How Does Altering the Composition of Ingested Fluids Affect Hydration Status Whilst Cycling?
Trial Snapshot
- Phase
- Not Applicable
- Status
- Completed
- Sponsor
- University of Exeter
- Enrollment
- 15
- Locations
- 1
- Primary Endpoint
- Absorption of fluid through the gut
Study Overview
Brief Summary
This study will evaluate the effects manipulating ingested fluids can have on hydration status and cycling performance. There will be 4 different conditions.
Detailed Description
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.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Crossover
- Primary Purpose
- Treatment
- Masking
- Double (Participant, Investigator)
Masking Description
Doubly-blinded & randomised using an online randomisation website.
Eligibility Criteria
- Ages
- 18 Years to 50 Years (Adult)
- Sex
- All
- Accepts Healthy Volunteers
- Yes
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
Arms & Interventions
Dehydrated
90 minutes cycling, without the ingestion of any fluids, followed by a 15 minute cycling time trial test
Intervention: Dehydrated (Other)
Hypotonic
90 minutes cycling, with the ingestion of six 250 ml carbohydrate (6g sucrose, 3g glucose) drinks, followed by a 15 minute cycling time trial test
Intervention: Hypotonic (Dietary Supplement)
Isotonic
90 minutes cycling, with the ingestion of six 250 ml carbohydrate (6g glucose, 3g fructose) drinks, followed by a 15 minute cycling time trial test
Intervention: Isotonic (Dietary Supplement)
Placebo
90 minutes cycling, with the ingestion of six 250 ml taste-matched water drinks, followed by a 15 minute cycling time trial test
Intervention: Placebo (Dietary Supplement)
Outcomes
Primary Outcomes
Absorption of fluid through the gut
Time Frame: To begin 10 minutes after the completion of the 90 minute steady-state cycle
Absorption of drinks through the gut will be measured using 2 boluses of deuterated water. This will be consumed alongside 2 of the drinks, and blood samples will be used to quantify enrichment. Total body water calculations are required to provide corrections in equations related to D2O. H218O will be consumed in order to quantify total body water: this will be provided in a single bolus before each trial.
Secondary Outcomes
- Work done (kJ) during 15 minute cycling time-trial(Throughout the 90 minute steady-state cycle & the 15 minute time trial.)