Last week Sheri Colberg, Ph.D., FACSM discussed how physical activity improves insulin sensitivity, now in a special excerpt of her new best seller, The 7 Step Diabetes Fitness Plan, she lets us in on other ways to improve sensitivity. This will be a great on to print for your patients.
Factors that Affect the Action of Your Insulin
By Sheri Colberg, Ph.D., FACSM
You now know that physical training enhances your sensitivity to insulin, but not all training is equally effective. In addition to engaging in more aerobic exercise training, you may want to do some weight training as well to further improve your sensitivity to insulin and better control your diabetes. In people with type 2 diabetes, four to six weeks of moderate intensity (40 to 50 percent of maximal) resistance training improved their insulin sensitivity by 48 percent without causing any significant changes in their body fat or muscle mass. Similarly, newly diagnosed type 2 diabetic men who did 16 weeks of “progressive” resistance training (i.e., the resistance lifted was increased over time) just twice a week gained muscle mass, lost body fat (particularly in the abdominal region), and greatly enhanced their insulin action—all despite a 15 percent increase in the amount of calories they consumed. Likewise, if you’re an older, type 2 diabetic woman, the combination of aerobic and resistance training may afford even greater improvements in your insulin action and a more significant decrease in your abdominal fat than aerobic training alone, with increased muscle mass to boot.
Furthermore, it appears that scientists may have jumped to the wrong conclusion when they decided to blame fat cells alone for everything that ails you, including insulin resistance and type 2 diabetes. Granted, the vast majority of insulin-resistant people (with prediabetes or type 2 diabetes) are indeed overweight, but not all people who are overly fat are insulin resistant. Besides, it is fully possible to reverse prediabetes without a significant loss of body fat simply by implementing positive changes in your exercise and dietary habits.
While almost any type of training is a great way to get more “sensitive,” you may not be aware that many other factors can positively impact your insulin’s effectiveness as well. Included below is a “short” list of some of them:
Other Factors That Can Improve Insulin Sensitivity
o Regular aerobic and resistance exercise
o Muscle mass gain
o Loss of body fat—particularly intra-abdominal (visceral) fat, extra fat stored in the liver, and possibly some of the excess fat in muscles
o Improved blood glucose control (and avoidance of highs and lows)
o Reduced levels of circulating free fatty acids (one type of fat in blood)
o Reduction in low-level, systemic inflammation (via suppression of TNF-alpha, a marker of inflammation)—mainly accomplished through physical activity and antioxidants
o More effective action of leptin, a hormone released by fat cells, causing reduced food intake
o Reduction in mental (anxiety, depression) and/or physical (illness, etc.) stressors
o Decrease in circulating levels of cortisol, a hormone released in response to all forms of stress (i.e., physical and mental)
o Increased testosterone levels in men
o Intake of more dietary fiber, less saturated and trans fat, and fewer highly refined foods with a high glycemic effect
o Daily consumption of a healthy breakfast
o Lower caffeine intake
o Adequate sleep (seven to eight hours a night for most adults)
o Effective treatment of sleep apnea
o Use of insulin-sensitizing oral medications (like Avandia or Actos)
The best strategy for optimizing your insulin action, then, is likely a combination of these factors and not just exercise alone. Certainly, you should always include varied types and intensities of exercise into your daily and weekly routine, but additionally eat a healthy breakfast every day, consume more fiber and foods with a lower glycemic effect, moderate your caffeine intake, try to get enough sleep, find ways to more effectively manage your daily stress, and take advantage of insulin-sensitizing medications as part of your diabetes management plan. Not unexpectedly, daily exercise can help you accomplish a lot of these goals, such as managing stress and sleeping better.
In two weeks, I will share more tips and ideas from my latest book, The 7 Step Diabetes Fitness Plan: Living Well and Being Fit with Diabetes, No Matter Your Weight (2006). Information about all of my books, my many articles, my research, and more is available on my web site: www.SheriColberg.com.
Tip for the day: Although being overly fat is not ideal for your health, any potentially negative metabolic effects of excess body fat can be favorably moderated to a large extent by becoming physically fit and remaining regularly active.