Published in:
01-12-2005 | Original Article
The effects of 24 weeks of moderate- or high-intensity exercise on insulin resistance
Authors:
Gary O’Donovan, Edward M. Kearney, Alan M. Nevill, Kate Woolf-May, Steve R. Bird
Published in:
European Journal of Applied Physiology
|
Issue 5-6/2005
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Abstract
This study was designed to investigate the effect of exercise intensity on insulin resistance by comparing moderate- and high-intensity interventions of equal energy cost. Maximum oxygen consumption (VO2max), insulin, glucose and triglycerides were measured in 64 sedentary men before random allocation to a non-exercise control group, a moderate-intensity exercise group (three 400-kcal sessions per week at 60% of VO2max) or a high-intensity exercise group (three 400-kcal sessions per week at 80% of VO2max). An insulin sensitivity score was derived from fasting concentrations of insulin and triglycerides, and insulin resistance was assessed using the homeostasis model assessment of insulin resistance (HOMA-IR). Data were available for 36 men who finished the study. After 24 weeks, insulin concentration decreased by 2.54±4.09 and 2.37±3.35 mU l−1, insulin sensitivity score increased by 0.91±1.52 and 0.79±1.37, and HOMA-IR decreased by −0.6±0.8 and −0.5±0.8 in the moderate- and high-intensity exercise groups, respectively. When data from the exercise groups were combined, one-way analysis of variance with one-tailed post hoc comparisons indicated that these changes were significantly greater than those observed in the control group (all P<0.05). Twenty-four week changes in insulin concentration, insulin sensitivity score and HOMA-IR were not significantly different between the exercise groups. These data suggest that exercise training is accompanied by a significant reduction in insulin resistance, as indicated by well-validated surrogate measures. These data also suggest that moderate-intensity exercise is as effective as high-intensity exercise when 400 kcal are expended per session.