Category Archives: Exercise is medicine

Exercise to Lower Your Risk of Dying (Prematurely) with Type 1 Diabetes

Bob Stewart Jumping (crop)Much of the research on length of life for individuals living with type 1 diabetes is pessimist, which makes a new study released recently a breath of fresh air. Data were collected for the ongoing nationwide, multicenter, Finnish Diabetic Nephropathy (FinnDiane) Study that tracked the death rate of 2,639 study participants for an average of 11.4 ± 3.5 years (1).

In this study, participants’ leisure time physical activity was reported via a self-report questionnaire. Importantly, their physical activity and its intensity, duration, and frequency were examined related to dying from all causes and from cardiovascular events; some of these adults with type 1 diabetes already had diabetic kidney disease.

The researchers also looked at potentially confounding factors like sex, how long people had been diagnosed with type 1 diabetes and how old they were when they got it, as well as physical measures like their systolic blood pressure, triglycerides (blood fats), BMI (body mass index), and HbA1c (a measure of overall blood glucose control over two to three months).

The conclusions of this study came as no surprise to me: exercise is associated with a lower risk of premature death from cardiovascular or any other cause in adults with type 1 diabetes. Overall, 270 people died during the follow-up period, 127 of whom had kidney disease. Only exercise intensity was associated with cardiovascular mortality, with intense activity being best for preventing early death from cardiovascular events. Both how much total physical activity they got and how frequently they exercised were associated with a lower risk of dying from any cause. Prior studies have shown that exercise frequency may also matter in preventing such events, with a higher frequency of physical activity lowering the risk (2).

People with type 2 diabetes have already been shown to have a lower risk of premature death when they are physically active (3); this is also true for the adult population in general (4; 5). However, not as many studies have looked specifically at the association between physical activity and lower mortality risk in adults with type 1 diabetes. Type 1 diabetes has previously been associated with a shorter lifespan in many adults with it, particularly related to endothelial dysfunction and cardiovascular disease (6).

Earlier studies, such as the DCCT, have shown that keeping blood glucose levels in a more normal range can help lower the risk of diabetes-related complications in people with type 1 diabetes. Most deaths in this population are related to either cardiovascular events or kidney failure. Exercise has an innate ability to lower oxidative stress, which has been implicated in the development of many complications, as well as improve endothelial function (6). While regular physical activity is associated with a lower risk of early death in adults with and without type 2 diabetes, this study is one of the first to examine this association in type 1 diabetes.

While the exact amount of exercise needed to lower the risk of cardiovascular events is unknown and not determined by this study, doing any activity is arguably better than remaining sedentary. As in people without diabetes, intense activity likely is even more cardioprotective than moderate or light activity.

However, the exercise in this study was self-reported and only collected at the start of the study, making it is hard to draw definitive conclusions about how much exercise people need to do and how intense it needs to be to reduce the risk of dying.

In conclusion, as confirmed by this latest study, being physically active on a regular basis is critical to living long and well with type 1 diabetes. Remaining sedentary is far worse for your health and your longevity, so go get active!

                                                                                                                                                           

References cited:

  1. Tikkanen-Dolenc H, Waden J, Forsblom C, Harjutsalo V, Thorn LM, Saraheimo M, Elonen N, Tikkanen HO, Groop PH: Physical Activity Reduces Risk of Premature Mortality in Patients With Type 1 Diabetes With and Without Kidney Disease. Diabetes Care 2017;16:dc17-0615
  2. Tikkanen-Dolenc H, Waden J, Forsblom C, Harjutsalo V, Thorn LM, Saraheimo M, Elonen N, Rosengard-Barlund M, Gordin D, Tikkanen HO, Groop PH: Frequent and intensive physical activity reduces risk of cardiovascular events in type 1 diabetes. Diabetologia 2017;60:574-580. doi: 510.1007/s00125-00016-04189-00128. Epub 02016 Dec 00124.
  3. Loprinzi PD, Sng E: The effects of objectively measured sedentary behavior on all-cause mortality in a national sample of adults with diabetes. Prev Med 2016;86:55-57
  4. Biswas A, Oh PI, Faulkner GE, Bajaj RR, Silver MA, Mitchell MS, Alter DA: Sedentary time and its association with risk for disease incidence, mortality, and hospitalization in adults: a systematic review and meta-analysis. Ann Intern Med 2015;162:123-132
  5. Chau JY, Grunseit AC, Chey T, Stamatakis E, Brown WJ, Matthews CE, Bauman AE, van der Ploeg HP: Daily sitting time and all-cause mortality: a meta-analysis. PLoS One 2013;8:e80000
  6. Bertoluci MC, Ce GV, da Silva AM, Wainstein MV, Boff W, Punales M: Endothelial dysfunction as a predictor of cardiovascular disease in type 1 diabetes. World J Diabetes 2015;6:679-692
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Is Sitting the New Smoking?

Sitting

Make no mistake: sitting less time overall is a good idea for myriad health reasons, but is sitting as bad for you as some would suggest? Is it really the new smoking? In 2017 alone, a slew of new research studies has looked at various health detriments associated with prolonged sitting, even in adults who exercise regularly.

For adults with type 2 diabetes, bouts of either light walking or simple resistance activities benefit not only their glycemic responses to meals (1; 2), but also markers of cardiovascular risk. Both types of interrupting activities are associated with reductions in inflammatory lipids, increases in antioxidant capacity of other lipids, and changes in platelet activation (3).

What is good for one may not be as beneficial for all, though. For example, in adults with low levels of frailty, sedentary time is not predictive of mortality, regardless of physical activity level (4). Sitting more if you are already frail likely just increases frailty and mortality risk, which is not surprising. Along the same lines, being less fit matters in how you respond to breaking up sedentary time. Middle-aged adults with low levels of cardiorespiratory fitness gained the most metabolic benefit from breaking prolonged sitting with regular bouts of light walking, which included five minutes of light walking every 30 minutes over a 7-hour research period (5). If you’re already very fit, adding in some light walking breaks during the day is not going to have as much of an effect—again not surprising.

For in adolescents in school, reducing their sitting time (both in total time and length of bouts) has been shown to improve their blood lipid profiles and cognitive function. A “typical” day (65% of the time spent sitting with two sitting bouts >20 minutes) was compared with a simulated “reduced sitting” day (sitting 50% less with no bouts >20 minutes (6). Can teens stand to improve their health this week? Again, it cannot hurt to break up sedentary time, so why not do it? More recess breaks for teens would be good—and for everyone else for that matter.

All is not lost for people with limited mobility or no ability to engage in weight-bearing activities. Including short bouts of arm ergometry (five minutes of upper body work only every 30 minutes) during prolonged sitting attenuates postprandial glycemia (following two separate meals) when done by obese individuals at high risk of developing type 2 diabetes, even though they remain seated (7). People who cannot walk or stand can, therefore, break up their sedentary time in other ways that can also be metabolically beneficial.

As for other health benefits, breaking up sedentary time is associated with a lower risk of certain types of cancer. In a recent meta-analysis, prolonged television viewing, occupational sitting time, and total sitting time were all associated with increased risks of colorectal cancer in adults (8), which is the most common type after breast/prostate and lung cancers. That study reported a dose-response effect as well, suggesting that both prolonged total sitting time and greater total daily sitting time (2 hours) were associated with a significantly higher risk of colorectal cancer.

In summary, even just the most recent evidence is convincing enough that prolonged sitting is bad for you, and many more studies published similar results in prior years. Is sitting as bad as smoking, though? That remains to be proven. However, you really cannot argue with a recent international consensus statement on sedentary time in older people (9). It states, “Sedentary time is a modifiable determinant of poor health, and in older adults, reducing sedentary time may be an important first step in adopting and maintaining a more active lifestyle.” In fact, the best advice may simply be to consider the whole spectrum of physical activity, from sedentary behavior through to structured exercise (10). Putting yourself anywhere onto that spectrum is definitely better than sitting through the rest of your (shortened) life.

                                                                                                                                                            References cited:

 

  1. Larsen RN, Dempsey PC, Dillon F, Grace M, Kingwell BA, Owen N, Dunstan DW: Does the type of activity “break” from prolonged sitting differentially impact on postprandial blood glucose reductions? An exploratory analysis. Appl Physiol Nutr Metab 2017;42:897-900. doi: 810.1139/apnm-2016-0642. Epub 2017 Mar 1124.
  2. Dempsey PC, Larsen RN, Sethi P, Sacre JW, Straznicky NE, Cohen ND, Cerin E, Lambert GW, Owen N, Kingwell BA, Dunstan DW: Benefits for type 2 diabetes of interrupting prolonged sitting with brief bouts of light walking or simple resistance activities. Diabetes Care 2016;39:964-972
  3. Grace MS, Dempsey PC, Sethi P, Mundra PA, Mellett NA, Weir JM, Owen N, Dunstan DW, Meikle PJ, Kingwell BA: Breaking Up Prolonged Sitting Alters the Postprandial Plasma Lipidomic Profile of Adults With Type 2 Diabetes. J Clin Endocrinol Metab 2017;102:1991-1999. doi: 1910.1210/jc.2016-3926.
  4. Theou O, Blodgett JM, Godin J, Rockwood K: Association between sedentary time and mortality across levels of frailty. CMAJ 2017;189:E1056-E1064. doi: 1010.1503/cmaj.161034.
  5. McCarthy M, Edwardson CL, Davies MJ, Henson J, Bodicoat DH, Khunti K, Dunstan DW, King JA, Yates T: Fitness Moderates Glycemic Responses to Sitting and Light Activity Breaks. Med Sci Sports Exerc 2017;8:0000000000001338
  6. Penning A, Okely AD, Trost SG, Salmon J, Cliff DP, Batterham M, Howard S, Parrish AM: Acute effects of reducing sitting time in adolescents: a randomized cross-over study. BMC Public Health 2017;17:657. doi: 610.1186/s12889-12017-14660-12886.
  7. McCarthy M, Edwardson CL, Davies MJ, Henson J, Rowlands A, King JA, Bodicoat DH, Khunti K, Yates T: Breaking up sedentary time with seated upper body activity can regulate metabolic health in obese high-risk adults: A randomized crossover trial. Diabetes Obes Metab 2017;23:13016
  8. Ma P, Yao Y, Sun W, Dai S, Zhou C: Daily sedentary time and its association with risk for colorectal cancer in adults: A dose-response meta-analysis of prospective cohort studies. Medicine (Baltimore) 2017;96:e7049. doi: 7010.1097/MD.0000000000007049.
  9. Dogra S, Ashe MC, Biddle SJH, Brown WJ, Buman MP, Chastin S, Gardiner PA, Inoue S, Jefferis BJ, Oka K, Owen N, Sardinha LB, Skelton DA, Sugiyama T, Copeland JL: Sedentary time in older men and women: an international consensus statement and research priorities. Br J Sports Med 2017;19:2016-097209
  10. Dempsey PC, Grace MS, Dunstan DW: Adding exercise or subtracting sitting time for glycaemic control: where do we stand? Diabetologia 2017;60:390-394. doi: 310.1007/s00125-00016-04180-00124. Epub 02016 Dec 00112.

Staying Active with Aging Joints and Diabetes

Using bandsWithout 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!

References:

  1. 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
  2. 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;
  3. Rozental TD, Zurakowski D, Blazar PE: Trigger finger: Prognostic indicators of recurrence following corticosteroid injection. J Bone Joint Surg Am 2008;90:1665-1672
  4. 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
  5. 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

Take Back Your Steps!

ADA stairs pictureIt has long been known that regular physical activity is essential for good health. Even Well over 2,000 years ago, Hippocrates (460-370 BC) noted, “Eating alone will not keep man well; he must also take exercise. For food and exercise work together to produce health.” Why, then, is it so hard for us to embrace this concept of being active now?

The main reason that comes to mind is that doing structured exercise takes time, and we all seem to have too little of that nowadays. The only answer to having limited time is my new motto for everyone: “Take back your steps.”

What do I mean by that? A prime example occurs whenever I attend large conventions that involve escalators vs. stairs. I can’t tell you how many times I have come out of a large lecture hall and seen a long line of people (health care professionals at that) waiting to take the escalator that will allow them to ride up to the next floor—even when the stairs right next to the escalators are completely empty and readily available.

It’s time for all of us to start focusing more on doing “unstructured” activities like taking the stairs and walking more. You can always make time in your day to take a few extra steps here and there, and by the end of the day they can add up to a large number. They can even mostly replace your need to engage in more formal exercise programs for which too many people have excuses to not do regularly.

Sure, it’s still beneficial to get in your 30- to 60-minute bouts of aerobic training, and doing some resistance training every week—even if you just do exercises at home that use your own body weight as resistance—is critical to living long and well (and independently).  Arguably, though, the best thing you can do for your overall health and wellbeing at this point is to simply move more all day long, however you can.

Ask your boss for a standing desk, stand up during phone calls, stand up during meetings instead of sitting down the whole time, get up and walk around at least once an hour (to break up your sedentary time), and do resistance exercises while sitting in your chair or driving in your car. All these things simply involve a slight mental adjustment to make them part of your new activity behaviors.

The joy of taking back your steps is that everyone can do it! (Even if you can’t walk, you can do it metaphorically by being more active doing seated exercises.) Who knows?  You may start a trend among your family, friends, and coworkers. At a minimum, you’ll feel more energetic every day instead of tired all the time.

What are you waiting for? Get up and take back your steps today…and every day for the rest of your long and healthy life!

What Affects How Your Insulin Works?

Delaine Wright (T1D) 1There’s nothing worse than doing everything right (or so you think) and having your blood glucose levels running high inexplicably. The problem may be that many different factors can affect your insulin action (whether it’s insulin your body releases or insulin you inject or pump), and you may or may not be controlling for all of them equally well.

What we do know is that most athletic individuals have lower levels of insulin and require less insulin release for carbohydrate and other food intake, meaning that their bodies are very sensitive to insulin. Having low fasting insulin levels (assuming it is not due to a deficiency) is associated with greater longevity, as demonstrated by the fact that most 100-year-olds without diabetes exhibit this trait. Keeping insulin needs lower also reduces your risk for heart disease, high blood pressure, certain cancers, and more.

So what can you do to keep your insulin action high? Almost any type of physical training can make your insulin work better. Resistance training results in enhancements in your muscle mass, allowing for greater overall glucose uptake. Aerobic training generally does not increase muscle mass as much, but that type of activity can enhance muscular uptake of blood glucose.

The effects of aerobic exercise on insulin action usually start to decline within 1-2 days, however, and regular aerobic activity is essential to keeping it higher. Increasing your overall muscle mass may have a more lasting effect by allowing for greater glucose storage in muscle (an insulin-sensitive tissue) and increasing the total amount of glucose you can dispose of through glycogen storage. Muscles have a limit to how much they can store, and having more muscle mass results in a greater potential storage capacity.

Myriad factors can improve your body’s insulin action and making control blood glucose levels easier with less insulin. Don’t try just adding some or more exercise in. For optimal results, try to improve your body’s insulin action by several of these means as their effects are likely to add together to result in a greater overall effect.

Factors That Can Improve Insulin Action:

  • Regular aerobic and resistance exercise
  • Muscle mass gain
  • Loss of body fat—particularly intra-abdominal (visceral) fat, extra fat stored in the liver, and possibly some of the excess fat in muscles
  • Improved blood glucose control (and avoidance of highs and lows)
  • Reduced levels of circulating triglycerides and free fatty acids (fats in blood)
  • Reduction in low-level, systemic inflammation (with physical activity and antioxidants)
  • More effective leptin action (hormone released by fat), causing reduced food intake
  • Reduction in mental (anxiety, depression) and/or physical (illness, etc.) stressors
  • Control of physical (illness, infections, severe muscle soreness, etc.) stressors
  • Decrease in circulating levels of cortisol (released by physical and mental stressors)
  • Increased testosterone levels in men
  • Intake of more dietary fiber, less trans fat, and fewer highly refined foods
  • Daily consumption of a healthy breakfast
  • Adequate dietary intake of key vitamins and minerals, such as magnesium
  • Lower caffeine intake
  • Adequate sleep (seven to eight hours a night for most adults)
  • Effective treatment of sleep apnea
  • Use of insulin-sensitizing oral medications (like Avandia or Actos)

Are You an Exercise Non-Responder?

Roger Hanney (T1D)When researchers have done studies on adults with type 2 diabetes, although the participants as a whole have a positive average response to exercise training, as many as 15 to 20 percent of type 2 exercisers have been found to be “non-responders” (1). These are individuals who appear to be resistant to the beneficial effects of exercise training of all types because exercise training for them fails to improve their A1C (overall blood glucose control), body fat, body mass index, or other metabolic measures. But are there really exercise non-responders? And, if so, are you one of them?

Some researchers have blamed the exercise “non-response” observed in a minority of research subjects on inheriting bad genes. However, a large part of the data that these scientists used to “prove” their case came from animal research. For example, successive generations of rats have been bred until they had either a very high aerobic capacity or a low one, and the researchers then applied their findings that those animals with a low aerobic capacity don’t gain the same metabolic benefits directly to humans.

People are far from being similar to lab rats, though! We’re much more genetically diverse, and our muscles can improve their aerobic capacity with training, regardless of what genes we inherited from our parents (2). In fact, a recent review of 18 training studies concluded that normal training adaptations to aerobic exercise are possible in adults with type 2 diabetes (3), again suggesting the environment is a more viable explanation for those few who don’t respond like everyone else.

What are these environmental factors? For starters, a big issue with human aerobic training is that not all individuals in exercise studies end up training similarly, despite the good intentions of the researchers. I know from training hundreds of research subjects over the years that many older people don’t push themselves as hard as they could when they’re doing the initial exercise test (especially when riding a cycle that makes their legs hurt), and their training protocol is then set up based on a lower-than-actual maximal capacity. So, they may simply not be doing as much total training or expending as many calories during exercise as others in the study.

Many older adults with diabetes also have joint issues or health problems that limit their ability to exercise, including excess body fat, high blood pressure, or nerve damage in their feet. What’s more, what people eat is seldom controlled well in exercise studies, and taking in excess food can override the benefits of exercise, including limiting how long or high insulin action is elevated and blood glucose control after workouts (4). In other words, it’s entirely possible to negate the effects of the last bout of exercise and diminish its acute (and chronic) metabolic benefits by overfeeding.

Simply being less active during the rest of the day can also impact whether you experience the expected results of doing the training. Not surprisingly, people who are more active all day long and not just during training sessions fare better as far as their metabolic health is concerned, even when exercise training is the same for all participants in a study (5).

Even the medications you take can limit your responses to doing exercise training. The most commonly prescribed medication for type 2 diabetes is metformin, and taking metformin can blunt your normal metabolic response to exercise training (6). Taking statins to lower your blood cholesterol can cause some muscular problems that may limit your ability to exercise, as can some other medications commonly prescribed for other health problems.

Even if it’s not the environment that is holding you back and you do have some genetic traits that may limit your exercise response, that certainly doesn’t mean that you won’t gain a lot of other health benefits—both physical and mental—from being more physically active. There really is no evidence that the potential to response to exercise training is limited if you have type 2 diabetes, type 1 diabetes, prediabetes, or obesity; in fact, even breaking up prolonged sitting time has measurable metabolic benefits for everyone (7). So, get up and go be active doing whatever you enjoy the most—and be as active as you possibly can all day long. Your body will thank you for it!

References Cited:

  • Stephens NA, Sparks LM: Resistance to the beneficial effects of exercise in type 2 diabetes: Are some individuals programmed to fail? J Clin Endocrinol Metab 2015;100(1):43-52
  • Pruchnic R, Katsiaras A, He J, Kelley DE, Winters C, Goodpaster BH: Exercise training increases intramyocellular lipid and oxidative capacity in older adults. Am J Physiol Endocrinol Metab 2004;287:E857-862
  • Wang Y, Simar D, Fiatarone Singh MA: Adaptations to exercise training within skeletal muscle in adults with type 2 diabetes or impaired glucose tolerance: a systematic review. Diabetes Metab Res Rev 2009;25:13-40
  • Hagobian TA, Braun B: Interactions between energy surplus and short-term exercise on glucose and insulin responses in healthy people with induced, mild insulin insensitivity. Metabolism 2006;55:402-408
  • Manthou E, Gill JM, Wright A, Malkova D: Behavioral compensatory adjustments to exercise training in overweight women. Med Sci Sports Exerc. 2010;42(6):1121-8
  • Braun B, Eze P, Stephens BR, et al.: Impact of metformin on peak aerobic capacity. Appl Physiol Nutr Metab 2008;33:61-7
  • Dunstan DW, Kingwell BA, Larsen R, et al.: Breaking Up Prolonged Sitting Reduces Postprandial Glucose and Insulin Responses. Diabetes Care 2012;35:976-983

What You Need to Know about Diabetes and Exercise

Joel Livesey (T1D)Here are important things everyone needs to know about exercise and diabetes:

Many times, exercise can virtually erase your blood glucose mistakes. It acts as an extra dose of insulin by getting the glucose out of your blood and into your muscles without insulin (through an insulin-independent mechanism related to muscle contractions themselves). When you’re not active, your body needs insulin to stimulate that uptake. Being regularly active makes your muscles more sensitive to any insulin in your body as well, so it takes less to get the job done. What better way to help erase a little overeating of carbs (or a slight lack of insulin or insulin resistance) than a moderate dose of exercise?

Exercise doesn’t always make your blood glucose come down, at least not right away. When you do intense exercise, glucose-raising hormones (like adrenaline and glucagon) can actually raise your blood glucose instead, albeit usually only temporarily. This phenomenon is true for people with any type of diabetes and even for anyone without diabetes. However, even if a workout raises it in the short run, over a longer period of time (2-3 hours), the residual effects of the exercise will bring your blood glucose back down while you’re replacing the carbs in your muscles. If you take insulin, be careful to take less than normal to correct a post-workout high or your blood glucose will likely be crashing low a few hours later. If you don’t take insulin, give it some time to come back down or do a cool-down with less intense exercise (like less-than-brisk walking) to help bring it back to normal.

How much muscle you have really makes a big difference to your blood glucose control (see prior blog on this topic). Exercise helps you build and retain your muscle mass, which is the main place you store carbs after you eat them. Almost any type of exercise uses up some of your muscle glycogen stores, but if you don’t exercise regularly, your muscles remain packed with it. There is a maximal amount that fits in muscles, which is why building up your muscle mass helps with being able to handle the carbs you eat more effectively. Your liver stores some glucose as glycogen, but not that much relative to your muscles’ total storage capacity. Being sedentary ensures that no amount of insulin is going to be able stimulate more blood glucose uptake into your muscles. Without regular exercise to use up some of that glycogen, you really have nowhere to store carbs, so your blood glucose goes up and some of the excess gets turned into body fat instead. Doing resistance or heavier aerobic training is critical to maintaining the muscle mass you have and offsetting the effects of getting older as much as possible.

People with naturally lower levels of insulin generally live longer (think of centenarians and elite athletes, both of whom have low insulin levels). Exercise helps you keep your insulin needs low, which makes it easier to either make enough of your own or get by with much smaller doses (resulting in less of a margin for big errors in dosing). Plus, It’s really a lot harder to lose body fat if your insulin levels are high or you take large doses because insulin promotes fat storage from excess blood glucose. Both the last time you exercised and how regularly you’re active have an impact on the insulin sensitivity of your muscles, so aim to exercise as least every other day (although daily is likely better) and keep all those muscle fibers you have by using them regularly.

Diabetes aside, exercise is about the best medicine that there is for so many other health conditions.  Being active is one of the best ways to control emotional stress and to stave off depression—far better than antidepressant medications and with no bad side-effects! What’s more, exercise naturally bestows your body with antioxidant effect, which is why regular exercisers are less likely to develop most types of cancer. They also generally feel and act younger than their chronological age and are less likely to even get a cold if doing moderate amounts of regular exercise.

Finally, there are many different ways to exercise, including standing up more, taking extra steps during the day, fidgeting, and just generally being on the move whenever and wherever possible. Knowing that hopefully takes away all of your excuses for not being more active. If you can’t get in a “planned” workout on any given day, you can certainly add in more steps or other activity all day long instead (or do it in addition to your usual exercise). Every bit of movement you do during the day counts, so fidget away as part of your daily dose of exercise!