Changes In Fitness And Body Composition Accompanying Novel Exercise Regimens After Weight Loss And Maintenance

Abstract

Comprehensive weight loss and exercise programs are designed to improve health through favorable changes in body composition and fitness. While novel exercise interventions result in short-term improvements, the persistence of changes over the long-term is unclear. PURPOSE To examine changes in fitness and body composition after a 4-month weight loss intervention and 1 yr period of weight maintenance METHODS Participants were 123 women and 21 men with a mean (±SD) age of 47 ± 8 yrs and BMI of 29.9 ± 3.1 kg/m2 who were randomly assigned to a 4-month program of diet combined with:1) aerobic exercise (AER; 4 days/wk of 40 min.); 2) short-bouts of aerobic exercise (SB: 4 days/wk of 4 10-min.bouts); or 3) lifestyle activity (LA: accumulation of 30 min.moderate intensity walking each day). During weight loss, women were prescribed a low-fat diet of 12–1500 kcal/d and men were prescribed 15–1800 kcal/d. During weight maintenance, participants were prescribed an isocaloric diet and were asked to maintain prescribed activity levels. Fitness was assessed using VO2 max testing and body composition was assessed using DXA. RESULTS Weight loss averaged 7.0 ± 4.5 kg at week 16, of which 2.8 ± 3.9 kg was regained over the following year. ANOVA revealed that no differences among groups were observed in weight loss, %fat, fat mass or fat-free mass at any time-point. At month 4, greater improvements (p ≤ .05) in fitness were observed in the AER group (4.4 ±3.7 mL·kg-1·min-1) compared with SB (2.7±2.8 mL·kg-1·min-1) or LA (2.5 ± 3.2 mL·kg-1·min-1). Tukey post-hoc analyses found that the decline in fitness during weight maintenance also was significantly greater (p =.02) in the AER group (−3.0±2.8 mL·kg-1·min-1) compared with the LA group (−0.3±6.0 mL·kg-1·min-1), while the SB group's fitness declined by 2.4±2.9 mL·kg-1·min-1. CONCLUSIONS All three modes of exercise were associated with significant weight loss and favorable improvements in body composition. Participants in the traditional aerobic exercise group showed significant improvements in fitness initially, but also had the greatest declines during 1 yr follow-up. These data suggest that diet combined with traditional or novel exercise programs is an effective strategy for losing weight and improving body composition. Continuous bouts of aerobic exercise results in the greatest short-term fitness improvements; however, long-term adherence to this mode of exercise remains a challenge among overweight adults. Supported by NIH Grant RO1 DK 53907-01A1 to REA and Grant (M01RR-02719) from the GCRC program at Johns Hopkins Bayview Medical Center.