Effect of Mild Exercise Training on Glucose Effectiveness in Healthy Men

Abstract

OBJECTIVE—To detect whether mild exercise training improves glucose effectiveness (SG), which is the ability of hyperglycemia to promote glucose disposal at basal insulin, in healthy men. RESEARCH DESIGN AND METHODS—Eight healthy men (18–25 years of age) underwent ergometer training at lactate threshold (LT) intensity for 60 min/day for 5 days/week for 6 weeks. An insulin-modified intravenous glucose tolerance test was performed before as well as at 16 h and 1 week after the last training session. SG and insulin sensitivity (SI) were estimated using a minimal-model approach. RESULTS—After the exercise training, Vo2max and Vo2 at LT increased by 5 and 34%, respectively (P < 0.05). The mild exercise training improves SG measured 16 h after the last training session, from 0.018 ± 0.002 to 0.024 ± 0.001 min−1 (P < 0.05). The elevated SG after exercise training tends to be maintained regardless of detraining for 1 week (0.023 ± 0.002 min−1, P = 0.09). SI measured at 16 h after the last training session significantly increased (pre-exercise training, 13.9 ± 2.2; 16 h, 18.3 ± 2.4, ×10−5 · min−1 · pmol/l−1, P < 0.05) and still remained elevated 1 week after stopping the training regimen (18.6 ± 2.2, ×10−5 · min−1 · pmol/l−1, P < 0.05). CONCLUSIONS—Mild exercise training at LT improves SG in healthy men with no change in the body composition. Improving not only SI but also SG through mild exercise training is thus considered to be an effective method for preventing glucose intolerance.