DOES EXERCISE PRESERVE FAT FREE MASS DURING A VERY LOW ENERGY DIET IN PATIENTS WITH OBSTRUCTIVE SLEEP APNEA?

Abstract

Obesity is a major comorbidity of Obstructive Sleep Apnea (OSA), contributing to 58% of moderate to severe cases in adults. Very low energy diets (VLED) are effective for rapidly reducing weight however are associated with a greater fat free mass reduction compared to other energy restricted diets. Exercise may protect against this and has been shown to improve apnoea hypopnea index (AHI) independently of weight loss. We aimed to assess the feasibility and tolerability of rapid weight loss induced by VLED with or without high-intensity functional exercise in overweight and obese men with OSA. This two-arm open-label pilot randomised trial included 20 participants with a BMI of ≥27kg/m2 and moderate to severe OSA. Patients were randomised to VLED-only (VO) or VLED plus exercise (VEX) for 12-weeks. Both groups followed a VLED providing <800kcal/day for 8 weeks, followed by a 4-week refeeding period. The VEX group also participated in supervised high-intensity functional exercise training consisting of resistance and aerobic training of up to 5 days per week. A total weight loss of -14.5kg [95%CI -17.5 to -11.5] and -9.3kg FM [95%CI -11.0 to -7.6] was achieved (measured by DEXA). Fat-free mass (FFM) reduction occurred (-3.9kg [95%CI -5.5 to -2.3]), with a trend towards preservation in the VEX group. The VO group reduced AHI by 42.9%, moving from severe to moderate OSA. The VEX group’s AHI change (-32.6%) approached but did not reach the moderate category post-intervention. The VLED, with or without exercise, proved feasible and well-tolerated and demonstrated positive outcomes in body composition and AHI. The VEX group suggested a potential trend in preserving FFM compared to the VO group. These results are promising, indicating the need for a larger, definitive trial to confirm these findings and explore the impact of exercise on FFM preservation in this population.