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Like medication, exercise can be dosed based on the characteristics of the individual to increase its benefits and reduce side effects, substantially affecting glucose management.
Diabetes mellitus is a cluster of metabolic disorders characterized by insulin resistance, hyperglycemia, and glucose, lipid, and protein metabolism alterations. It is expected that by 2035, more than 590 million individuals will develop type 2 diabetes mellitus. Epidemiological evidence suggests that sedentary behavior and physical inactivity represents the primary factor associated with an increased risk of type 2 diabetes mellitus and chronic diseases. Lifestyle modification combining diet and physical exercise is the first non-pharmacological therapy for type 2 diabetes mellitus.
Regular physical activity reduces the short-term and long-term incidence of type 2 diabetes mellitus and the amount and dose of insulin and anti-diabetic therapy required in people with diabetes.
Sgro et al. conducted this review to update the connection between physical activity and glucose metabolism in people with type 2 diabetes mellitus, and to highlight the role of physical exercise as a medication for the prevention and treatment of type 2 diabetes mellitus. The most extensive insulin-sensitive tissue is skeletal muscle, which is the leading site of insulin-stimulated glucose uptake and glucose homeostasis regulation. Two separate pathways can activate the molecular mechanisms responsible for glucose metabolism in muscle. One is stimulated by insulin, insulin mimicking agents, and insulin-like growth factors, and another is activated by exercise and muscle contraction.
Physical exercise increases the insulin sensitivity of muscles and acts synergistically with insulin to increase glucose utilization in skeletal muscle. Muscle glucose uptake is stimulated by both resistance and endurance exercise. During exercise, skeletal muscle metabolism relies on muscle glycogen stores and circulating plasma glucose, activating intracellular changes leading to the enhancement of glucose uptake through insulin-dependent and independent mechanisms. It’s been demonstrated that a single session of exercise can enhance glucose uptake, and this can persist for several hours after exercise and until the next day.
The positive effects of physical exercise on glucose tolerance and insulin sensitivity last up to 72 hours; performing physical exercise regularly is critical for therapeutic success. Other positive effects include reducing modifiable cardiovascular risk factors and increasing cardiorespiratory fitness. In addition, physical exercise may improve autonomic and endothelial functions to prevent the onset of peripheral neuropathy. Finally, physical exercise may improve patients’ quality of life and physical capacity in patients with kidney disease.
People with type 2 diabetes mellitus should undertake at least 150 min/week of moderate to vigorous aerobic exercise spread out over three days during the week, with no more than two consecutive days between bouts of aerobic activity. A shorter duration of 75 min/week of vigorous-intensity or interval training may be sufficient for more physically fit and younger patients. Supervised physical exercise has been shown to produce more significant improvements in physical fitness than non-supervised physical exercise intervention.
Physical exercise may modulate the therapeutic effects of non-insulin glucose-lowering therapies. For example, exercise improves metformin’s 72-hour glucose control by reducing the frequency of hyperglycemic peaks. And resistance exercise is more effective than aerobic exercise in patients with type 2 diabetes mellitus taking metformin.
A low-cost and safe type of physical exercise that patients with type 2 diabetes mellitus widely accept is walking. Walking decreases HbA1c, body mass index, and diastolic blood pressure in type 2 diabetes mellitus. If a lack of time is a barrier, high-intensity and short-duration exercise protocols may be considered. Yoga has also been shown to induce a reduction in BMI, blood glucose levels, HbA1c, and lipid levels.
Sgro et al. concluded that exercise plays a pivotal role in glucose management in people with diabetes. Skeletal muscle has a central role in glucose uptake mediated by insulin or stimulated by its contraction. Parameters surrounding physical exercises such as frequency, intensity, time, modality, and timing can be adapted to the characteristics of the individual to induce specific acute and chronic responses. With this in mind, exercise could be dosed like a medication with virtually no side effects.
Practice Pearls:
- Glycemic control is a central objective in preventing and treating type 2 diabetes mellitus, and physical exercise might substantially affect the processes that determine it.
- Exercise can be dosed based on the characteristics of the individual to increase its benefits and reduce side effects.
- When properly dosed and administered, exercise has virtually no side effects.
Sgrò, Paolo, et al. “Exercise as a drug for glucose management and prevention in type 2 diabetes mellitus.” Current opinion in pharmacology vol. 59 (2021):95 – 102. doi.10.1016/j.coph.2021.05.006
Azeezat Rasaki, PharmD Candidate, Florida A&M University