Effects Of Exercise Training Amount And Intensity On Metabolic Syndrome

Abstract

Exercise is beneficial for the individual risk factors of metabolic syndrome (MetSyn) defined by revised ATP III criteria. However, as the clinical definition of MetSyn is relatively new, there is little research on the effect of exercise on the syndrome as a whole, specifically the effects of different amounts and intensities of exercise. METHODS: Of 387 subjects recruited for STRRIDE, 199 (93 women, 106 men) finished, had data for at least four of five risk factors, and were included in this analysis. Subjects were randomly assigned to six-month control or one of three eight-month exercise training groups: 1) high-amount/vigorous-intensity (calorically equal to 20 miles jogging/wk); 2) low-amount/vigorous-intensity (equal to 12 miles jogging/wk); 3) low-amount/moderate-intensity (equal to 12 miles walking/wk). Results: Analysis of variance shows a significant beneficial effect of exercise on MetSyn compared to the inactive control group, as the effects of all exercise groups were significantly better than controls (see figure). To determine if this difference was due to the detrimental effects of sedentary living, or to the ability of exercise to improve MetSyn, or both, paired t-tests on the individual effects of each group were performed (see figure). Metabolic syndrome scores deteriorated in controls (P=0.08). The lower amount of exercise at the moderate, but not vigorous intensity, significantly improved MetSyn score, suggesting that lower intensity exercise may be more effective than higher intensity exercise. The higher amount of vigorous intensity exercise also significantly improved MetSyn, indicating a dose-response relationship for vigorous intensity exercise. That is, some vigorous exercise is better than none, more vigorous exercise is better than less.FigureConclusion: MetSyn score in the control group worsened, although this effect was just on the border of statistical significance. Exercise, compared to sedentary living, beneficially affected MetSyn. The data, taken as a whole, suggest that lower intensity exercise may be more effective than more vigorous exercise and lends support to the 1995 CDC/ACSM recommendation that adults get 30 min of moderate intensity exercise most every day. The data also support a dose-response relationship for vigorous exercise, indicating that while some exercise is beneficial, more exercise (i.e. more kcals expended per week) was better.