Susan Weiner, MS, RDN, CDN, CDCES, FADCES; Michael See, MS, CDCES, ACSM-CEP, NBC-HWC , 2025-04-18 14:44:00
April 18, 2025
5 min read
In this Diabetes in Real Life column, Susan Weiner, MS, RDN, CDN, CDCES, FACES, talks with Michael See, MS, CDCES, ACSM-CEP, NBC-HWC, about tips for exercise for people living with diabetes.
Weiner: Why is exercise the foundation of diabetes prevention and management?
See: Exercise and medical nutrition therapy are the cornerstones of diabetes therapy. Clinical trials and prospective cohort studies have demonstrated that moderate to high levels of physical activity or physical fitness positively correlate with type 2 diabetes prevention, treatment and disease-associated morbidity and mortality.
Exercise is crucial in enhancing glucose disposal and improving insulin action, making it a valuable tool for regulating glucose levels. This direct impact on glucose regulation underscores the importance of exercise in diabetes management and prevention. Additionally, the acute and chronic effects of exercise favorably impact metabolic rate, lipid mobilization, body composition, cardiac and vascular function, the immune system and cognitive function, to name a few.
Weiner: How much exercise should I recommend to people living with diabetes?
See: This is an excellent question. A dose-response association exists between the volume of physical activity and health benefits. I look at exercise along a continuum of benefits from health, fitness and performance. Some exercise is better than none, more exercise is better than some and too much exercise, too fast, can be detrimental. The most significant health benefits occur among individuals who progress from inactive to minimally active.
Individualization based on the individual’s history, interests, resources, goals and desires is key. At a practical level, it is helpful to ask questions about their ability to climb stairs, any changes in their ability to walk a given distance, and if they’ve experienced any changes in perceived exertion or shortness of breath with activity. Use motivational interviewing strategies to assess exercise habits and desires, abilities, reasons and needs for being active.
Weiner: What about the recommended types of exercise?
See: Aerobic exercises such as walking or jogging, biking and dancing are the most efficient for increasing caloric expenditure and reducing cardiovascular risk. Thirty minutes 5 days per week is recommended, but short bouts of activity of 10 minutes or more to interrupt sedentary time are also beneficial.
Resistance training is a potent stimulus of muscle strength and hypertrophy, even in older adults; it’s unsurprising that incorporating resistance training in an exercise program results in more significant benefits than aerobic training alone. Studies have demonstrated that a combination of aerobic and resistance training improves HbA1c levels in people with type 2 diabetes more than either exercise alone. Resistance training twice weekly is recommended, focusing on all major muscle groups using resistance bands, body weight, free weights and/or weight machines. Individuals will often require assistance to get started on a resistance training program.
Additionally, flexibility or mobility exercises should be done 2 to 3 days per week, ideally daily, to maintain muscle and joint function. Balance training 2 to 3 days per week is recommended for individuals at risk for falling.
Weiner: What is the role of physical activity in weight loss and weight maintenance?
See: While exercise and physical activity generally significantly benefit CV and all-cause mortality, morbidity and quality of life, using that alone for weight reduction has minimal impact. Physical activity up to and above 60 minutes a day may be required when relying on exercise alone for weight loss.
Caloric restriction, in conjunction with exercise and physical activity, is the foundation of weight management. A systematic review published in Nutrition Reviews showed that adding primarily aerobic exercise to moderate energy restriction weight loss does not appear to have an additive effect on weight loss, but it can attenuate the loss of fat-free mass in postmenopausal women and men older than 50 years with overweight and obesity.
Given that resistance training is a potent stimulus of muscle hypertrophy, it would not be surprising if the addition of resistance training to a weight management program would preserve fat-free mass and improve function to a greater extent than aerobic training alone. In a meta-analysis published in Nutrients, caloric restriction and resistance training prevented 93% of lean body mass loss induced by caloric restriction.
It is important not to focus on the potential for weight loss as the sole outcome of exercise, but to suggest that exercise may contribute to weight-loss efforts. Exercise and physical activity results in many other health-related benefits. This focus will reduce the likelihood of patients using the lack of weight loss as a reason to discontinue their exercise program.
Weiner: How does exercise help with incretin-based therapies for diabetes?
See: The advent of enteropancreatic hormone-based molecules such as GLP-1 receptor agonists has established a new era in treating excess adiposity, with mean weight loss of 15% to 25% at 1 to 1.5 years and a favorable impact on obesity-related complications approaching that achieved by bariatric surgery.
Ideally, intentional weight loss should come from the loss of fat mass while preserving critical components of lean or fat-free mass, including skeletal muscle mass, bone loss, and maintaining or improving physical function and its accompanying impact on resting energy expenditure.
There are currently limited studies examining the impact of GLP-1 therapy and exercise. In a randomized, head-to-head, placebo-controlled trial that looked at exercise, treatment with liraglutide (Saxenda, Novo Nordisk) and both exercise and liraglutide combined for healthy weight-loss maintenance, the combined strategy reduced body weight and body-fat percentage approximately twice as much as the single-treatment strategies and was associated with additional health benefits, such as improvements in glycated hemoglobin levels, insulin sensitivity, cardiorespiratory fitness, physical functioning and emotional well-being, according to data published in Obesity.
Additionally, individuals at risk for sarcopenic obesity should be evaluated because loss of skeletal muscle mass and strength can adversely affect their functional status.
Gradually incorporating exercise into these patients’ treatment plans may help alleviate weakness and fatigue associated with these therapies.
Weiner: How should I counsel people with diabetes on insulin or secretagogues about blood sugar management?
See: Unplanned exercise or increased physical activity can result in hypoglycemia in an individual treated with secretagogues or insulin therapy. This is a significant deterrent to being active.
Health care professionals should encourage patients to self-monitor blood sugar and/or review continuous glucose monitor data an hour before, during and after exercise to assess trends. If blood sugar is less than 100 mg/dL or lower, take 15 g to 20 g of rapid-acting carbohydrates to raise it. Additional carbohydrates may need to be taken during exercise, depending on the type, intensity, duration, time of day and other factors that impact glycemia during exercise.
To reduce the amount of insulin, consider reducing rapid-acting insulin by 25% to 75% in the 1 to 2 hours before planned exercise. Individuals using insulin pump therapy can program temporary basal reductions leading up to exercise.
Blood sugar management is a process of trial and correction, and various strategies can be implemented to achieve desirable glycemic control (120 mg/dL to 180 mg/dL) during and after exercise.
Weiner: How will different types of exercise affect blood sugar?
See: Numerous factors impact blood sugar during and after exercise. Some important variables are the presence of exogenous insulin or the use of secretagogues, type of diabetes, type of exercise, duration intensity, time of day, training status, composition and amount of previous food and drink consumed, hydration, glycemic control, age and sex.
Low- to moderate-intensity exercise tends to lower or maintain blood sugar depending upon duration. In contrast, during high-intensity exercise, a rise in catecholamines increases glucose production by the liver while limiting glucose disposal into skeletal muscle, resulting in elevated blood sugar.
- For more information:
- Michael See, MS, CDCES, ACSM-CEP, NBC-HWC, is a clinical exercise physiologist and consultant on cardiometabolic health and exercise, diabetes-related technology and health coaching. He can be reached at michaelsee35@gmail.com.
- Susan Weiner, MS, RDN, CDN, CDCES, FADCES, is co-author of The Complete Diabetes Organizer and Diabetes: 365 Tips for Living Well. She is the owner of Susan Weiner Nutrition PLLC and is the Healio | Endocrine Today Diabetes in Real Life column editor. She can be reached at susan@susanweinernutrition.com; X (Twitter): @susangweiner; Instagram: @susanweinernutrition.