My work in diabetes and exercise began in 1987. At that time, there were over 11 million Americans who had diabetes. It was a time of great optimism in the field of endocrinology. During the late 1980s, research in insulin markers, low carb diets, new insulin delivery systems, new glucose monitoring systems and the wide spread use of the HbA1c test for long term glucose control were all being tested in many centers across the country. In the field of exercise and diabetes, James Barnard and Nathin Pritikin were publishing information on low fat diets and low intensity exercise and its treatment for NIDDM. In fact, in the mid to late 1980s, good research was being published on many aspects of exercise and diabetes. Reviews by Per Bjorntorp in Sweden and Edward Horton at the Joslin Diabetes Center in Boston gave comprehensive overviews as to the mechanisms of how exercise worked in enhancing glucose sensitivity and its importance in the spectrum of diabetes care. Cliff Bogardus and his colleagues also published a landmark report on the effects of both diet and exercise on metabolism in NIDDM patients.
The research in the 1980s was cumulated in reviews and books in the 1990s. Barb Campaigne and Dick Lampman published a good review on exercise and diabetes in 1994. This book discussed the application of exercise with patients who were diagnosed with type 1 and type 2 diabetes. The American Diabetes Association published an extensive review on exercise and diabetes in 1995. This book highlights the mechanisms involved in exercise to glucose receptors, changes in general physiology related to chronic exercise, effects of aerobic and strength training programs and nutritional intervention on diabetes control. It is considered one of the better books on the subject. I even jumped into the publishing realm with my Exercise and Diabetes book designed and written for fitness professionals to understand the basics of exercise on physiology and design specific exercise regimes for type 1 and 2 diabetes to improve overall health. Clearly, the decade from the mid 1980s to the mid 1990s was an important time in the understanding of the importance of exercise as part of diabetes management.
Current Diabetes Management
Fast forward 10 years. What has happened to diabetes treatment in the US? To start, there are no national physical activity programs in this country that assist diabetes patients in beginning or maintaining active lifestyles after their diagnosis - even though disuse and sedentary lifestyle is one of the accelerating factors in diabetes complications. The rate of diagnosis of diabetes has increased dramatically in the past 12 years. According to the ADA in 2000, over 16 million people now have diabetes in this country. Almost one in three adults is considered clinically obese. One in four children under the age of 14 is now obese and considered at risk for diabetes diagnosis by the age of 18. Specific groups such as Pima Indians and Hispanics have been targeted as higher risk groups for almost 20 years. However, as of 2000, the diagnosis of diabetes (and subsequent risk factors) has continued to increase in these groups. As a whole, diabetes is considered an epidemic in the US, which was not the case when I started researching exercise and diabetes 15 years ago. With all of the advanced technology and knowledge on diabetes, there is a national crisis. Since one in seven health care dollars goes to fight the complications of long standing diabetes (retinopathy - adult blindness, nephropathy - kidney disease, neuropathy - nervous system disease and angiopathy - heart disease), billions of dollars are going to treat conditions that could be PREVENTED through proper lifestyle management. As important as it may seem, the jobs many doctors are doing could actually be prevented if patients were given a different course of action immediately after their diagnosis of diabetes.
Where Exercise Fits In
We know that exercise may prevent the onset of diabetes from many epidemiological reports. We also know that exercise can lower blood glucose levels, stabilize glycoslyated hemoglobin levels and reduce CHD risk factors. Long term exercise is known to reduce cholesterol, lessen body fat and improve lipid levels. Exercise also reduces systolic blood pressure and reduces the incidence of coronary heart disease. Research by Dr. Dean Ornish suggests that a combination of low fat diet, exercise and meditation can actually reverse this condition. It is not impractical to assume that regular exercise may also reverse beginning stages of foot neuropathy or muscle myopathy in persons with diabetes. Although there is little research in this area, there are some recent case studies that indicate a reduction in complication status with long term exercise.
Why isn’t exercise used more in the fight against diabetes? Perhaps the main reason is the lack of reimbursement dollars afforded to exercise treatment and therapy programs. Therefore, since exercise may not be (in the immediate future) part of the health care and medical system, it is now up to other health professionals to assist in the care of persons with diabetes to improve their quality of life, diabetes condition and educate them on how to begin a self-management program that starts with a regular exercise program.
Dr. George Sheehan states that having patients perform an exercise stress treadmill test does have some merit. However, knowing some medical aspects in diabetes is essential in formulating a program that is sound and safe.
First, have a good idea about basic health measures. Body fat percentage, resting heart rate and blood pressure and lab work (cholesterol, HDL, LDL). The next important measurement is long term blood glucose - called glycosylated hemoglobin (or HbA1c). This measure correlates to long term diabetes health as much as any other measurement.
At the beginning of an exercise program, knowing a health history of your new client is also important. Find out if he or she has had any problems with orthopedic limitations (such as prior surgeries or musculoskeletal injuries) or medications (other than insulins). With this information in hand, the first exercise session may begin.
Phase I and II Exercise
Having the majority of diabetic clients exercise during their first exercise sessions is one of the most effective and safest ways to get them to train. Walking increases caloric expenditure and helps increase glucose utilization. Persons who walk up to 45 minutes a day can decrease blood sugars substantially.
Walking and stretching can make up a great Phase I program. It is easy and can be done each day. Patients will have minimal soreness and learn about the basics of exercise instruction (monitoring heart rate, blood pressure, range of motion exercises, basic muscles that do the exercise, fatigue levels and intensity). Having them also learn to monitor blood glucose levels before and after exercise teaches them another important aspect of exercise and diabetes - that training is "blood glucose dependent."
What does glucose-dependent exercise mean? Simply put, when a diabetic is in good condition, his or her ability to exercise is dependent on the levels of blood sugar in the blood stream. For example, when blood glucose (BGL) is under 100 mg/dl, it may trigger hypoglycemic reactions easier, so exercise is less intense (light walking, stretching, breathing, relaxation sessions). When BGLs are above 250-300 mg/dl, there is more glucose for energy, hypoglycemia is less of a concern and intensity of workouts may be increased (weight training, sports participation, long distance running). This is why knowing blood glucose levels before exercise is so important.
After exercise has become part of the weekly routine, the increased level of instruction begins. Phase II exercise may consist of light strength training, sports conditioning and cross training techniques. This calls for more supervision, as many diabetics are older and have little weight training experience. However, incorporating a classroom exercise, combination of programs and progressive resistance principles enhances overall health, improves fitness status and has a dramatic impact on diabetes control.
Exercise plays an important role in improving health in diabetes. However, there may be thousands of diabetics who exercise in health clubs or at home each year whose health status is never reported because they are not part of a clinical trial or an outcomes project. Therefore, monitoring pre exercise assessments, changes in blood glucose, body weight, blood pressure and fitness status are an important part of the instructor’s job description in working with this population group. Another key element of monitoring and keeping in contact with physicians is having access to a glycosylated hemoglobin reading once or twice per year. Correlating this number to fitness status is very important to show the relationship between the level and duration of exercise and the reduction in HbA1c readings (remember that under 7.0 percent saturation is considered "low risk" by the American Diabetes Association"). It is not uncommon for patients to be in the middle 6.0 to even 5.0 levels of saturation.
The Future of Exercise and Diabetes Management
As more and more health clubs and fitness instructors work with special population groups, diabetics may find part of their health package (and even insurance plan) including the services of exercise professionals. Following these modest guidelines will help professionals perform exercise programs that will entice patients to begin exercise and show them success.
- Health and medical history
- Knowledge of home glucose monitors pre and post exercise
- Start out slow, either walking or on aerobic machines (monitored)
- Move to multi program exercise one-on-one or group
- Follow up fitness and health outcomes regularly
- Share your success with medical community
- REMEMBER - Exercise is blood glucose dependent. Choose intensity wisely.
Instructors should note that there is not one best method of exercise for diabetes. Whether it is walking, aerobic machines, swimming or aquatic exercise, strength training, yoga or Tai Chi, if it helps to lower glucose levels, reduce body fat, improve disease risk factors and keep patients motivated, then it is going to be a good exercise program.
- American Diabetes Association. Exercise and Diabetes. ADA Publications, Alexandria, VA, 1995.
- Barnard, RJ, Lattimore, L, Holly, RG, Cherny, S, Pritikin, N. Response of non-insulin dependent diabetic patients to an intensive program of diet and exercise. Diabetes Care. 5(4):370-74, 1982.
- Bjorntorp, P, Krotkiewski, M. Exercise treatment in diabetes mellitus. Acta Medica Scandinavica. 217(1):3-7, 1985.
- Bogardus, C, Ravussin, E, Robbins, DC, Wolfe, RR, Horton, ES, Simes, EAH. Effects of physical training and diet therapy on carbohydrate metabolism in patients with glucose intolerance in non-insulin dependent diabetes mellitus. Diabetes. 33:311-18, 1984.
- Campaigne, BN, Lampman, DM. Exercise in the Clinical Management of Diabetes. Human Kinetics Publishers, Champaign, IL, 1994.
- Creviston, T., Quinn, L. Exercise and physical activity in the treatment of type 2 diabetes. Nursing Clinics in North America. 36(2): 243-71, 2001.
- Durak, EP. Exercise and Diabetes. Medical Health and Fitness Publications, Santa Barbara, CA Second Ed. 1997.
- Franz, M. Norstrom, K. Diabetes Activity Staying Healthy. DCI Publishing, Minneapolis, MN, 1994.
- Horton, ES. Role and management of exercise in diabetes mellitus. Diabetes Care. 11(2)201-11, 1988.
- Kelley, DE, Goodpaster, BH. Effects of exercise on glucose homeostasis in type 2 diabetes mellitus. Medicine and Science in Sports and Exercise. 33(6Supp): S495-501, 2001.
- Ryder, JW, Chibalin, AV, Zierath, JR. Intracellular mechanism underlying increases in glucose uptake in response to insulin or exercise in skeletal muscle. Acta Physiologica Scandinavica. 171(3):249-57, 2001.
- Schultz, JA, Sprague, MA, Branen, LJ, Lambeth, S. A comparison of views of individuals with type 2 diabetes mellitus and diabetes educators about barriers to diet and exercise. Journal of Community Health. 6(2):99-115, 2000.
- Wing, RR, Epstein, LH, Peternostro-Bayles, M, Kriska, A, Nowalk, MP, Gooding, W. Exercise in a behavioral weight control program for obese patients with type 2 diabetes. Diabetolgia. 31(12):902-09, 1988.