Effects of Improved Sleep Quality with Administration of Melatonin plus GABA on Total-body Skeletal Muscle Mass of Amateur CrossFit Athletes

Sleep and exercise influence each other through complex interactions. Sleep disorders incidence in athletes are high among several sports. 24 CrossFit practitioners, of both genders, between the ages of 25 and 35, presenting difficulty in initiating sleep, with a total sleep time of less than 6 hours per night, were recruited into a double-blind, randomized, placebo-controlled trial that lasted 8 weeks. Participants received capsules containing 3 mg of melatonin + 1200 mg of GABA (gamma-Aminobutyric acid) or placebo at 10:00 pm daily. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI), cortisol and testosterone levels were measured and total-body skeletal muscle mass (TBSMM) by Lee’s equation performed by two different examiners. Group melatonin + GABA gained an average of 600g of TBSMM while the control group lost 200g (p = 0.295). Both groups improve PSQI score (p = 0.007). No difference was found in cortisol and testosterone level. Although there was a difference between groups about TBSMM, it wasn’t statistically significant. Further studies will be necessary to demonstrate evidence of increased TBSMM from better sleep quality, with a larger number of participants and a longer trial.