Effects of three different water temperatures on dehydration in competitive swimmers

Abstract

Aims\ud The purpose of this study was to evaluate the effects of three different water temperatures on physiological responses (dehydration, sweat rate, urine output, rectal temperature and plasma electrolytes) of competitive athletes during a “simulated” race of 5 km in an indoor swimming pool.\ud Methods\ud Nine male competitive master swimmers swam 5 km with the water at temperatures of 23, 27 and 32 ̊C. Immediately before (Pre) and after (Post) each trial, samples of blood and urine were collected, body weight was recorded and rectal temperature was measured. The dehydration percentage and sweat rate were the highest at 32 ̊C and the lowest at 23 ̊C (23 ̊C: −0.9 ± 0.5; 27 ̊C: −1.3 ± 0.6; 32 ̊C: −2.2 ± 0.7% and 23 ̊C: 0.48 ± 0.28; 27 ̊C: 0.76 ± 0.36; 32 ̊C: 1.25 ± 0.37 l/h). The Post urine volume output was not significantly different in the three trials (23 ̊C: 122.6 ± 62.4; 27 ̊C: 78.2 ± 24.9; 32 ̊C 81.4 ± 37.0 mL). The 27 and 32 ̊C water increased the rectal temperature (Pre: 37.0 ± 0.3; Post: 37.9 ± 0.5 ̊C–Pre: 36.9 ± 0.4; Post: 38.0 ± 0.4 ̊C, respectively).\ud \ud Results\ud This study shows that dehydration, sweat rate and body temperatures simultaneously increase with the rise of water temperature during the shortest open water swimming event distance (5 km) performed at race intensity

Nutrition Considerations for Open-Water Swimming

“…Macaluso and colleagues (2011) reported increasing levels of hypohydration and core temperature when swimmers completed a 5-km time trial in three different water temperatures (23, 27, and 28 °C). Although moderate levels (2%) of dehydration were reported when swimmers completed the time trial in 32 °C water, rises in core temperature were mild (36.9 ± 0.4 to 38.0 ± 0.4 °C; Macaluso et al, 2011). Similar levels of weight loss have been seen in swimmers completing 2 hr of flume swimming at similar water temperatures (personal observations, David Gerrard, Otago University).…”

Physiological Effects of Water Temperatures in Swimming Toy Breed Dogs

“…In humans, a water temperature slightly lower than body temperature was found to decrease heart rate [20] , while water temperature higher than body temperature resulted in an increased heart rate [16] . This can be explained by the fact that swimming in water with a temperature lower than body temperature can cause peripheral vasoconstriction, resulting in increased blood pressure.…”

“…Many researchers have studied the effects of water temperature in animal models and in humans [1,[9][10][11][12][13][14][15][16] . Those reports found that low water temperature close to body temperature resulted in longer exercise compared to higher water temperature close to body temperature and very low temperature (lower than 20°C), respectively.…”

Hydration Status of Lifesaving Athletes During International Competition

“…In addition, ambient environmental temperatures may play a significant role on T C regulation during aqueous exercise (Macaluso et al, 2011;Soler et al, 2003). Therefore, the higher sweat rates may also be partially attributable to the participants still becoming accustomed to the altered climatic conditions (Hue et al, 2004).…”

“…Reportedly, sweat rates in male swimmers range between 0.33 and 2.7L·hr -1 (Cox, Broad, Riley, & Burke, 2002;Hue et al, 2004;Lemon, Deutsch, & Payne, 1989;Maughan et al, 2009;Macaluso et al, 2011;Soler, Echegaray, & Rivera, 2003) and 0.30 L·hr -1 for female swimmers (Cox et al, 2002;Maughan et al, 2009). In addition, previous research has shown sweat rates increase as water temperature (McMurray & Horvath, 1979;Macaluso et al, 2011) or exercise intensity increases (Cox et al, 2002). For example, in elite male water polo players, the demands of competition resulted in sweat rates and fluid intake more than twice that of the training environment (Cox et al, 2002).…”