GLYCEMIC AND INSULINEMIC RESPONSE TO PREEXERCISE CARBOHYDRATE FEEDINGS

The effects of preexercise hyperinsulinemia on exercising plasma gluco se, plasma insulin, and metabolic responses were assessed during 50 mi n cycling at 62% VO2max. Subjects were fed a 6% sucrose/glucose soluti on (LCHO) or a 20% maltodextrin/glucose solution (HCHO) to induce chan ges in plasma insulin. During exercise, subjects assessed perceived na useousness arid lightheadedness. By the start of exercise, plasma gluc ose and plasma insulin had increased. In the LCHO trial, plasma glucos e values significantly decreased below the baseline value at 30 min of exercise. However, by 40 min, exercise plasma glucose and insulin val ues were similar to the baseline value. Exercise plasma glucose and in sulin did not differ from baseline values in the HCHO trial. Ingestion of LCHO or HCHO was not associated with nausea or lightheadedness. It was concluded that the hyperinsulinemia induced by preexercise feedin gs of CHO did not result in frank hypoglycemia or adversely affect sen sory or physiological responses during 50 min of moderate-intensity cy cling.