Every doctor recommends regular aerobic exercise, since greater aerobic fitness is important for achieving better overall health. But Joslin Diabetes Center scientists now have discovered that some benefits of aerobic exercise may be dampened by higher-than-normal blood sugar levels, a condition known as hyperglycemia.
These diminished gains are seen in mouse models and humans with chronic hyperglycemia that is in the “prediabetes” range, says Sarah Lessard, PhD, a Joslin assistant investigator in the section of Clinical, Behavioral and Outcomes Research and senior author on a paper in Nature Metabolism that presents the work. The study also showed that this maladaptive trait is independent of obesity and insulin levels in the blood.
Clinical studies have demonstrated that people with diabetes or chronically high levels of blood sugar struggle to improve their aerobic exercise capacity compared to people with normal blood sugar levels. “The idea behind this study was to see if we induce high blood sugar in mice, will we impair their ability to improve their aerobic fitness?” says Lessard, who is an assistant professor of medicine at Harvard Medical School. The study also aimed to uncover the mechanisms that may lead to low fitness levels in people with hyperglycemia.