Exploring the feasibility of concurrent exercise training on body composition during rapid weight loss in men with overweight or obesity and obstructive sleep apnoea

Abstract

This thesis aimed to assess the feasibility and tolerability of a very low energy diet (VLED) induced weight loss intervention with or without exercise training in men with obstructive sleep apnoea (OSA) and overweight or obesity.

Firstly, a systematic review and meta-analysis was conducted to assess the strength of evidence for the impact of exercise on fat free mass (FFM) reduction during VLED-induced weight loss in adults with overweight or obesity. This was followed by a 12-week open label, pilot randomised controlled trial that randomised participants to either VLED-only (VO) or VLED plus exercise (VEX). The VLED provided <800kcal/day. Exercise was supervised and performed at a commercial gym following a ramped protocol containing aerobic and resistance training. Outcomes were measured at baseline and 12 weeks.

Twenty men aged 18-55 years with a BMI of ≥27kg/m2 and untreated moderate to severe OSA were randomised to VO (n=9) or VEX (n=11). All were followed up at 12 weeks with one drop out from the VEX group. Both groups showed similar adherence to VLED as well as significant reductions in weight, fat mass, FFM, and apnoea hypopnoea index (AHI). A small but non-significant preservation of FFM occurred in the VEX group. No between group differences were observed for any outcomes.

The protocol was found to be feasible and acceptable and the interventions safe and tolerable. Both groups had statistically and clinically significant reductions in weight and AHI. The addition of exercise had a small preserving effect on FFM though this was not significantly different from VLED alone. The small sample size limited the ability to detect between group differences and potentially by the difference in body weight observed between groups at baseline. A larger study is needed to determine the protective effect of exercise on FFM during VLED-induced weight loss in this population. Based on these findings, such a trial would be feasible and tolerable for those enrolled.