Helping Your Patients Become Active

Exercise and physical activity are major contributors to the prevention and management of diabetes. Dating back as far as 1000 AD, Greek physicians prescribed exercise as a way to improve health. Dr. Elliot P. Joslin encouraged his patients to become more physically active; one method was to get a dog from a local shelter and walk it a few times a day.¹  In the present era of medicine, exercise is a cornerstone of diabetes care. It is prescribed to prevent diabetes, improve diabetes control, and promote weight loss. People with type 2 and some people with type 1 diabetes are often sedentary and in most cases are overweight or obese. These struggles usually have a negative impact on diabetes control. People with diabetes benefit greatly from consistent physical activity because activity helps in managing glucose levels, losing weight, preventing and controlling comorbidities and complications, and improving quality of life.² 

Thus, health care providers should and often do encourage their patients to become physically active. However, clinicians' lack of knowledge with regard to exercise often presents a challenge. Exercise advice must include proper guidance about the appropriate type, duration, and frequency of exercise and about blood glucose management with exercise. This article discusses the basic physiology and glucose metabolism with exercise, barriers to becoming physically active and solutions to those barriers, options for exercise with the presence of diabetes complications and orthopedic issues, and guidance for blood glucose management with exercise.

Glucose is the energy source for the muscles. Type 2 diabetes, with its associated insulin resistance, obesity, hyperinsulinemia, and hypertension,interferes with the glucose supply to the muscles. In type 1 diabetes, lack of insulin production by the β-cells in the pancreas is associated with hyperglycemia, polyuria, polydipsia, polyphagia, blurred vision, and weight loss. An inadequate supply of glucose because of either type 1 or type 2 diabetes results in muscles having difficulty performing movements.³ 

Metabolic response to exercise can be influenced by several factors, such as general health, age, nutritional status, exercise capacity, duration and frequency of exercise, metabolic control, and response to insulin or diabetes medications. Exercise has an immediate effect on the body, including cardiovascular, metabolic, and hormonal changes. At the first stage of exercise, oxygen demand increases as a result of an increase in cardiac output, accompanied by an increase in respiration and blood flow to the muscles. Initially, muscle glycogen stores are utilized as a source of energy until, after several minutes, the liver releases stored glycogen into the bloodstream. After ∼ 20–30 minutes of exercise, muscles begin to use stored fat (free fatty acids) as a source of energy. In addition, hormonal changes also occur in response to exercise. Insulin secretion is reduced, and counterregulatory hormone levels (epinephrine, norepinephrine, cortisol,growth hormone, glucagon) increase, signaling the liver to produce glucose.⁴ 

This relationship between hormones and blood glucose during exercise is important to maintain a healthy blood glucose level. For example, at the end of an exercise session in which a person exercises at a low to moderate intensity, blood glucose decreases and continues decreasing. With vigorous exercise, such as resistance training or intense aerobic training, metabolic demand increases. This leads to an increase in hepatic glucose production and results in hyperglycemia. In people with type 1 diabetes, the pancreas is unable to regulate insulin based on blood glucose levels. Thus, the risk for hypoglycemia is increased, particularly for people who inject a high dose of insulin around exercise time. However, people who do not have enough insulin circulating in their bloodstream are at risk for hyperglycemia. In addition,hyperglycemia can also result from abnormal glucose utilization. When the body cells do not have an adequate supply of glucose, the body begins to break down fats as a source of energy. Ketones are formed as an intermediate step in the breakdown of fats. People with type 1 diabetes must be particularly careful to avoid exercising and creating increased need for energy by the muscles when glucose levels are very high because this may lead to ketoacidosis.⁴ 

After an exercise session, glucose from the bloodstream continues moving to the active muscles for at least 24 hours to replenish muscle and liver glycogen stores. Therefore, there can be a delayed hypoglycemic effect even hours after an exercise session. Further, nocturnal hypoglycemia can occur if a person exercises in the afternoon or evening.⁵ 

Exercise also has important chronic effects. As patients increase the duration and frequency of exercise, more of the protein carrier GLUT 4, which helps increase glucose uptake by the muscles, becomes available to transport glucose to active muscles. Consequently, insulin sensitivity increases,glycemic control improves, weight loss can occur, and complications can be prevented. Over time, exercise can also lead to improvements in cardiovascular function, mental health, and quality of daily living.^6,7 

However, many people with diabetes face barriers to becoming active, even when they understand all the benefits of exercise. Such barriers often include fatigue, depression, fear of hyperglycemia or hypoglycemia, diabetes-related complications, and disliking exercise. Some people may find that although they have taken the first step to becoming active, staying active is difficult. Some people with diabetes report that changing eating habits, checking blood glucose, or taking medications is easier than finding the motivation to be physically active.

Some people with diabetes may report that they “hate exercise”or “are allergic to exercise.” So how do patients get started exercising and stay active? With the help of their health care team, they must recognize their personal barriers and find appropriate solutions. For example,research shows that, among a general population, higher depression scores are associated with a greater number of risk factors, including sedentariness.⁸ Depression, stress, and anxiety are all common among people with diabetes.³  With exercise, many hormonal changes in the brain occur that result in improvement of mood and reduction of depression, stress, and anxiety.⁹ Specifically, evidence supports the notion that exercise increases pleasant-feeling states in the short term and that, in the long term, exercise can be just as beneficial for depressive symptoms as medication.^10,11 Thus, if one can overcome depression-related barriers to exercise, depressive symptoms will actually improve, and depression may no longer be a barrier to continued exercise.

One tip for patients who report diminished motivation to exercise is to find fun and easy activities that require minimal preparation, such as walking outside or on a treadmill or cycling on a stationary recumbent bike while watching TV or listening to music. Any physical activity that a person finds enjoyable works at the beginning; it does not necessarily need to be a structured exercise, although structure can be added later if necessary.

In addition, several more logistical barriers can be addressed. If time is a barrier, suggest scheduling 10-minute time slots for exercise. Exercise sessions can be split into two or three shorter sessions a day, and the same benefits can still be achieved.¹² Splitting exercise sessions could also work well for those who have no energy and feel fatigue. Patients may find that exercising at times when energy levels are higher is easier. Over time, exercise will increase energy levels,so this barrier can be easily overcome if patients can just get started.

Joining a health club may be an option for some people who need a place to exercise. However, others cannot afford or are uncomfortable working out in the neighborhood gym. Borrowing fitness DVDs and tapes from the public library and exercising at home or investing in a piece of exercise equipment could increase the chance of maintaining an exercise program. Making friends with people who are active or exercising with family members and friends can help patients to stay motivated and feel both supported and supportive. For example, in a 20-week behavioral weight control program in which obese patients with type 2 diabetes participated either alone or with their spouses,women were more successful in losing weight with the added social support from their spouses. However, men were more successful when participating in the program independently.¹³ 

If a patient is worried about not having the proper skills to exercise or about getting injured during exercise, working with a personal trainer or joining an exercise class could be a helpful option.¹⁴  As patients become active, these individualized barriers may persist, and new solutions may be necessary.

Once patients are ready to begin exercising, they should attain clearance to do so from a primary care physician before starting. An ophthalmic examination with dilated pupils should also be performed before starting resistance training, vigorous exercise, or any activity that may increase pressure in the retina or suddenly improve glycemic control.¹⁵ 

Caution should always be used when prescribing exercise for patients with diabetes complications or orthopedic issues. For example, health care professionals often recommend walking to their patients because it is a weight-bearing activity that is relatively easy to perform and does not require a lot of preparation or skills. However, people with diabetes may develop muscle-skeletal problems because of their sedentary lifestyle,obesity, and deconditioning that may limit their ability to walk. Diabetes complications, such as peripheral neuropathy and Charcot foot, and additional medical problems, such as arthritis, peripheral vascular disease, and peripheral arterial disease, may also limit activity. Therefore, walking may no longer be an easy activity and may, in fact, become very challenging.

Appropriate recommendations for safe and easy activities for people who are physically limited are imperative. Participation in non–weight-bearing activities is easier, more comfortable, can be done for a longer period of time, and does not carry the same risks of injury or the worsening of complications or other medical problems. Examples of non–weight-bearing activities that might be good recommendations include the use of a recumbent stationary bike or arm ergometer, water exercise or swimming, and chair exercises using a DVD or tape.⁷ 

Understanding and being able to explain the different types of exercise that are each necessary for optimal health is important. The American College of Sports Medicine (ACSM) and the American Heart Association suggest performing aerobic, resistance, and stretching exercises. Aerobic exercise refers to a continuous activity that elevates heart rate, increases breathing frequency, involves major muscle groups, and improves endurance.⁹ Resistance exercise refers to an activity that is conducted against force,whether external weight or body weight, that targets major muscle groups. Resistance training promotes weight loss by increasing muscle mass, which increases metabolism. It also increases muscle strength, which improves quality of daily living, reduces the risk of injury, and increases muscle mass and muscle tone, which can improve self-image. Finally, resistance training increases bone density, which helps to prevent osteoporosis.¹⁶ Stretching exercise is performed at the end of an exercise session and loosens the muscles after contraction and lessens the risk of muscle-skeletal injury.⁹ 

Recommendations for the frequency and duration for each type of exercise should be clear to achieve the maximum benefits. Every adult should engage in aerobic exercise that elevates breathing and heart rate for at least 30 minutes, five days of the week, to improve endurance. To attain the maximum health benefit, improve diabetes control, and maximize caloric expenditure,individuals should exercise daily at low to moderate intensity for 60 minutes or more. The activity can be accumulated throughout the day with a minimum of 10 minutes or more for each exercise bout. The ACSM suggests that adults should perform resistance training two or more days of the week with at least 48 hours between sessions. This includes 8–10 exercises that target major muscle groups that can be performed in sets of 8–12 repetitions. Stretching exercises should also be performed daily when muscles are warmed up.^2,12 

For people with diabetes, resistance training can be particularly beneficial. Research has shown that resistance training improves hemoglobin A_1c; reduces subcutaneous and intra-abdominal fat tissue; increases fat free mass; reduces LDL cholesterol, triglycerides, and total cholesterol;and reduces waist circumference.^17,18 Resistance training in combination with aerobic exercise is beneficial in reducing risk factor indicators, improving exercise capacity, and reducing weight.^19,20 

Clinicians, therefore, should advise patients with diabetes to engage in a combination of aerobic and resistance training. People who are members of a health club can use the resistance machines in a gym; others can obtain home resistance machines. For people who prefer exercising at home but cannot afford expensive equipment, free weights or stretching (tubing) bands can provide similar benefits.

No matter where patients choose to exercise, proper form of exercises is essential to prevent injury and the exacerbation of diabetes complications. For patients with diabetes, blood glucose should be monitored and managed before, during, and after exercise to prevent hypoglycemia or hyperglycemia. Keeping records of activity, blood glucose levels, and insulin or diabetes medications doses is an important tool for health care providers and patients to use to prevent or address hypoglycemia or hyperglycemia during exercise and physical activity. This information is also useful when a patient's goal is weight loss.

As patients become more active and lose weight, their insulin and diabetes oral medications may require adjustment. Reduction in medication use could also be a great motivator for patients to stay active and continue improving their diabetes control. Table 1offers strategies for blood glucose management before, during, and after exercise.⁵ 

Exercise and physical activity are known to have acute and chronic benefits for people with diabetes and should always be incorporated to improve glycemic control and promote weight loss. Prescribing an appropriate exercise plan that takes into account patients' diabetes complications and orthopedic issues is imperative. Health care professionals can help patients overcome barriers to exercise by providing them with an understanding of glucose management during exercise and helping them create an exercise routine that is unique to their health status, age, current exercise capacity, glycemic control, and personal goals. Providing these services will help patients get on track to a healthier, happier, more physically active life.TBL2