If you’re physically trained, you will generally have a heightened sensitivity to insulin—but why? Sheri Colberg, Ph.D., FACSM shares her reasons in an excerpt of her new best seller, The 7 Step Diabetes Fitness Plan.
Any Training Makes Your Insulin Work Better
By Sheri Colberg, Ph.D., FACSM
Any training makes your insulin work better
If you’re physically trained, you will generally have a heightened sensitivity to insulin—but why? It appears that the answer varies according to the type of training you do. For instance, in lean but sedentary young adult women (ages eighteen to thirty-five) engaging in six months of thrice weekly either endurance (aerobic) or resistance (weight) training, both forms of training improved their glucose use, but by different mechanisms. Weight training apparently results in enhancements in your muscle mass, allowing for greater overall glucose uptake. While endurance training does not increase your muscle mass as much, it does enhance your muscular uptake of BG without changes in body weight or abdominal fat.
What if you’re older or overweight? Training will still work for you. Sedentary, insulin-resistant, middle-aged adults engaging in 30 minutes of moderate walking three to seven days per week for six months succeeded in reversing their prediabetic state—without changing their diets or losing any body weight. In older adults (average of 72 years), all it took was low- to moderate-intensity “walking” on mini-trampolines for 20 to 40 minutes four days per week over a four-month period to enhance their glucose uptake without any additional insulin release or loss of abdominal fat.
If you’re young but obese, you’re still in luck. Studies have shown that, regardless of your age, exercise training can improve your insulin action within just one week of training without weight loss or a true training adaptation in muscle.
Add in some weights to really power up your insulin
In addition to walking, you might want to do some weight training as well to further improve your sensitivity to insulin and better control your BG levels. In people with type 2 diabetes, four to six weeks of moderateintensity (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 (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.
Why “diet” truly is a four-letter word
Not everyone likes to exercise. I know that just telling you that you need to do it is not necessarily going to work. Maybe you’re the kind of person who’d rather go on a diet than have to lift anything heavier than your fork. Let me put a question to you then: since millions of Americans are currently dieting and countless others have already been on one or more diets, why isn’t everyone thin?
How many times have you yourself lost 10, 20, or even 30 or more pounds, only to gain it all back over time? The problem isn’t that you can’t lose weight on a diet—usually you can, as long as you eat fewer calories than your body needs. Even with diabetes, you can lose weight on the famed Atkins “low-carb” diet, mostly because cutting all of the carbohydrates out of your diet causes you to consume significantly fewer calories. The real problem is not losing weight while on the diet; it’s keeping the weight off. Even among successful dieters, an estimated 95 percent regain the same amount (or more) within six months to a year.
Since you may find yourself, post-diet, eating the same kinds of foods you ate pre-diet, the typical rebound response is an excessive intake of calories—particularly in the form of extra fat. Thus you lose the battle against returning to your previous, higher “set” body weight. While this set point can change gradually over your lifetime, it remains the same over the relatively short time-frame of a diet. Therefore, if you don’t adopt permanent lifestyle changes that allow you to gradually reset your body weight to a new, lower one, you will be doomed to regain your lost weight. Also, rapid or extreme weight loss invariably results in a loss of body water and muscle—the loss of which adds to the ease of regaining weight once you resume your normal food intake.
If you have to choose between dieting (and likely regaining all the weight in the end) and becoming more fit, choose the latter. When you experience large fluctuations in body weight over time (also known as “yo-yo” dieting because your weight goes up and down, up and down), you’re likely to be less healthy than people who never lost any or lost very little of their excess body fat. Women whose body weight cycles in this manner may actually have a much greater risk of developing heart disease.
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: You can lose body fat while gaining muscle and actually gain weight. Pay more attention to your waist and hip measurements and to how loose your clothes are getting than to your weight on a regular scale.