This article looks at hydration during cycling in the heat
What’s the deal?
We sweat more when exercising in the heat which can lead to a decline in performance. How much water should we drink to counteract this, how often, and do we know what’s best for us?
What did they do?
Ten athletes completed two cycling-based tests in the heat, at least 1 week apart. Each test consisted of 3 sets of cycling for 5km at 50% effort, followed by 5km at maximum effort on a slight hill. During one test, athletes were allowed to drink water as they chose (ad libitum), whereas during the other test, athletes were given a set amount of water at each km corresponding to the predicted amount of sweat they would lose.
What happened?
When athletes drank water ad libitum they became dehydrated over the three sets of cycling, whereas athletes who were given a set amount did not. In addition, athletes were able to maintain cycling speed during the whole test when given a set amount of water, but ad libitum drinking led to a decline in performance during the final set.
What can you tell me about the people?
All athletes were male, aged 30 years on average, and were very experienced cyclists. Cyclists were allowed to use their own bike mounted to a stationary turbo trainer.
What else should I know?
The tests were carried out indoors with the temperature set to 31-32°C (about 89°F). Predicted sweat loss and dehydration were calculated based on body weight changes during a preliminary cycling test.
What will I do differently?
It seems that we cannot be trusted to drink enough water during exercise to keep ourselves hydrated. I frequently weigh myself before and after long runs and have often lost multiple kgs (3 lbs+), most likely affecting my performance. Perhaps it’s time I get scientific with my rehydration tactics!
Acknowledgements
This research was published in June 2017 by CN Bardis and colleagues from Harokopio University in Athens, Greece.
This article highlights our personal take on their research, but there is so much more information available! Check it out here and see what you think!
Abstract Athlete 