Effect of rapid weight loss in combat sports: systematic review

Background & Study Aim: Rapid weight loss (RWL) is a process usually practiced by combat athletes. The objective of this review was to know the effects of RWL on cardiac response, executive functions, and mood state, as well as the study methodologies used. Material & Methods: The search was conducted in Web of Science, Scopus, PubMed, and Google Scholar, in English and Spanish from 2015 to 2022 using the keywords: "rapid weight loss", "acute weight loss", "RWL", "heart rate variability", "HRV", "sympathetic response", "sympathetic cardiac modulation", "executive functions", "cognition", "cog- nitive", "mood states", and "combat sports". Articles where athletes practiced RWL were included, and the amount of weight lost and at least one variable of interest were reported, considering criteria 1, 10 and 11 of the Spanish's version of the PEDro scale and the PRISMA guidelines. Results: Seven articles reported an increased heart rate; in terms of executive performance, no significant effects on inhibitory control and reaction time were reported in two articles. Finally, seven articles reported, an increase in tension, depression, anger and fatigue, and a decrease in vigour. Conclusions: No papers evaluating simultaneously all three variables of interest were found. The effects of RWL appear to be unclear in the analysed articles used, considering the diversity in the methodologies used, it is recommended to carry out studies involving biopsychosocial factors, such as the level of sports and competitive experience of the participants; as well as having standard indicators and methodologies to know the real effect of RWL.