Exercise – and Reducing Sedentary Activities
Protects Women Against Type 2 Diabetes
Excerpt from Women’s Health and Fitness Guide by Michele Kettles, M.D., M.S.P.H., Colette Cole, M.S., and Brenda Wright, Ph.D. (Human Kinetics, 2006)
Type 2 diabetes is one of the top 10 leading causes of death in the United States for women of all races. There is clear data that regular physical activity reduces the risk of type 2 diabetes. Ttpe 2 diabetes has many complications such as cardiovascular disease, damage to eyes and loss of vision (retinopathy), damage to kidneys and kidney failure (nephropathy), nerve dysfunction (neuropathy), and infections (especially in the feet, leading to amputation).
Weight gain and increased BMI are associated with increased risk of developing type 2 diabetes. There is an especially sharp increase in risk of diabetes in women, as compared to men, with increasing BMI. Type 2 diabetes doesn’t develop overnight. It is typically the result of years of low fitness, poor eating habits, and weight gain. Even a modest increase in weight as an adult is associated with an increased risk of type 2 diabetes, hypertension, coronary heart disease, and cholelithiasis (gall bladder disease).
How much exercise is necessary to prevent type 2 diabetes? Interesting data come from the Nurses’ Health Study. In this study, 68,497 nurses were surveyed about their sedentary behaviors, such as watching television, in addition to exercise activities, such as walking.
At the start of the study, none of the women had diabetes. A clear association between sedentary behaviors and development of diabetes was found. By the end of the study 2.2 percent of the women (1,515 cases) were newly diagnosed with type 2 diabetes. Each increment of two hours per day of TV watching was associated with a 14 percent increase in risk of diabetes. Each increment of two hours per day of sitting at work was associated with a 7 percent increase in risk of diabetes. In contrast, standing or walking around the home for two hours per day was associated with a 12 percent reduction in risk for diabetes. Walking briskly for one hour per day was associated with a 34 percent reduction in risk for type 2 diabetes.
For this group of women, it was estimated that 43 percent of new cases of diabetes could have been prevented by reducing television viewing to less than 10 hours per week and adding 30 minutes per day of brisk walking. It is important to note that sedentary behaviors predicted risk for diabetes independent of exercise level. That is, sedentary behaviors must be reduced and exercise activity increased to reduce risk for type 2 diabetes.
Another study from the Nurses’ Health Study followed 70,102 nurses from 1986 to 1992. This study found that the more frequent and more vigorous the exercise, the lower the risk of developing diabetes.
The Diabetes Prevention Program Research Group published a study in 2002 that showed an intensive program of lifestyle change, including instruction in weight reduction through healthy diet and regular physical activity, reduced the risk of developing type 2 diabetes in male and female patients who were at risk. Clearly the most benefit in reducing risk of type 2 diabetes was seen in the group receiving intensive lifestyle change, which even exceeded the benefit seen in the group treated with medication.
An interesting study out of Finland followed both men and women to determine if physical activity prevented type 2 diabetes. In fact, they found that regular physical activity had a more powerful protective effect for women than for men. The level of physical activity in this study was less important than the overall amount of activity performed. Again, it appears that minimizing sedentary behaviors and increasing leisure time physical activity or moderate activity is beneficial in reducing risk of developing type 2 diabetes.
Risk Factors for Type 2 Diabetes in Women
- Family history (genetics)
- Older age (over 55)
- Obesity
- Sedentary lifestyle
- High-calorie diet
All women should be encouraged to participate in regular exercise to minimize risk of impaired fasting glucose and type 2 diabetes. Walking for 30 to 60 minutes on most days of the week and minimizing sedentary behaviors both favor good blood glucose control.
Exercise and Type 2 Diabetes – Summary of Important Findings
- The more frequent and vigorous the exercise, the lower the risk of developing type 2 diabetes.
- Sedentary behaviors (sitting, watching TV) predicted risk for diabetes independent of exercise level.
- Sedentary behaviors must be reduced and exercise activity increased to reduce risk for type 2 diabetes.
- Regular physical activity has a more powerful protective effect against type 2 diabetes for women than for men.
- In women at risk for type 2 diabetes, regular physical activity as part of intensive lifestyle change had a greater benefit than treatment with glucose-lowering medication.
Source
Excerpted from Women’s Health and Fitness Guide by Michele Kettles, M.D., M.S.P.H., Cooper Clinic physician, and Colette Cole, M.S., Cooper Fitness Center personal trainer.