Sheri Colberg, Ph.D., FACSM shares more of her new best seller, The 7 Step Diabetes Fitness Plan. This week read: Can you really prevent diabetes just by walking?
Can You Really Prevent Diabetes just by Walking?
By Sheri Colberg, Ph.D., FACSM
Can you really prevent diabetes just by walking?
Type 2 diabetes may actually be preventable with regular physical activity—even just walking. During the past decade, many studies thatassessed people’s exercise habits have concluded that regular physical activity is associated with a lower risk for the development of type 2 diabetes. However, much of this research involved observational studies of large numbers of people using activity questionnaires or brief physical exams to assess their health status, lifestyle habits, and risk, and they relied heavily on often unreliable, self-reported exercise habits. Despite the fact that people tend to exaggerate their exercise habits, self-reported “active” individuals were still generally leaner than their sedentary counterparts, with lower levels of abdominal fat, better BG levels and insulin action, and a lower risk of developing diabetes.
More recently, landmark clinical trials have directly assessed the impact of regular physical activity on the prevention of type 2 diabetes. The Diabetes Prevention Program (DPP) studied 3,234 overweight American adults with impaired glucose tolerance (IGT, diagnosed with an oral glucose tolerance test) at high risk for diabetes, almost half of whom were from high-risk ethnicities (African Americans or Hispanics). Participants in the “lifestyle arm” of the study were asked to follow a low-fat diet and increase their exercise to include 150 minutes (2.5 hours) per week of a moderately intense activity (such as brisk walking) spread out over at least three days and engaged in for a minimum of 10 minutes at a time. The news from this trial was so good that the study was actually wrapped up early. After just three years, people who had changed their lifestyles for the better had reduced their average risk of developing diabetes by a colossal 58 percent—despite their high-risk status. Moreover, this reduced risk was not dependent on ethnicity, age, or sex; in fact, the effect was even greater among older individuals. Moreover, a similar lifestyle study conducted in Finland studying high-risk individuals also resulted in exactly a 58 percent decrease in diabetes risk.
While the DPP study did not test the contribution of physical activity without simultaneous changes in diet and body weight, the active participants lost an average of only 7 percent of their body weight, equivalent to just 14 pounds in a 200-pound person or 21 pounds in a 300-pound person. Subjects in the Finnish study also lost body weight, ate less saturated fat and more fiber, and added 30 minutes of daily walking and occasional resistance training to their regimens. The study proved, among other things, the power of walking: subjects who walked 2.5 hours or more a week had a 63 to 69 percent lower risk of developing diabetes. It also found, however, that a person’s genetic makeup can exert some influence over how effective lifestyle changes are in the prevention of diabetes. For some, total physical activity and a concomitant 5 to 7 percent weight loss had the greatest effect, while for others, the dietary changes appeared to result in a greater benefit.
Even if the protective effect of exercise on your risk for diabetes does vary somewhat depending on your genetic background, it’s still a crucial addition to your lifestyle if you already have diabetes—for all of the physical health reasons discussed, and for some mental health ones that we will cover later (in fitness step 5). It has now been proven that exercise alone can largely control or essentially reverse type 2 diabetes, and any exercise can help your insulin work better, regardless of what type you have. So why aren’t people convinced of the importance of exercise? As with most things, maybe it’s just that people need to be repeatedly hit over the head with a new idea before it finally sinks in.
In two weeks, I will share Part 5 of Step 1 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: When you start exercising more, your weight may not go down very quickly, and it may even go up for a while—but such changes are far from meaning that you aren’t making any headway. Muscle mass is more dense than body fat, so muscle weighs more.
Learn about the new Steps-To-Health Program. A program like no other. It will motivate your patients to increasing their physical activity while they are having fun. http://www.steps-to-health.org/