Exercise hypoglycemia in nondiabetic subjects.

Hypoglycemia during exercise is a common event due to an unbalance between training volume, nutrition, and external influences such as chronobiology, temperature or altitude, in subjects characterized by an acute and chronic increase in glucose effectiveness and insulin sensitivity. While it is preventable by adequate pre-exercise feeding with carbohydrates, it can also be induced by a prior carbohydrate meal with high glycemic index. Adequate training induces resistance to hypoglycemia via a shift in the balance of oxidized substrates and marked hormonal adaptations, but overtraining, by partially reversing this adaptation, favorizes hypoglycemia. Exercise hypoglycemia is a cause of fatigue or exercise cessation, but also impairs thermoregulatory adaptation and is assumed to fragilize muscles and tendons for traumatic events.