The purpose of this study was to assess the efficacy of two different modes of exercise in an overweight and obese population over a 12-week period. Subjects: Forty-four overweight or obese individuals were recruited from a weight loss organisation. Participants were randomised into one of two groups which were matched according to age, gender and body mass index (BMI). The interventions consisted of either intermittent interval exercise (INT group), or intermittent steady-state exercise (SS group). Participants in both groups were on an identical strict caloric diet during the intervention period. Methods: Baseline and post-intervention testing consisted of the assessment of aerobic fitness, blood lipid profile, resting metabolism, body composition, vascular function, quality of life and activity levels. The exercise regime for the INT group consisted of a 1:2 min ratio of moderate intensity (70 75% V&O2peak) to low intensity exercise (40 45% V&O2peak), while the SS group exercised continuously between 50 55% V&O2peak. Total work per session was the same per group. Exercise consisted of walking/jogging twice daily for 15 mins five days per week. Eighteen participants dropped out of the study leaving 12 in the INT group and 14 in the SS group. Results: Peak oxygen uptake and exercise time to exhaustion increased significantly over time in the interventions (P <0.001). Significant positive changes occurred in several blood tests, including liver function, insulin like growth factor (IGF- 1) and lipid levels (cholesterol, triglyceride, low density lipoprotein (LDL) and very low density lipoprotein (VLDL) and coronary risk ratio, all P <0.05 over time). Additionally, uric acid and VLDL levels significantly decreased over time in the SS and INT groups, respectively (P <0.05), whereas IGF-1 levels significantly increased in the SS group over time (P <0.05). Body composition measures, including BMI, body mass, fat mass, percent of body fat, gynoid obesity and hip circumference, as well as waist circumference decreased significantly over time (P <0.05). Several components of the SF-36 quality of life questionnaire (physical function, role physical, bodily pain, general health, vitality, social function and mental health) improved significantly over time (P <0.05), while mental health also significantly improved over time in the SS group (P <0.01). Finally, anxiety and depression levels were significantly reduced over time (P <0.05). However, none of these changes over time significantly differed between the two groups. Conclusion: Both exercise interventions resulted in significant improvement over time in numerous health and fitness variables in an overweight and obese population. No significant differences were found, in the interaction term during a 2-way ANOVA, between the two groups at post-intervention. A longer intervention period, or changes to interval duration and intensities may result in more significant differences between the two training methods.
|Publication status||Unpublished - 2007|