Improve Blood Glucose Control and Insulin Sensitivity Through Exercise
It is well known that Type 2 diabetes and obesity are at an all-time high in North America. Exercise is vital in the prevention and treatment of these chronic diseases.
Glucose is the main sugar found in our blood and is our primary source of energy. If not taken directly from the blood into the cells to be used as energy, it is stored (known as glycogen when stored) in either the muscle or liver cells for later use.
Insulin is the hormone that allows our body to use glucose from the blood for energy and is affected by both Type 1 and Type 2 diabetes. Type 1 diabetes is an autoimmune disease and occurs when the body’s immune system has attacked the insulin-creating cells of the pancreas. This is often diagnosed early in life and requires insulin to be taken extraneously. Type 2 diabetes is a chronic disease that occurs when your body becomes resistant to the effects of insulin. Eventually, the insulin-creating cells get burnt out and can’t produce enough insulin to bring blood sugars down. Individuals with Type 2 diabetes usually require medication and, potentially, insulin supplementation. Lifestyle is one of the biggest predictors of Type 2 diabetes. It differs from Type 1 because lifestyle changes can also be used to treat this condition and, in some cases, even reverse it.
Acute and Chronic Effects of Exercise on Blood Glucose Control and Insulin Sensitivity
There is an acute response to exercise that is immediately beneficial regarding blood glucose control and insulin sensitivity. A single bout of exercise promotes acute increases in glucose uptake into the skeletal muscle, both during the exercise bout and for some hours post-exercise (depending on the intensity of exercise and the amount of muscle glycogen used) (1). Additionally, whole-body insulin sensitivity is seen immediately after exercise and persists for up to 96 hours (2). While a discrete bout of exercise provides substantial metabolic benefits for diabetics and pre-diabetics, maintenance of glucose control and insulin sensitivity are maximized by physiologic adaptations that only occur with exercise training that is consistent over weeks, months, and years.
So, yes, even one single workout can improve your blood sugars and insulin sensitivity. However, these effects will wear off if exercise is not repeated within a few days. Consistent exercise over long periods of time will lead to positive adaptations in addition to the transient improvements we get from a bout of exercise in these two physiological markers. Refer to Figure 1 below for a tissue-specific look at the effects of exercise on insulin sensitivity in patients with Type 2 diabetes. 
Figure 1. Tissue-specific metabolic effects of exercise in patients with type 2 diabetes (2). What type of exercise is best for improving blood glucose control and insulin sensitivity?Evidence suggests a combination of both aerobic exercise and resistance training to optimize glycemic control and insulin sensitivity, with high-intensity interval training (HIIT) training showing potentially even more benefit than moderate-intensity aerobic training. This applies to apparently healthy individuals as well as those with insulin resistance.If you have any questions about exercising with diabetes or pre-diabetes, or are wanting to know more about how to design an exercise program to help optimize your health, please reach out!
It is well accepted that adults who maintain a physically active lifestyle can reduce their risk of developing impaired glucose tolerance, insulin resistance, and Type 2 diabetes. Health benefits from regular exercise include enhanced insulin signaling, glycemic control, and blood lipid profile, as well as reduced low-grade inflammation, improved vascular function, and weight loss.
Krystyna Woodson
Clinical Exercise Physiologist