Physiological And Perceptual Response Of Drinking Vs Mouth Rinsing With Water During A 15-km Running Time Trial

Abstract

PURPOSE: This study examined the effects of ingesting versus mouth rinsing with water during a running time trial. METHODS: Recreationally active female runners (n = 23; 26 ± 6 y; 22 ± 3 % body fat) completed two, 15-km time trials on an outdoor course (~20°C; 87% RH) in a randomized cross-over study design. Participants consumed 355 ml of water (CW) or mouth rinsed (MR) with water every 3-km for 5 s. Completion time, HR, RPE, sweat loss, pre-and post-run ratings of perceived thirst, and gut fullness were measured. RESULTS: Sweat losses were greater (p = 0.01) for CW (1.6 ± 0.6 L) compared to MR (1.2 ± 0.3 L), however did not alter performance (79.8 ± 7.0 min and 79.7 ± 7.1 min, p = 0.64), HR (181 ± 15 and 179 ±13 bpm, p = 0.44), or RPE (16 ± 2 and 16 ± 2, p = 0.97). Perceived thirst did not differ before run (3.6 ± 1.8 and 4.1 ± 1.5 for CW and MR), but was higher (p = 0.02) for MR (6.8 ± 1.1) compared to CW (5.8 ± 2.0) post-run. No difference in post-run GF (5 ± 1.7 and 4.7 ± 1.4, p = 0.85, for CW and MR) was observed. CONCLUSION: MR may reduce sweat volume versus CW when running for >1 h in temperate and humid environments, but does not impair performance or induce significant cardiovascular drift in female runners who begin exercise euhydrated. A MR strategy may reduce gastrointestinal distress for runners who do not like drinking during runs and allow for a reduction in volume of water carried.