Hydration and Exercise Performance in Cycling

How Does Altering the Composition of Ingested Fluids Affect Hydration Status Whilst Cycling?

This study will evaluate the effects manipulating ingested fluids can have on hydration status and cycling performance. There will be 4 different conditions.

Being dehydrated can decrease endurance exercise performance. The investigators wish to test which of three drinks is most effective at re-hydrating cyclists and if this affects performance. Subjects will undertake 4 tests: once dehydrated, once hydrated with water, once hydrated with a sports-specific drink, and once with an altered sports drink. Blood samples will be taken and expired gasses will be sampled at various time points throughout the tests for later analysis. A small amount of labelled water will be consumed with each drink, a technique which will allow us to quantify the absorption of each of the drinks.

Inclusion Criteria:

• Highly trained cyclists (vo2max >55 ml/kg/min, PPO (peak power output) > 4 w/kg)
• Training at least 4 times a week
• Females must be taking an oral contraceptive, or using the contraceptive implant

Exclusion Criteria:

• Recent history of musculoskeletal injury
• Diagnosed cardiovascular disease
• Regular use of nutritional supplements that may interfere with the protocol