Exercise is important for everyone, but it is especially important for diabetics. Being physically active on most days of the week keeps you healthy by lowering your long-term health risks, boosting insulin sensitivity, and improving your mood and overall quality of life. Working out usually produces a drop in blood glucose. However, some people observe that their glucose levels spike during or after specific types of activity.
The researchers wanted to know if high blood glucose blunts the body’s response to exercise and if reducing it can restore the ability to develop aerobic capacity with training. The researchers’ findings imply that a combination of a glucose-lowering drug and exercise may help persons with high blood sugar, or hyperglycemia, increase their exercise capacity.
Exercise has numerous advantages for everyone. Physical activity can help persons with metabolic illnesses such as pre-diabetes, type 1 diabetes, and type 2 diabetes maintain healthy blood sugar levels and avoid diabetes-related nerve damage and heart disease. Persons with diabetes, on the other hand, have poorer aerobic exercise capacity than people without metabolic disease, which means their systems don’t burn oxygen as efficiently and may be resistive to boosting exercise capacity through training.
In a new study, scientists in the Research Division at Joslin Diabetes Center sought to determine whether high blood glucose blunts the body’s response to exercise and whether lowering it can restore the ability to improve aerobic capacity with training. The team’s findings, published in the journal Diabetes, suggest that a combination of a glucose-lowering medication and exercise may work to improve exercise capacity in people with high blood sugar, or hyperglycemia.
We discovered that having high blood sugar for extended periods of time affects the way muscles adapt to exercise at the molecular level. The good news is that we discovered that taking the medicine canagliflozin to reduce blood glucose levels in diabetic mice can prevent the deficits that diminish benefits in exercise capacity that occur with high blood glucose.
Sarah J. Lessard
“As the prevalence of metabolic disease rises, low exercise capacity associated with high blood glucose has the potential to impact a large and growing proportion of the population,” said Sarah J. Lessard, PhD, an assistant investigator in the section of Clinical, Behavioral, and Outcomes Research at the Joslin Diabetes Center and a Harvard Medical School instructor of medicine. “Understanding why certain people’s bodies resist increasing their exercise capacity even with training can assist us in developing measures to promote health and longevity in this population.”
Lessard and colleagues first investigated a medication called canagliflozin, which can lower blood glucose levels in a mouse model, in this two-part study. During the six-week trial, mice with induced hyperglycemia were followed as they ran on exercise wheels willingly. When the scientists analyzed the animals’ responses to exercise training, they discovered that those who had been given canagliflozin performed far better than those who had not.
The researchers were also able to identify specific chemicals in skeletal muscles responsible for reduced exercise capacity in the context of high blood glucose by analyzing the animals’ muscle tissue.
The researchers were then able to establish that the chemicals found in pre-clinical experiments may also be significant in humans by using small samples of muscle collected from human study participants before and after exercise sessions.
“We discovered that having high blood sugar for extended periods of time affects the way muscles adapt to exercise at the molecular level,” Lessard explained. “The good news is that we discovered that taking the medicine canagliflozin to reduce blood glucose levels in diabetic mice can prevent the deficits that diminish benefits in exercise capacity that occur with high blood glucose.”
Lessard and colleagues intend to explore if other glucose-lowering treatments, such as dietary measures, can be as successful as medication therapy in increasing exercise responsiveness as a following step. They are also researching the molecular signaling events in muscle that lead to inadequate remodeling and exercise response. “We can create targeted medicines to restore the exercise response if we can obtain a better knowledge of how elevated blood sugar contributes to these alterations in muscle,” Lessard added.
Walking, for example, causes your heart to beat faster and your breathing to become more difficult. Your muscles consume more glucose, a type of sugar found in your bloodstream. This can reduce your blood sugar levels over time. It also makes the insulin in your body work better. You’ll get these benefits for hours after your walk or workout.
Just keep in mind that you don’t have to overdo it. Strenuous exercise can briefly raise blood sugar levels after you finish exercising. Extreme activity can cause the body to produce more stress hormones, resulting in an increase in blood sugar.
