Effect Of Hyperoxia Recovery After Different Intensity Training On Glucose Tolerance.

Abstract

PURPOSE: To investigate the effects of hyperoxia recovery on glucose tolerance and insulin response after high intensity interval training (HIIT) and moderate aerobic training (MIT). METHODS: The exercise intervention period was 20 min. Subjects (20.3 ± 1.3 yrs, 182.5 ± 5.8 cm, 76.6 ± 13.8 kg) were exercised at two different intensities on separated days: HIIT (repeating 2 min under 90%VO2max- 1 min rest for 7 times) and MIT (repeating 5 min under 70% VO2max- 5 min under 50%VO2max for 2 times), respectively. After training, each subjects recovered under either normaxic (21%O2) or hyperoxic (100%O2) conditions for 90 min. Oral glucose tolerance test, insulin, and cortisol were measured at baseline and during the recovery phase. Heart rate variability was recorded at baseline and 30 min after exercise. RESULTS: A significant lower glucose level was noted under HIIT condition with hyperoxia recovery comparing to normaxia (p<.05). Insulin levels during OGTT were not different under all conditions. For those subjects after HIIT, but not MIT, lower cortisol level with hyperoxia was found at 60 and 90 min after exercise. Vagal activity significantly decreased at 30 min after both exercises, yet no group difference was found. CONCLUSION: This study demonstrated that hyperoxia can improve insulin sensitivity for glucose disposal during post-exercise recovery. This effect appears to be due to a reduced cortisol response during recovery, and was not associated with autonomic nervous activity.