This question is often one of the first I get asked when working with a person with diabetes (PWD). Let’s cut to the chase. What is going to give me the greatest return for my effort? Some people we work with like to exercise and want to know what should be done for the greatest benefit. Others don’t enjoy exercise and want to know what they can do to accomplish the most with the least amount of time and effort.
There are two main types of exercise that have been shown to be beneficial for a PWD: aerobic/cardiovascular endurance exercise and resistance/strength training. There are other categories of exercise, including flexibility/stretching and balance, which might help an individual but have not been shown to improve some key parameters of diabetes management (i.e., lowering blood glucose (BG), burning calories, improving lipids and blood pressure).
Aerobic/cardiovascular endurance exercise is defined by the CDC as “activity in which the body’s large muscles move in a rhythmic manner for a sustained period of time. Aerobic activity…improves cardiorespiratory fitness.” Common examples of aerobic exercise include walking, biking, running, swimming, water aerobics, dancing, sitting aerobics, and hiking to name a few. These exercises are not all equal when it comes to burning calories and lowering BG. In general, the more muscles used, the better the exercise. For example, walking, which uses all of the body’s major muscle groups, will burn more calories than an equal effort of bicycling where the upper body is less active or swimming where the lower body is less active. The harder any exercise is performed, the greater benefit. Brisk walking is more efficient than casual walking. While high intensity exercise may provide greater rewards, it may also increase the risk of injury or lead to a medical problem if a person is not healthy enough (refer to my last blog on intensity). But, the bottom line is the best exercise may be the one that an individual can and will do. Though brisk walking may be a great aerobic exercise, a person may prefer biking or can only do water aerobics due to painful conditions, making the best option the one that will be carried out routinely. If lowering BG or burning calories isn’t a priority, a person can choose the exercise they most enjoy.
Resistance/strength training was not often included in the exercise prescription for a PWD until the early 2000s when a couple of major studies were published that showed strong evidence supporting resistance training for most people with diabetes. The CDC defines “muscle strengthening activity (also called strength or resistance training)” as a “physical activity, including exercise that increases skeletal muscle strength, power, endurance, and mass.” Strengthening exercises have been shown to improve insulin action, BG control, fat metabolism and storage in muscles and muscle mass. Strength training can be especially important for aging individuals to improve the ability to do activities of daily living and maintain independence. Resistance training can be performed by using weight machines, free weights, elastic exercise bands or body weight (such as with pushups and wall slides). If someone has not performed resistance exercise, it may be helpful to work with an exercise professional to learn proper form and technique to avoid injury.
In summary, aerobic exercise and resistance training are the two main types of exercise that should be done by most people (including those with diabetes). In my next blog, I will review frequency and time of exercise to complete this series on the specifics of prescribing exercise for a PWD.