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Experts Weigh In on Exercise with Diabetes

At the ADCES 2021 conference three diabetes care and education specialists gave their recommendations for how to craft an individual exercise routine and how to avoid common pitfalls.

Everyone knows that exercise is an essential part of a healthy lifestyle. For people with diabetes, staying active and developing a sustainable exercise routine can help maintain fitness and health, reduce insulin resistance for those with type 2 diabetes, and can even slow the progression of the disease over time.

At the ADCES 2021 conference earlier this month, three experts on physical therapy, nutrition, and the physiology of diabetes led sessions about how those with diabetes can establish routine exercise habits, sharing tips and insights about being and staying active. For instance, did you know that, on average, people with diabetes are less likely to exercise than people with either arthritis or obesity? These sessions provided evidence-based recommendations on types of exercise, how exercise can control glucose levels to avoid hypoglycemia, and how to create a safe exercise plan for your needs. 

Exercise as Medicine

In his session, “Exercise as Medicine for People With Diabetes: What, When and Why,” Dr. Christos Katsanos, associate professor at Arizona State University and expert in the physiology of obesity and diabetes, explained how exercise can improve glucose control, what types of exercise are important, and when and for how long people with diabetes should exercise.

Exercise is crucial for people with type 2 diabetes, Dr. Katsanos said, explaining that glucose is the source of energy for many different types of cells in your body, including your muscles. In the absence of diabetes, the action of insulin enables muscles to take up glucose from your blood. This transport of glucose into the muscle cells occurs through the glucose transport receptor, GLUT-4. In type 2 diabetes, the process of glucose uptake through the GLUT-4 receptor is impaired, associated with insulin resistance. When you have type 2 diabetes and you exercise, he said, GLUT-4 receptor function is improved, reducing insulin resistance.

Exercise has many direct and indirect benefits for people with type 2 diabetes, such as reducing insulin resistance, lowering body weight, increasing muscle mass, and improving overall fitness. Dr. Katsanos recommended a combination of the following when creating a personalized exercise regimen: 

  • Aerobic exercise, such as walking, swimming, and cycling, which involves rhythmic muscular activities. 

  • Resistance exercise, which involves activities with resistance bands, free weights, and bodyweight.

In terms of when and for how long to exercise, Dr. Katsanos recommended:

  • Exercising after a meal can be critical. The glucose profiles of those who are sedentary versus active after a meal are significantly different. Dr. Katsanos presented findings from a study in Frontiers in Endocrinology, demonstrating that those who exercise after a meal experience a much higher degree of glucose control and stability than those who remain at rest.

  • Moderate to vigorous aerobic exercise every day. Get at least 30 minutes of this type of movement each day, or at least every 48 hours, not missing consecutive days.

  • Resistance exercise at least 3 non-consecutive days per week. This should include 8-10 different exercises, 1-3 sets each, and anywhere from 6-15 repetitions per exercise. 

  • High-intensity interval training. This involves doing vigorous aerobic exercise for a short period of time (just a few minutes), resting, and then repeating. 

  • Start small! Take minor steps that integrate exercise into your daily routine such as taking the stairs or parking further away when you run errands.

Exercise comes in many varieties and it is important to find activities that are enjoyable and that motivate you. Talk with your healthcare provider before designing a personalized exercise plan to ensure that you stay safe and healthy. 

Overcoming Barriers

In her session, “Create Exercise Programs for People with Diabetes,” Karen Kemmis, a physical therapist and certified diabetes educator at SUNY Upstate Medical University in Syracuse, NY, discussed exercise challenges and barriers for people with diabetes, including balance and movement, and how to develop individualized exercise regimens.

Kemmis said everyone should develop an exercise program for their particular needs in collaboration with a healthcare provider or physical therapist. Common exercise limitations for people with diabetes include range of motion, pain, strength, and balance, she said. People with diabetes, especially those with excess weight, have an increased risk of developing arthritis with stiff joints in the shoulders, hips, and hands. Arthritis can also occur in the hips, knees, ankles, and feet, causing pain and leading to inactivity. 

Kemmis shared a study assessing the impact of diabetes, obesity, arthritis, or a combination, on someone’s propensity for exercise. Results revealed that diabetes had the greatest effect on limiting exercise. For individuals without any of these conditions, about 10% did not engage in physical activity. That number rose to 13.5% for those with obesity only, 17.3% for people with arthritis only, and 21% for people with diabetes. Inactivity levels for people with multiple conditions rose even higher, to nearly 30% for individuals with both arthritis and diabetes. Diabetes can also hinder balance as a result of complications of visual impairment and neuropathy, Kemmis said. 

Kemmis also recommended creating a personalized exercise regimen that suits you in consultation with your healthcare provider. Following suggestions by the American Physical Therapy Association, this includes having the provider take a medical history and test your balance and mobility. Using this information, you and your provider can create a personalized exercise regimen that suits you.

Her recommendations echoed those of Dr. Katsanos’. Recognizing that recommendations for exercise will vary for each person, Kemmis recommended that, in general, exercise guidelines for adults with diabetes should include aerobic exercise 3-7 days per week, resistance and weight training 2-3 days per week. She advised exercising for at least 150 minutes per week.

Some types of exercises that can be especially helpful for people with diabetes include yoga or tai chi, community exercise classes, strength training, and balance, she said. Children with diabetes should get at least one hour of moderate to vigorous physical activity per day with extra focus on muscle and bone strengthening exercises.

Physical Activity and Type 1 Diabetes

Stanford University’s Dr. Dessi Zaharieva, an expert on maintaining glycemic control during and after exercise in adults with type 1 diabetes, led “Reduce Glycemic Fluctuations and Promote Physical Activity in Type 1 Diabetes.” He discussed strategies and challenges for people with type 1 diabetes, focusing on ways to avoid hypoglycemia, which can be a danger during and following exercise. 

Dr. Zaharieva said that consensus guidelines on healthy glucose levels at which to begin exercise change depending on type of exercise (aerobic or anaerobic), duration of exercise, and recent bolus (short acting) insulin dose. Additionally, she cautioned, recommendations are typically individualized to suit the needs of different people. 

Factors that should be considered by those with type 1 diabetes when exercising include:

  • Insulin action and circulation: High circulating insulin levels in the blood can significantly affect blood sugar during exercise. With insulin on board from a prior bolus, the risk of hypoglycemia is especially high.

  • Individual variability: People respond differently to different foods, insulin doses, and medications, requiring a personal approach to exercise.

  • Pre-exercise blood glucose levels: Starting exercise within a healthy blood glucose range is important to avoid hypoglycemia.

  • Education of healthcare providers: Healthcare providers should know the latest recommendations for exercise.

  • Motivation: Patient adherence to exercise recommendations varies and often needs support.

Dr. Zaharieva recommended talking with your healthcare provider or physical therapist to establish exercise goals, such as weight loss or increased activity, intensity, duration, and type of exercise. Planning with an endocrinologist or diabetes care expert for bolus dosing adjustments and having a plan of action in the event of hypoglycemia are critical to prevent hypoglycemia during exercise. 

The use of a continuous glucose monitoring (CGM) system for glucose management should also be considered, Dr. Zaharieva said. Knowing your glucose levels during exercise, watching the trends, looking at the arrows, and having alerts can help maintain glycemic control. CGM devices can provide information on the rate of change to tell you when your glucose levels are increasing or decreasing too quickly. This information can guide decision-making on nutrition and bolus adjustments before, during and after exercise, helping to avoid hypoglycemia.

Dr. Zaharieva also presented data that showed that Time in Range (TIR), which is the percent of each day spent within a healthy glucose range, was higher on days with exercise versus days without exercise. On days with exercise, TIR was higher (62% versus 56% on sedentary days) and average blood glucose levels were down, she said, but time in hypoglycemic ranges was also slightly higher, with percentage of time spent below 70 mg/dL at 9.3% versus 7.1% when sedentary. 

Dr. Zaharieva gave advice on sugar consumption before exercising, bolus adjustments, and strategies to avoid a hypoglycemic episode. Some of these recommendations included:

  • Eating a small snack with 10-15g of carbohydrate before prolonged cardio exercises, such as walking or cycling, with higher food intake for endurance activity.

  • Using CGM is very helpful in identifying glucose trends and alerting you to sudden changes in glucose levels before, during and after exercise. During exercise, there can be a discrepancy between fingerstick glucose and sensor readings – due to the sensor glucose lagging behind the blood glucose. If you have symptoms of hypoglycemia but your sensor reading does not confirm this, you might want to check your blood glucose with a fingerstick. 

  • Reducing insulin administration. For users of open-loop pumps, basal insulin rates should be reduced by 50-80% roughly 90 minutes before exercise. For those using a closed-loop system, setting an exercise or activity target 1-2 hours before activity should be considered. For those on multiple daily injections, recommendations indicate a 10-20% basal insulin reduction on active days. In addition, you might want to consider a reduction in bolus doses within 1-3 hours of exercise. Talk with your endocrinologist or diabetes care expert for more personalized recommendations.

While exercise is typically associated with an increased risk of hypoglycemia, it is still important to consider the risk of hyperglycemia, especially when doing high intensity resistance exercises. Dr. Zaharieva recommended checking your ketone levels prior to exercise and considering a 50% bolus correction.

While type 1 diabetes presents many challenges to exercising safely, Dr. Zaharieva recommended taking small steps toward your goals. These steps can include choosing enjoyable exercises, taking the stairs instead of the elevator, parking farther away from the front door, taking zoom/phone calls while walking, or sitting on an exercise ball as opposed to a chair, which strengthens your balance and core. 

In addition, diaTribe has several resources with information about exercise, diet, nutrition, and managing your glucose levels, which can be found on our exercise page here.