Effects of Exercise Training Modalities on Fat Oxidation in Overweight and Obese Women

Abstract

Purpose: To compare the effects of aquatic-based and land-based exercise training on fat oxidation in overweight and obese women. Methods: Twenty healthy, overweight and obese women were randomly assigned to, and completed endurance training; deep water running (DWR) (n = 11, age 48 +/- 7 years, BMI 30.0 +/- 4.0 kg/m2), or endurance training combined with resistance training (DWR+RT) (n = 9, age 48 +/- 8 years, BMI 29.7 +/- 4.1 kg/m2) three times per week (70% mode specific HRpeak) for 12 weeks. Following the 12 week intervention there was an eight month washout period. At the end of the washout period, 17 of the 20 women originally enrolled in the first intervention participated in, and completed a second intervention, undertaking the same protocol as in the first study, in a land-based environment. Two additional participants recruited, were randomly assigned to, and completed respective land-based training. Nineteen participants in total completed endurance training; land based endurance (LBE) (n = 9, age 49 +/- 7 years, BMI 30.0 +/- 3.8 kg/m2), or endurance training combined with resistance training (LBE+RT) (n = 10, age 49 +/- 7 years, BMI 29.4 +/- 4.0 kg/m2) three times a week (70% mode specific HRpeak) for 12 weeks. Results from seventeen participants who completed both the aquatic and land-based interventions were pooled for analysis to compare aquatic-based and land-based exercise training modalities. For the aquatic and land-based interventions, pre and post intervention outcome measures included; resting and exercise fat oxidation and resting metabolic rate (RMR) measured by indirect calorimetry, resting and exercise plasma free fatty acid (FFA) and glycerol concentrations, cardiovascular (CV) fitness assessed during mode specific maximal oxygen consumption (VO2peak) tests, upper and lower body strength using a Biodex Isokinetic Dynamometer, body composition using dual-energy X-ray absorptiometry (DXA) and anthropometry, and plasma lipid profiles. Statistical analysis included between-group comparisons of outcome measures using analysis of covariance (ANCOVA). When there was no difference between groups, data was pooled and within modality comparisons were assessed by Student’s paired t-test. Pearson correlation coefficients were used to investigate relationships between outcome measures. Results: Exercise fat oxidation rate did not change following DWR or DWR+RT, or aquatic exercise training overall (p > 0.05). Following land-based exercise training, when training groups were combined, participants demonstrated significant increases in exercise fat oxidation rate (300 +/- 92 to 359 +/- 119 mg/min; p < 0.01), with no difference between LBE and LBE+RT (p < 0.05). When aquatic exercise training was compared directly with land-based exercise training using pooled analysis, there were significantly different responses pertaining to changes in exercise fat oxidation rate (p = 0.03). There was a significant increase in exercise fat oxidation rate following land-based exercise training (310 +/- 91 to 373 +/- 118 mg/min; p < 0.01); however, no change was observed following aquatic exercise training (265 +/- 109 to 264 +/- 73 mg/min; p = 0.97). Conclusion: Overweight and obese healthy women demonstrate an increase in exercise fat oxidation rate following land-based exercise training, but not aquatic-based exercise training.