A Look at Exercise Response

Are there really exercise non-responders?

sheri complications of diabetesBy Sheri Colberg-Ochs, PhD

When researchers conduct studies on people with type 2 diabetes, although the participants as a whole have a positive 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?

Some researchers have blamed the exercise "non-response" observed on bad genes. However, a large part of the data that these scientists used to "prove" their point came from animal research. Successive generations of rats were bred until they had either a very high aerobic capacity or a low one, and they applied these findings 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 in terms of exercise response? 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. 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 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, diet 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; people who are more active all day long and not just during training sessions fare better, not surprisingly (5).

Some other studies have shown that 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 respond to exercise training if you have type 2 diabetes is limited; in fact, even breaking up prolonged sitting time has measurable metabolic benefits (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!

Read Sheri's bio here.

Read more of Sheri Colberg-Och's columns.

NOTE: The information is not intended to be a replacement or substitute for consultation with a qualified medical professional or for professional medical advice related to diabetes or another medical condition. Please contact your physician or medical professional with any questions and concerns about your medical condition.

Last Modified Date: June 15, 2015

All content on dLife.com is created and reviewed in compliance with our editorial policy.
Sources
  1. Dunstan DW, Kingwell BA, Larsen R, et al.: Breaking Up Prolonged Sitting Reduces Postprandial Glucose and Insulin Responses. Diabetes Care 2012;35:976-983
  2. Dunstan DW, Kingwell BA, Larsen R, et al.: Breaking Up Prolonged Sitting Reduces Postprandial Glucose and Insulin Responses. Diabetes Care 2012;35:976-983
  3. Braun B, Eze P, Stephens BR, et al.: Impact of metformin on peak aerobic capacity. Appl Physiol Nutr Metab 2008;33:61-7
  4. 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
  5. 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
  6. 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
  7. 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
  8. 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

More on this Topic

No items are associated with this tag

Sign up for FREE dLife Newsletters

dLife Membership is FREE! Get exclusive access, free recipes, newsletters, savings, and much more! FPO

Congratulations!
You are subscribed!
Congratulations!
You are subscribed!
Congratulations!
You are subscribed!
2678 Views 0 comments
by Brenda Bell
As I mentioned in an earlier post, one of the benefits that made it cost-effective for me to go with the real healthcare (HSA) plan rather than the phony (HRA) plan is that my company is now covering "preventative" medicines at $0 copay. The formulary for these, as stated by CVS/Caremark (my pharmacy benefits provider), covers all test strips, lancets, and control solutions. I dutifully get my doctor to write up prescriptions for all of my testing needs, submit...
  • Watch dLifeTV online now!

    Click here for more info