INVESTIGATION OF INSULIN SENSITIVITY IN EARLY DIABETES .3. THE EFFECT OF A COMBINED PHYSICAL-TRAINING AND DIET PROGRAM ON BODY-WEIGHT, SERUM-LIPIDS AND INSULIN SENSITIVITY IN OBESE ASYMPTOMATIC DIABETICS

  • 1 January 1981
    • journal article
    • research article
    • Vol. 77  (2) , 233-241
Abstract
The effect of a physical training and low caloric diet (700 calories/day) for 4 wk on insulin sensitivity in vivo, body weight and serum lipids was investigated in 10 obese asymptomatic diabetics (normal fasting plasma glucose and pathological glucose tolerance). Glucose tolerance and insulin secretion pattern were characterized by means of a 2 h glucose infusion test (12 mg/kg per min) primed by an initial injection of 0.33 g/kg glucose. Insulin responsiveness in vivo was estimated by means of a 1 h insulin infusion test (two 30 min periods of 8 and 16 mU/kg insulin MC-Actrapid, primed by initial injection of 1 and 2 mU/kg, respectively). Under comparable steady-state insulin levels the decrease in plasma glucose and free fatty acids (FFA) was considered as estimate of insulin sensitivity in vivo. Physical working capacity (PWC170) was determined by means of a bicycle ergometer test in stepwise working loads. The training program consisted of daily 15 min bicycle ergometer training periods (75% of the maximal working capacity) in the morning and a 1 h mild physical training on a bicycle in the afternoon. After the combined training and diet program the mean decrease in absolute and relative body weight amounted to 11.9 .+-. 1.07 kg and 16.7 .+-. 1.2%, respectively. There was a significant decrease of plasma triglycerides; the decrease in cholesterol was modest. Physical fitness increased by .DELTA. PWC170 of 31.1 .+-. 11.6 W. The combined training and diet program for 4 wk resulted in a significant improvement of insulin sensitivity in vivo as indicated by an augmented insulin-induced decrease in plasma glucose and FFA (17.60 .+-. 3.91% vs. 36.40 .+-. 5.54%; P < 0.05 and 35.90 .+-. 6.95% vs. 56.50 .+-. 3.63%; P < 0.05; respectively). Physical training and low caloric diet enhance insulin sensitivity in vivo. The potential benefits of physical training in the treatment of obese asymptomatic diabetics are suggested.