Hydration and Exercise Performance in Cycling

Not Applicable

Completed

• Conditions: Healthy
• Interventions: Dietary Supplement: Hypotonic; Dietary Supplement: Placebo; Dietary Supplement: Isotonic; Other: Dehydrated

• Registration Number: NCT03304197
• Lead Sponsor: University of Exeter

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 Timeline

• Study Start: 2017-09-11
• Study First Submitted: 2017-09-13
• Study First Submitted QC: 2017-10-02
• Study First Posted: 2017-10-06
• Primary Completion: 2018-06-01
• Study Completion: 2018-06-01
• Status Verified: 2018-10
• Last Update Submitted: 2018-10-11
• Last Update Posted: 2018-10-12

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 15

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

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Exclusion Criteria

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

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Hypotonic	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
Placebo	Placebo	90 minutes cycling, with the ingestion of six 250 ml taste-matched water drinks, followed by a 15 minute cycling time trial test
Isotonic	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
Dehydrated	Dehydrated	90 minutes cycling, without the ingestion of any fluids, followed by a 15 minute cycling time trial test

Primary Outcome Measures

Name	Time	Method
Absorption of fluid through the gut	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 Outcome Measures

Name	Time	Method
Work done (kJ) during 15 minute cycling time-trial	Throughout the 90 minute steady-state cycle & the 15 minute time trial.	Subjects will perform a cycle ergometer protocol that has been shown to be reproducible in athletes. Subjects will complete the time trial on a Lode Excalibur cycling ergometer. Software linked to this software will record work done and power output.

Trial Locations

Locations (1)

School of Sports and Health Sciences; 🇬🇧 Exeter, Devon, United Kingdom