Too high blood sugar levels can attenuate the usefulness of exercise, especially aerobic exercise, according to a new study by researchers at the Joslin Diabetes Center.
Hyperglycaemia is a condition that sees too high blood sugar levels and is often linked to diabetes.
To reach this conclusion, the researchers once again carried out experiments on mice. Specifically, they used rats with a condition very similar to that of chronic hyperglycemia in humans, a condition that can be common in the so-called “prediabetes”, a phase that precedes the condition of diabetes itself.
They divided the mice into two groups: one following a western type diet, rich in sugars and fats, and another group made from mice modified to produce less insulin, which increased blood sugar, similarly to what occurred with the western diet in the mice of the first group.
Both groups of mice then had to undergo training by running on wheels inside the cages.
The researchers realized that mice with higher sugar levels were unable to improve their aerobic exercise capacity even after hundreds of km traveled. In practice, training had little effect on them.
Looking at their bodies in more detail, the researchers saw that the muscles could not adapt well to aerobic effort as a muscle normally does when it is always subjected to the same exercise, which then makes the exercise easier.
According to the scientists, higher levels of blood sugar somehow prevent muscle remodeling by modifying, at least in part, the proteins of the “extracellular matrix” in the space between the cells of the same muscles, spaces where blood vessels are formed .
“As a result, the muscles of hyperglycemic animals have larger fibers and fewer blood vessels, which is more typical of strength training rather than aerobic training,” explains Sarah Lessard, senior author of the study published in Nature Metabolism.