Schneider S H, Khachadurian A K, Amorosa L F, Gavras H, Fineberg S E, Ruderman N B
Division of Endocrinology, Metabolism and Nutrition, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, New Brunswick 08903-0019.
Metabolism. 1987 Dec;36(12):1161-6. doi: 10.1016/0026-0495(87)90243-5.
We studied the effects of exercise on the levels of plasma glucose and glucoregulatory hormones before and after 6 weeks of thrice-weekly physical training in 20 sedentary type II (non-insulin-dependent) diabetic patients and 11 control subjects matched for previous physical activity. Parameters were measured at rest, after 30 minutes of bicycle exercise at 70% to 75% of maximal oxygen uptake, and after 30 minutes of recovery. In the untrained state exercise resulted in a decrease in plasma glucose levels in diabetics but not in controls (-12 +/- 5 v + 4 +/- 2 mg/dL, P less than .01) and the expected drop in plasma insulin level was absent in diabetics. These differences in glucose and insulin response persisted after physical training. There was a tendency for patients with diabetes to have a smaller R-R interval variation during deep breathing, an abnormal resting heart rate response to physical training, and a lesser increment in plasma epinephrine levels following exercise, findings consistent with autonomic dysfunction. Physical training resulted in a blunting of the exercise-induced increment of plasma epinephrine, growth hormone, and lactate levels in control subjects, but not in diabetics. Our data demonstrate a hypoglycemic effect of exercise in mildly hyperglycemic nonobese type II diabetics. Possible causative factors include: hyperglycemia per se, a lack of physiologic suppression of plasma insulin, and abnormalities of autonomic or hypothalamic regulatory function.
