by Kristina Sandstedt, M.S., C.D.E., E.S.
Includes photo of Kristina Sandstedt.
How does one define "regular exercise?" We often hear a variety of different time durations, frequencies and intensities, related to appropriate exercise regimens. Whether it is 30-minutes everyday, 20 to 30 minutes three times per week, or one hour four to five days per week at 75 to 80 percent of maximum, we are barraged with numerous formulas that often confuse us rather than help us answer our initial question. It is no wonder 60 to 80 percent of individuals with diabetes do not meet exercise guidelines (McKay et.al., 2002). Part of the problem is the uncertainty of knowing how much, how often and how hard.
Much has been discussed and documented regarding diabetes and cardiovascular disease. According to Dr. Richard Nesto, spokesperson for the American Heart Association and chairman of the department of cardiovascular medicine at Lahey Clinic Medical Center in Burlington, Mass., "By the time a person is diagnosed with type 2 diabetes, they are already at high risk for cardiovascular disease." He continues, "The reality is that heart disease is responsible for the majority of deaths in people with diabetes."
Furthermore, researchers and health care professional have estimated that 80 percent of individuals with diabetes will die of heart related complications--and according to a new survey commissioned by the American Diabetes Association and the American College of Cardiology, 68 percent of people with diabetes are not aware of the correlation. In addition, only 33 percent of people with type 2 DM consider heart disease to be among the "most serious" diabetes related complications. It seems evident that diabetes is a cardiovascular disease and more education regarding the correlation is warranted.
Market research firm RoperASW conducted a survey of 2,008 people that supported this discrepancy--between the perception and reality of the diabetes/heart disease correlation. Interviews were conducted using random direct dial screenings of US households. Results were weighted and projected to match the US diagnosed diabetes patient population of 10.7 million, based on information from the National Center for Health Statistics and the Centers for Disease Control and Prevention (CDC). Although studies have shown that most people with diabetes have other cardiovascular disease risk factors such as high blood pressure and cholesterol, the people surveyed did not share concern for those risk factors. More than half of the people with diabetes who were polled did not feel at risk for a heart condition (52 percent) or stroke (53 percent), and nearly two thirds (60 percent) did not feel at risk for either high blood pressure or cholesterol.
When discussing the implications of these findings, Christopher D. Saudek, MD, president of the American Diabetes Association, suggested, "Education is vital. This research points out that people with diabetes, especially older adults and high risk groups such as African Americans, Hispanics and Native Americans, need to know that good diabetes management is more than just lowering blood glucose. They also need to know how, in addition to managing their weight and increasing physical activity, they can reduce cardiovascular risks such as taking aspirin or prescription medications for lowering high blood pressure and cholesterol, and quitting smoking."
Dr. Harry Pigman (2002) and his research team performed a study evaluating the effects of exercise in management of patients with type 2 diabetes. Their findings revealed that after adjusting for age, race, smoking, BMI, diet and various diabetes medications, patients without regular exercise, defined as walking between 30-60 minutes daily, were nearly three times more likely than patients with regular exercise to have poor diabetes control (HbA greater than 8.0). Furthermore, the researchers have reported a dose-response relationship between the amount of physical activity and the degree of reduction in diabetes risk, while others have not. A general agreement among most researchers is that regular vigorous physical activity affords the greatest health benefits, but even moderate physical activity offers significant benefit. This finding is consistent with the theory that exercise is essential for good blood glucose control. In addition, exercise lowers adipose tissue, which has a positive effect on insulin sensitivity and glucose tolerance. A reduction in free fatty acid (FFA) levels is also observed when adipose tissue decreases. Many studies are currently underway investigating the role of FFA and blood glucose control.
When prescribing exercise to a client with diabetes, it is important to consider the increased risk for cardiovascular disease. Specifically, it is essential to tailor the exercise regimen to meet the exercise goals of an individual with documented coronary artery disease. For such clients, recommending an exercise regimen that would result in a minimum of 1500 calories expended per week is ideal. Such a recommendation is based on numerous lifestyle and medical intervention studies looking at secondary prevention of coronary artery disease. These studies include but are not limited to the Ornish Lifestyle Heart Trial, the Heidelberg study of secondary prevention of CAD, and St. Thomas Atherosclerosis Regression Study. For example, the Heidelberg trial demonstrated that it took 2000-2200 calories per week to cause regression of coronary artery disease and 1500 to stabilize coronary atherosclerosis. The American College of Sports Medicine and American Heart Association support and recommend similar guidelines.
It takes most cardiac patients with low-to-moderate exercise capacity about three to five hours (180-300 minutes) per week to expend 1500 calories or more. This can be achieved in both structured exercise programs and by increasing lifestyle physical activity. Examples of lifestyle physical activity are, parking further away from destination, taking stairs instead of elevator, walking on a lunch break, walking to your mailbox, gardening, and housework.
It is preferred to present exercise duration in terms of minutes because most people feel they have more minutes in their day rather than hours. By providing minutes, clients can decide how they want to accumulate their exercise time, week by week. Specifically, if a client knows they will only have four days to achieve 180 minutes of the exercise, then they should exercise for 45 minutes each session. Likewise, if they have six days, then they should exercise for 30 minutes each session. It is important to note that ideally clients should try to spread the three to five hours over four to seven days. I believe it is very effective to break up the total exercise duration into 10-15 minute segments, two to three times per day, especially with novice exercisers more likely to have low exercise capacities. This ultimately increases compliance, as the client experiences his or her own individual success.
As clients achieve improved physical conditioning, I encourage them to extend one of their exercise segments, therefore eliminating the multiple exercise sessions per day. This puts the client on track to achieving not only good blood glucose control but also decreasing and/or managing cardiovascular risk factors.
Intensity plays an important role in exercise, and I prefer to explain the intensity component using the Rate of Perceived Exertion Scale (Borg). It is important to tell the client to pay attention to their breathing. Most of us breathe through our noses when we are in a resting or low impact state. When we place exertional demands on our body we require more oxygenated flow, and therefore we begin to open our mouths. I explain that complete mouth breathing is a good indicator that you have reached the appropriate intensity. Open-mouth breathing, feeling warm, perhaps perspiring, and broken-up sentences when talking, corresponds to a "13--Somewhat Heavy" on the Perceived Exertion Scale. A client is exercising at the optimal intensity if, when asked to rate how hard the exercise feels, they respond with a "13--or Somewhat Heavy." It is ideal to have the client exercising while the perceived exertion scale is explained. By doing this, the intensity component is better understood--however, this is not always conducive in a classroom setting.
It is very important to recognize when exercise is contraindicated for an
individual with diabetes and/or coronary artery disease. Exercise is contraindicated
if clients have a resting blood pressure of 210mmHg over 110mmHg and/or exacerbated
systolic and/or diastolic blood pressure responses to aerobic exercise (systolic
pressure greater than 260mmHg, diastolic pressure greater than 120mmHg). Other
contraindications are uncontrolled blood glucose causing the presence of ketones
and uncontrolled congested heart failure. Refer to American College of
Sports Medicine Guidelines, sixth edition and/or The American Association
of Cardiovascular and Pulmonary Rehabilitation Guidelines, third edition
for a more extensive list of contraindications to exercise.
If your client does not fall under the contraindications for exercise, it is
extremely important to encourage them to start a structured exercise program
that emphasizes aerobic activity. Too many clients with diabetes are not encouraged
to exercise at their full potential, therefore preventing them from not only
achieving optimal benefit for blood glucose control, but also effective management
of risk factors for coronary artery disease.
Individuals with diabetes who suffer from chronic complications often do not take part in physical activity programs. It is extremely useful for this population to undertake an exercise program to improve or maintain their functional capacity, strength, and flexibility. It is always important to perform a comprehensive assessment to determine the most appropriate exercises, specifically land or water. For exercise recommendations to accommodate specific diabetes complications, refer to the fourth edition of the AADE's Core Curriculum for Diabetes Education.
Kristina Sandstedt, M.S., C.D.E., E.S., received her Masters of Science degree from the University of Montana-Missoula. She is a Certified Diabetes Educator and is also a certified Exercise Specialist through the American College of Sports Medicine. She is the program coordinator for Boone Hospital's ADA certified outpatient diabetes center located in WELLAWARE. Columbia, MO.