While physical exercise is essential for maintaining good health, its benefits can be reduced or even canceled out by high blood sugar levels.
- Research in mice has shown that abnormally high blood sugar levels diminish the beneficial effects of aerobic exercise on physical fitness.
- The reason: muscles that are less well vascularized, and therefore less well oxygenated.
Practicing physical activity is not only good for morale, but also for fitness: many studies have indeed demonstrated the importance of aerobic exercise on general health.
However, these benefits must be supported by a healthy diet because, in the event of hyperglycemia, that is to say in the case of abnormally high and chronic levels of sugar in the blood, they can be greatly reduced.
This is revealed by a study conducted at the Joslin Diabetes Center in Boston (USA) and published in Nature Metabolism. According to its authors, who observed this decrease in gains from aerobic exercise in mice and humans, high blood sugar levels have consequences for physical fitness. They also found that people with high blood sugar had lower than average fitness levels.
Difficulty improving physical condition
To reach these conclusions, the scientists used two mouse models with high blood sugar levels. A first group of mice followed a Western diet, high in sugar and saturated fat, which caused some weight gain in addition to hyperglycemia. The other group was genetically engineered to produce less insulin, which caused increases in blood sugar similar to the Western diet, even though the mice were fed a diet lower in sugar and fat, and maintained normal body weight. Both groups were then put through a training protocol in which they ran on wheels in their cages to improve their aerobic condition.
In total, the rodents ran about 500 kilometers during the study but still failed to improve their aerobic exercise capacity compared to mice that were not hyperglycemic.
Less well vascularized muscles
How to explain it? By examining the skeletal muscle in more detail in these mice, the researchers found that the muscle tissue was less vascularized, which explains why the level of aerobic fitness did not increase. The study authors therefore concluded that high blood sugar levels can prevent muscle remodeling.
This conclusion was confirmed in clinical tests on young adults. Volunteers with higher blood sugar levels after glucose ingestion also showed lower aerobic exercise capacity.
“The good news is that although our hyperglycemic mouse models failed to improve aerobic fitness with training, they still achieved other important health benefits from exercise, including decreased fat mass and improved glucose metabolismnuance Sarah Lessard, lead author of the study. Thus, regular aerobic exercise remains a key recommendation for maintaining health in people with or without hyperglycemia..”
According to her, these results show that it is possible for people with chronic hyperglycemia to increase their aerobic exercise capacity, in particular by adopting a diet with low blood sugar levels, or by taking diabetes medication. specially designed to maintain blood sugar levels within normal limits. “We often see diet and exercise as separate ways to improve our healthexplains Mr. Lessard. But our work shows that there is more interaction between these two lifestyle factors than previously known, and suggests that we may want to consider them together in order to maximize the benefits of aerobic exercise. for health.”
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