Coconut water for sports

The effectiveness of fresh young coconut water on whole body rehydration, during a 2 h rehydration period following exercise-induced dehydration and on the physiological responses and cycling endurance performance in the heat was evaluated. In the first study: eight healthy male volunteers exercised at 60% of VO2max in the heat (31.l±0.03°C, 51.4±0.l% relative humidity (rh» until 3% of their body weight (BW) was lost. After exercise, the subjects sat for 2 h in a thermoneutral environment (22.5±0.1 °C; 67.0± 1.0% rh) and drank either coconut water (CW), carbohydrate electrolyte solution (CES) or plain water (PW) representing 120% of the fluid lost in three boluses. In the second study: eight cyclists cycled on a cycle ergometer at 70% VO2max until volitional exhaustion, in a climatic chamber (3 1. l±0.l °C; 69.2±0.4% rh), on three occasions separated by one week, either ingesting CW, CES or PW. During cycling, subjects ingested 3ml.kg-l body weight of fluid every 20 minutes. All drinks given were randomised. Blood samples, were taken at rest, before, during and after exercise at regular intervals throughout the rehydration period and cycle endurance performance. In the first study: the percent of body weight loss that was regained (used as index of percent rehydration) during CW, CES, and PW trials was 73±4%, 75±4% and 68±4% respectively, but was not statistically different between trials. The rehydration index, which provided an indication of how much of what was actually ingested was used for body weight restoration, was again not different statistically between trials (1. 73±0.25, 1.63±0.28 and 1.96±0.31 for CW, CES and PW respectively). In the second study: the cycling time to exhaustion in CW trial (103.7±8.5 min) was similar to the CES trial (105.8±10.8 min) but both were significantly longer (p0.05) to PW trial (70.6±5.6 min). Perceived rate of exertion was significantly higher (p0.05) during the PW trial compared to CW and CES trials but not significant at point of exhaustion. CW and CES were significantly sweeter (p0.05) than PW. In conclusion, ingestion of fresh young coconut water (CW), a natural refreshing beverage, could be used for whole body rehydration after exercise and CW was as good as ingesting CES for cycling performance in high heat and humidity, indicating the usefulness of CW as a sports drink.