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!
- 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
- 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.
- 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
- 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
- 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
- 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
Above you see part of the first page of a new consensus statement that comes from many of the individuals involved with the creation and launch of the new JDRF PEAK Performance Program, aimed at educating both clinicians and people with type 1 diabetes how to manage the complexities of being active. In my opinion, this recently published consensus statement on exercise and type 1 diabetes is long overdue and much needed. I managed to get the American Diabetes Association to let me chair an updated position statement (see my November blog) and include type 1 diabetes in it but, unfortunately, never just one addressing type 1 and exercise alone so this JDRF one fills a huge void.
The past decade has seen a growing number of publications related to diabetes management during exercise in people who have to either inject or pump insulin to stay alive. As you well know, whether insulin is injected or pumped, it is not being delivered where it normally ends up in a body that can release its own insulin, and this altered insulin delivery leads to alterations in hormones and blood glucose management by the liver. Normally, your liver would be able to either release or store glucose to keep your levels constant, but not without these proper hormonal signals.
Consequently, the only way you can keep your blood glucose levels normal (or near normal) with exercise is to take in carbohydrate/food, lower circulating insulin levels, or both during activities. Given that exercise is a huge stressor to normal metabolic control of blood glucose, it can make your diabetes more difficult to manage–even though exercising is generally beneficial for a number of other health reasons. This new consensus statement does an excellent job of covering all of the potential effects of engaging in differing physical activities, along with comprehensive management strategies involving changes in food intake and adjustments in basal and/or bolus insulin dosing. It also points out the many areas that need additional (or even any) research with regard to exercising with type 1 diabetes, either to enhance health or sports performance. Read it now if you haven’t already for some great advice!
(1) Riddell MC, Gallen IW, Smart CE, Taplin CE, Adolfsson P, Lumb AN, Kowalski A, Rabasa-Lhoret R, McCrimmon RJ, Hume C, Annan F, Fournier PA, Graham C, Bode B, Galassetti P, Jones TW, Millán IS, Heise T, Peters AL, Petz A, Laffel LM. Exercise management in type 1 diabetes: a consensus statement, Lancet Diabetes Endocrinol. 2017 Jan 23. pii: S2213-8587(17)30014-1. doi: 10.1016/S2213-8587(17)30014-1. [Epub ahead of print]
I would like to let everyone know about a new position statement that covers all types of diabetes (type 1, type 2, and gestational) and prediabetes and addresses physical activity and exercise. It is based on an extensive review of more than 180 papers covering the latest diabetes research and includes the expertise of leaders in the field of diabetes and exercise from top research institutions in the US, Canada, and Australia.
The most notable recommendation calls for three or more minutes of light activity, such as walking, leg extensions or overhead arm stretches, every 30 minutes during prolonged sedentary activities for improved blood sugar management, particularly for people with type 2 diabetes. Sedentary behavior—awake time that involves prolonged sitting, such as sitting at a desk on the computer, sitting in a meeting or watching TV—has a negative effect on preventing or managing health problems, including diabetes. Studies have shown improved blood sugar management when prolonged sitting is interrupted every 30 minutes—with three minutes or more of standing or light-intensity activities, such as leg lifts or extensions, overhead arm stretches, desk chair swivels, torso twists, side lunges, and walking in place. Physical movement improves blood sugar management in people who have sedentary jobs and in people who are overweight, obese and who have difficulty maintaining blood sugars in a healthy range.
These updated guidelines are intended to ensure everyone continues to physically move around throughout the day – at least every 30 minutes – to improve blood glucose management. This movement should be in addition to regular exercise, as it is highly recommended for people with diabetes to be active.
Since incorporating more daily physical activity can mean different things to different people with diabetes, these guidelines offer excellent suggestions on what to do, why to do it and how to do it safely. It includes various categories of physical activity—aerobic exercise, resistance training, flexibility and balance training, and general lifestyle activity—and the benefits of each for people with diabetes.
Aerobic activity benefits patients with type 2 diabetes by improving blood sugar management, as well as encouraging weight loss and reducing cardiovascular risks. Movement that encourages flexibility and balance are helpful for people with type 2 diabetes, especially older adults. Regular aerobic and resistance training also offer health benefits for people with type 1 diabetes, including improvements in insulin sensitivity, cardiovascular fitness and muscle strength. Women who are at-risk or diagnosed with gestational diabetes are encouraged to incorporate aerobic and resistance exercise into their lives most days of the week. People with prediabetes are urged to combine physical activity and healthy lifestyle changes to delay or prevent a type 2 diabetes diagnosis.
Recommendations and precautions for physical activity and exercise will vary based on a patient’s type of diabetes, age, overall health and the presence of diabetes-related complications. Additionally, specific guidelines are outlined on monitoring blood sugar levels during activity. The statement also suggests positive behavior-change strategies that clinicians can utilize to promote physical activity programs.
(1) Colberg SR, Sigal RJ, Yardley JE, Riddell MC, Dunstan DW, Dempsey PC, Horton ES, Castorino K, Tate DF. Physical Activity/Exercise and Diabetes: A Position Statement of the American Diabetes Association, Diabetes Care, 39(11): 2065-2079, 2016. http://dx.doi.org/10.2337/dc16-1728
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!
- 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
Did you know that your body stores fat from excess calories in places other than fat cells? Both your muscles and your liver store extra fat as you gain excess fat weight (1). More fat storage in your muscles may decrease the removal of glucose from your blood, making muscles more resistant to insulin if you don’t exercise regularly (2; 3). Given that your muscles are responsible for the majority of blood glucose uptake in response to insulin, developing insulin-resistant muscles has a substantial impact on your blood glucose. Regular exercisers, paradoxically, can store more fat in their muscles without experiencing insulin resistance, suggesting that the total amount of fat stored there isn’t the critical component but rather how muscles respond to insulin (4).
The greater release of insulin that results from eating excessive amounts of carbohydrate may cause you to gain body fat because carbohydrates are usually converted into and stored as fat when you’re sedentary. If you store fat just in fat cells (particularly in the ones under the skin), you probably will not have as many health problems compared to putting it elsewhere. For example, storing extra fat in your liver may contribute to low-level inflammation, which can lead to the development of insulin resistance, diabetes, heart disease, and other metabolic disorders. Therefore, your liver (and whether or not it stores excess fat) may prove to be a crucial link between weight gain and the development of insulin resistance (1).
An insulin-resistant liver may lead to elevated blood fats and cholesterol levels that contribute to the development of heart disease. You can compound the problem by with dietary choices that contribute to your liver’s insulin resistance, including foods high in refined carbohydrates and highly processed ones. You can lower inflammation and improve your metabolic health with lifestyle changes, including exercising more (5). In fact, being active and eating more fiber naturally in your diet are likely the two most important changes you can make to lower your risk of all metabolic diseases (6).
You don’t have to lose a lot of weight: losing just ten pounds improves your insulin action, lowers inflammation, enhances good cholesterol and lowers the bad, improves metabolic efficiency, and reduces type 2 diabetes risk. Going on a diet to lose weight, however, is not the best long-term solution to managing your body weight or reducing your diabetes risk.
Why? Dieting does not work for most people. It becomes progressively harder to lose weight the longer you stay on a diet (thus making it harder for you to stay motivated to follow it); consequently, many people give up after a while.
A bigger problem is that you are not likely to keep off any weight that you do lose. More than nine out of ten dieters who have successfully lost weight ultimately regain the pounds they struggled to lose. If you go back to eating the same foods after your diet ends that you ate before, you will typically rebound by taking in excessive calories, particularly in the form of extra fat that quickly returns you to your former weight. In fact, most people gain back even more than they lost, regardless of the diet they followed. A greater percentage of the weight you regain is usually body fat, ultimately making your body fat higher than if you had never lost any weight.
While your body’s set point—or what you normally weigh—can change gradually over your lifetime, it remains the same over the relatively short time frame of a diet, unless you make permanent lifestyle changes. If you maintain high levels of daily physical activity while you’re losing weight, though, that will help you prevent gaining it back later on (7). So, if you have to choose between dieting and being more active to lose weight, always choose motion, even if weight loss is slower with exercise alone.
- Koska J, Stefan N, Permana PA, Weyer C, Sonoda M, Bogardus C, Smith SR, Joanisse DR, Funahashi T, Krakoff J, Bunt JC: Increased fat accumulation in liver may link insulin resistance with subcutaneous abdominal adipocyte enlargement, visceral adiposity, and hypoadiponectinemia in obese individuals. Am J Clin Nutr 2008;87:295-302
- Coen PM, Dube JJ, Amati F, Stefanovic-Racic M, Ferrell RE, Toledo FG, Goodpaster BH: Insulin resistance is associated with higher intramyocellular triglycerides in type I but not type II myocytes concomitant with higher ceramide content. Diabetes 2010;59:80-88
- Coen PM, Goodpaster BH: Role of intramyocelluar lipids in human health. Trends Endocrinol Metab 2012;
- Bergman BC, Butterfield GE, Wolfel EE, Casazza GA, Lopaschuk GD, Brooks GA: Evaluation of exercise and training on muscle lipid metabolism. Am J Physiol 1999;276:E106-117
- Zoppini G, Targher G, Zamboni C, Venturi C, Cacciatori V, Moghetti P, Muggeo M: Effects of moderate-intensity exercise training on plasma biomarkers of inflammation and endothelial dysfunction in older patients with type 2 diabetes. Nutr Metab Cardiovasc Dis 2006;16:543-549
- Herder C, Peltonen M, Koenig W, Sutfels K, Lindstrom J, Martin S, Ilanne-Parikka P, Eriksson JG, Aunola S, Keinanen-Kiukaanniemi S, Valle TT, Uusitupa M, Kolb H, Tuomilehto J: Anti-inflammatory effect of lifestyle changes in the Finnish Diabetes Prevention Study. Diabetologia 2009;52:433-442
- Wang X, Lyles MF, You T, Berry MJ, Rejeski WJ, Nicklas BJ: Weight regain is related to decreases in physical activity during weight loss. Med Sci Sports Exerc 2008;40:1781-1788