Comparison of hot water immersion at 37.8°C with or without salt for rapid weight loss in mixed martial arts athletes. Issue 6 (18th March 2020)

• Record Type: Journal Article
• Authors: Connor, John; Shelley, Adam; Egan, Brendan
• Is Part Of: Journal of sports sciences. Volume 38:Issue 6(2020)
• Page Start: 607
• Page End: 611
• Publication Date: 2020-03-18
• Subjects: Body water -- fluid balance -- heat -- hydration -- magnesium -- sweat; Sports -- Periodicals; Sports -- Physiological aspects -- Periodicals; Sports -- Psychological aspects -- Periodicals; 612.044
• DOI: 10.1080/02640414.2020.1721231
• Languages: English
• ISSNs: 0264-0414

Abstract

ABSTRACT: Hot water immersion, known as a hot bath, is used by MMA athletes to produce rapid weight loss (RWL) by means of passive fluid loss. This study investigated the magnitude of body mass losses using a standardized hot bath protocol with or without the addition of salt. In a crossover design, eleven male MMA athletes (28.5 ± 4.6 y; 1.83 ± 0.07 m; 82.5 ± 9.1 kg) performed a 20-min immersion at 37.8°C followed by a 40-min wrap in a warm room. This bath and wrap was performed twice per visit. During one visit, only fresh water was used (FWB), and in the other visit, magnesium sulphate (1.6% wt/vol) was added to the bath (SWB). Prior to each visit, 24 h of carbohydrate, fibre, and fluid restriction was undertaken as part of the RWL protocol. Body mass losses induced by the hot bath protocols were 1.63 ± 0.75 kg and 1.60 ± 0.80 kg for FWB and SWB, respectively, and equivalent to ~2.1% body mass. Under the conditions employed, the magnitude of body mass loss in SWB was similar to FWB. However, further research should explore bathing in a temperature that is consistent with that habitually used by fighters, and/or higher concentrations of salt.