Abstract
Background: Winter sports athletes experience significant cold stress during competition and training. Hot drinks may improve thermal comfort and ultimately aid performance. Previously, the effect of drink temperature in hot conditions has been heavily studied. However, there is comparatively little research relating to drink temperature and performance while exercising in cool conditions.
Objective: To evaluate the effectiveness of a hot sports drink, designed specifically for High Performance Sport New Zealand winter athletes. This thesis specifically evaluated the effect of hot sports drinks on exercise performance, thermal comfort and gastrointestinal symptoms while exercising in a cool environment.
Design: For this randomised crossover trial, fourteen recreationally active males aged 17-45 years-old were recruited. The average age of the participants was 32 years. They came from various sporting backgrounds. Participants completed four 15 min bouts of cycling outdoors on ergometers which included a 1 min sprint, then a 10 km time trial. Rate of perceived exertion, heart rate, distance covered during sprint, time trial power and time to complete were measured. In between bouts, they received 125 g of either a hot (50 °C) or cold (5 °C) sports drink. Additionally, they completed online surveys regarding gastrointestinal symptoms and thermal comfort during the 10 min recovery period between efforts, and again at the end of the trial. Following the 10 km time trial, they completed a 30 min rest period where they could drink ad libitum and completed a survey on palatability of the drinks.
Results: The hot sports drink did not improve 10 km time trial power (208 ± 50 W versus 208 ± 47 W, P=0.44) or 1 min sprint (593 ± 39 m versus 592 ± 38 m, P=0.84) performance relative to the cold sports drink. There were no differences in rate of perceived exertion (15 ± 2 versus 15 ± 2, P=0.49), thermal comfort (0 ± 1 versus 0 ± 1, P=0.59), any of the gastrointestinal symptoms, or palatability measures between the drinks. The average ambient temperature was 13°C. There was a moderate relationship (R=0.5) between preference score for the hot and change in 10 km time trial performance, which did not reach significance (P=0.10).
Conclusion: While there is no clear benefit of consuming hot sports drinks in cool conditions, there is nothing to suggest they have any negative effects. For athletes who enjoy a hot sports drink more than a cold one, there may be a small performance benefit, though more data is required to verify this. Further research is required to determine whether there is a performance benefit in colder conditions.