muscle glycogen storage, muscle mass, and insulin action, as well as resting metabolism, and the type of activity done was not reported in TBL study.
So, before we jump to any conclusions and blame all weight regain on something completely outside our control (a lower resting metabolism) and relinquish all personal responsibility for weight maintenance, make sure to consider all of the other potentially confounding variables that have not necessarily been well studied at this point. Let’s not just rely on and sensationalize the results of one small pilot study of “biggest losers,’ but rather take away lessons learned from the successful maintainers who are members of the much more reality-based NWCR.
- Fothergill E, Guo J, Howard L, Kerns JC, Knuth ND, Brychta R, Chen KY, Skarulis MC, Walter M, Walter PJ, Hall KD: Persistent metabolic adaptation 6 years after “the biggest loser” competition. Obesity 2016:n/a-n/a
An updated position statement on the dangers of hyponatremia (also known as water intoxication) was just released (1). It once again highlights how drinking too much water or any fluids during physical activity in the hopes of preventing dehydration can be potentially fatal.
Taking in too much fluid dilutes the sodium levels in your blood, and severely low sodium levels can lead to brain swelling, seizures, coma, and death. Less severe, symptoms of hyponatremia include nausea and vomiting, headache, confusion, loss of energy and fatigue, restlessness and irritability, and muscle weakness, spasms or cramps.
Hyponatremia has become a problem in recent years following the push to stay hydrated during all exercise, but until recently has primarily been associated with marathon races and other prolonged endurance events, especially among slow participants. Their main problem is that they don’t sweat that much, but they drink at every opportunity, often to excess over many hours due to fear of getting dehydrated. More recently, though it has been reported as being a problem during half-marathons, sprint triathlons, long hikes, yoga classes, and team sport practices and games, particularly football at all levels.
Drinking sports drinks or other fluids with electrolytes in them instead of straight water can help a little bit, but hyponatremia appears to be more related to your total fluid intake, not whether or not the drinks contain some sodium in them (2). Sports drinks containing added sodium are still more dilute than what’s in your blood, and drinking any fluids in excess during exercise can lower your blood sodium levels.
This condition is almost completely preventable. The key is simply to drink only when you feel thirsty during exercise. It really isn’t necessary to stay ahead of your thirst. The small impact that slight dehydration is going to have on your performance is nothing compared to the medical emergency created by drinking too much. Listening to your “innate thirst mechanism” provides a safe and reliable guide to hydration (1).
Using thirst as your guide should not increase your risk for cramping either since dehydration may only contribute minimally to cramps, which are likely more associated with fatigue than dehydration/electrolyte losses (3). Even becoming severely dehydrated during exercise in the heat is not likely to cause muscle cramps (4).
Surprisingly, becoming dehydrated during exercise will not necessarily increase the risk of developing a heat-related illness like heat stroke either. A body mass loss of up to 3% (mostly fluid losses through sweating) was found to be tolerated by well-trained triathletes during an Ironman competition in warm conditions without any evidence of heat illnesses (5). In fact, athletes who collapse from heat illness often are quite well-hydrated, and it’s more likely that cramping and heat illnesses come from exercising too intensely. Muscles are more prone to spasms when fatigued, and heat illnesses generally occur in people who aren’t used to exercising in the heat and who continue to work out even when feeling unwell.
People with diabetes are also more likely to have electrolyte imbalances (e.g., sodium and potassium) to start with, including hyponatremia associated with extended hyperglycemia (6). As discussed in a recent article (7), an increased risk of electrolyte disturbances with diabetes can result from poorer blood glucose management, diabetes medications (some of which alter electrolyte balance), and organ damage associated with diabetes (such as nephropathy).
When it comes down to it, preventing overhydration during exercise is likely more important that worrying about the effects of dehydration. Use thirst as your guide when you exercise, and avoid consuming excess fluids, especially during prolonged workouts or sporting events. Also, keep your blood glucose levels in better control overall prior to engaging in any activities to ensure that hyponatremia is not an issue.
- Hew-Butler T, Rosner MH, Fowkes-Godek S, et al. Statement of the 3rd International Exercise-Associated Hyponatremia Consensus Development Conference, Carlsbad, California, 2015. Br J Sports Med. 2015 Jul 30. pii: bjsports-2015-095004. doi: 10.1136/bjsports-2015-095004. [Epub ahead of print] (http://www.ncbi.nlm.nih.gov/pubmed/26227507)
- Dugas J. Sodium ingestion and hyponatraemia: sports drinks do not prevent a fall in serum sodium concentration during exercise. Br J Sports Med. 2006 Apr; 40(4): 372. doi: 1136/bjsm.2005.022400 PMCID: PMC2577547 (http://www.ncbi.nlm.nih.gov/pubmed/16556798)
- Miller KC, Mack GW, Knight KL, et al. Three percent hypohydration does not affect threshold frequency of electrically induced cramps. Med Sci Sports Exerc. 2010 Nov;42(11):2056-63. doi: 10.1249/MSS.0b013e3181dd5e3a. (http://www.ncbi.nlm.nih.gov/pubmed/20351595)
- Braulick KW, Miller KC, Albrecht JM, Tucker JM, Deal JE. Significant and serious dehydration does not affect skeletal muscle cramp threshold frequency. Br J Sports Med. 2013 Jul;47(11):710-4. doi: 10.1136/bjsports-2012-091501. (http://www.ncbi.nlm.nih.gov/pubmed/23222192)
- Laursen PB, Suriano R, Quod MJ, et al. Core temperature and hydration status during an Ironman triathlon. Br J Sports Med. 2006 Apr;40(4):320-5; discussion 325. (http://www.ncbi.nlm.nih.gov/pubmed/16556786)
- Palmer BF, Clegg DJ. “Electrolyte and Acid-Base Disturbances in Patients with Diabetes Mellitus.” N Engl J Med. 2015;373(6):548-59. (http://www.ncbi.nlm.nih.gov/pubmed/26244308)
- Beware: Diabetes Results in Significant Electrolyte Disturbances, Diabetes In Control, Issue 798, September 11, 2015 (http://www.diabetesincontrol.com/articles/53-diabetes-news/18464-beware-diabetes-results-in-significant-electrolyte-disturbances#unused)
With all the exercise training fads out there, it can be hard to navigate the landscape with diabetes. I am frequently asked about the latest training techniques or gym trends, so I want to specifically address a recent craze, CrossFit training, with regard to whether it’s appropriate and/or advisable for people with diabetes.
In brief, CrossFit training is a strength and conditioning program consisting mainly of a mix of aerobic exercise, gymnastics (body weight exercises), and Olympic weight lifting. Its programming is decentralized, but its general methodology is used by thousands of private affiliated gyms around the world. CrossFit, Inc., licenses the CrossFit name to gyms for an annual fee and certifies trainers, but the actual programs vary tremendously from site to site.
A concerned young man with type 1 diabetes contacted me to ask whether it’s safe for him to do CrossFit. Although he was already doing and benefiting from CrossFit training, he became concerned about it after reading a blog online by a Paleo diet advocate named Robb Wolf who, in an article about CrossFit training and type 1 diabetes, blogged that since intense training causes the liver to release excess glucose during training, people with type 1 diabetes “may be better served by mild to low intensity activities. Power Lifting, due to the low volume, might be a good option.” (This blogger also claimed that “We have seen instance of people REVERSING type 1 diabetes with a Paleo diet because they put their autoimmunity in remission.” That statement alone should make you question his credibility. If you really want to read it, please just don’t believe everything you read online, especially his blog: http://robbwolf.com/2009/08/05/type-1-diabetes-and-crossfit/#sthash.CIZdVMvp.dpu.)
My perspective is that, if you’re young and healthy and just happen to have diabetes, you should be able to engage in CrossFit training without worrying excessively about your blood glucose levels going up temporarily from doing it. To control your blood glucose, you simply have to approach it like any other intense workout, which can cause your blood glucose to go up even in people without diabetes. If you use insulin, you’ll just need to check your glucose frequently and adjust your insulin doses to make sure you have enough to stay in control both during and following your CrossFit (or other) workouts. As a side note, doing some easy cardio exercise after an intense workout can help lower your blood glucose naturally. Also, keep in mind that you’re more likely to have a bigger rise in the early AM compared to doing the same exact training later in the day (due to having more glucose-raising hormones and less insulin on board in the morning, pre-breakfast).
CrossFit does carry some risks, however. The risk of injury from some of its exercises outweighs their benefits when they are performed with poor form in timed workouts (although there are similar risks from doing other high-intensity programs incorrectly). One concern in particular is that CrossFit’s extensive online community enables anyone to follow the program without proper guidance, increasing the risk of improper form or technique that leads to getting injured. I have heard of at least one young man who caused significant damage to the cartilage in both of his knees doing such training inappropriately. When undertaken correctly, CrossFit is not inherently bad or ineffective, but beginning exercisers starting such a program may be encouraged to do too much and not be able to discern between training to failure and simply getting a good workout.
By way of example, a young woman who was a physical therapist and a regular CrossFit participant woke the morning after a particularly grueling session consisting of hundreds of reps of arm exercises and found she could not bend her elbows. She was diagnosed in the emergency room with rhabdomyolysis (“rhabdo” for short), a condition in which damaged muscles break down rapidly. This is not the first time CrossFit has been associated with rhabdo as the workouts can be particularly grueling and excessive, although any strenuous exercise can cause it. It’s worrisome because rhabdo can lead to kidney failure when excess breakdown products of damaged muscle cells (myoglobin) are released into your blood (see a video by the Mayo Clinic about exercise-associated rhabdo: https://www.youtube.com/watch?v=Hy0uEPo8-7w). Severe symptoms like muscle pain, vomiting, and confusion are symptoms of greater muscle damage and possible kidney failure. If you ever have severe muscle pain and dark colored urine, get medical attention immediately.
The biggest problem most insulin users face is the risk of their blood glucose going too low for up to two days after they exercise. Given that there are no clear recommendations about the best time to exercise with diabetes, a recent study published in the Journal of Diabetes Science and Technology early in 2015 tackled this issue head-on.
The study compared blood glucose levels and the number of lows during and following moderate exercise for 36 hours. A total of 35 adults with type 1 diabetes using insulin pumps undertook 60 minutes of moderate exercise on a treadmill at 7 AM (pre-breakfast) and 4 PM (pre-dinner) on different days. During exercise their insulin pumps were turned off completely and then restarted 45 minutes after they stopped working out. How frequently they developed hypoglycemia (defined as glucose values < 70 mg/dl, or3.9 mmol/l) for up to 36 hours post-workout was monitored using both a continuous glucose monitor (CGM) and normal fingerstick tests.
What do you think they found out? Figure 1 shows when the hypoglycemic events happened. Overall, hypos occurred significantly less often following 7 AM exercise compared to 4 PM (5.6 vs. 10.7 hypos per person). This is not a new finding, however, as other studies done previously in both type 1 and type 2 exercisers have found that you’re more likely to get low from exercise done later in the day.
What was Interesting about this study was that most of the lows occurred 15 to 24 hours after exercise, regardless of the exercise timing, and over half of the adults in the study had at least one low in 36 hours. On days following morning exercise, there were 20% more CGM readings between 70 and 200 mg/dL (3.9 and 11.1 mmol/l) than on the day before they exercised in the morning, meaning that doing pre-breakfast exercise kept their blood glucose levels in a more normal range and improved their overall control, all with a lower risk of hypos.
Details about the 7 AM, pre-breakfast exercise: Participants had 180 lows after the morning sessions (5.6 per participant during 36 hours), with most occurring 15 to 24 hours after the sessions (between 10 PM and 7 AM—just when you don’t want to go low!). When people exercised before breakfast, no one got low during or immediately after the exercise.
Details about the 4 PM, late afternoon exercise: They had 322 hypos after the afternoon sessions (10.7 per participant during 36 hours), with most occurring 15 to 21 hours after exercise, which in this case was between 7 AM to noon. Six people got low during the exercise itself (compared to none during AM exercise).
Not surprisingly, this study reported fewer hypos when insulin users exercise at 7 AM, prior to breakfast and morning rapid-acting insulin. At that time of day, levels of the hormone cortisol are higher, which lowers insulin action and keeps blood glucose levels from dropping, and circulating insulin is lower as well (prior to any insulin taken for breakfast). The afternoon exercise was done at 4 PM, which was four hours after lunch and use of rapid-acting insulin, but the “tail” of any insulin taken during the day may still lead to higher insulin levels overall in the afternoon compared to in the morning.
So, when should you exercise? I still say that the best time to exercise is when you have the time to do it on any given day. However, if you exercise later in the day, you may have to eat more or take less insulin to prevent later-onset hypoglycemia.
One more thing to keep in mind, though, is that this study only tested moderate activity. If you work out harder, your blood glucose is more likely to rise during the activity, which may result in hyperglycemia instead of hypos. In that case, doing intense afternoon activity may be preferable!
If you’re a die-hard morning exerciser but get frustrated with the rise in glucose that comes with it, you can also get around that by simply “breaking” your fast before you exercise, or making your 7 AM bout of activity after you eat something instead of before. If you have type 1, you’ll have to take a small amount of insulin (albeit much less than normal) to cover it, and if you have type 2, your pancreas should release what you need to lower the insulin resistance associated with early mornings. You don’t have to eat a full breakfast to make this work. So, you still have lots of options, but all come with their own issues that you’ll have to figure out to prevent exercise-induced lows.
Gomez, A. M., C. Gomez, P. Aschner, A. Veloza, O. Munoz, C. Rubio & S. Vallejo (2015) Effects of Performing Morning Versus Afternoon Exercise on Glycemic Control and Hypoglycemia Frequency in Type 1 Diabetes Patients on Sensor-Augmented Insulin Pump Therapy. J Diabetes Sci Technol.