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Completed

NCT Number: NCT03304197

Hydration and Exercise Performance in Cycling

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

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Key information

Conditions

Healthy

Age range

18 year–50 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

School of Sports and Health Sciences

Exeter, Devon, EX1 2LU, United Kingdom

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Hypotonic

Dietary Supplement

N/A: see arm description

Isotonic

Dietary Supplement

N/A: see arm description

Placebo

Dietary Supplement

N/A: see arm description

Dehydrated

Other

N/A: see arm description

Primary outcomes

  1. 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

  1. Work done (kJ) during 15 minute cycling time-trial

    Time frame: 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.

Other outcomes

  1. Substrate utilisation

    Time frame: Throughout the 90 minute steady-state cycle

    Substrate utilisation will be calculated from data collected through a metabolic cart and its software. It will be measured during the 90-minute steady-state cycle for 4 periods of 3 minutes. Carbohydrate and lipid oxidation rates will be calculated using equations by Jeukendrup & Wallis (2005).

  2. Plasma metabolites

    Time frame: Throughout the 90 minute steady-state cycle and time-trial

    A cannula will be used to draw blood from subjects at several time points. Whole blood samples will be analysed immediately for plasma glucose, plasma lactate, haemoglobin content, haematocrit and plasma volume. Remaining whole blood will be centrifuged immediately and its plasma split into aliquots and stored in a -20°C freezer. At the end of the trial, plasma samples will be moved to a -80°C freezer for later analysis for sodium, glycerol, and NEFA.

  3. Heart rate

    Time frame: Throughout the 90 minute steady-state cycle and time-trial

    Heart rate will be measured throughout with the use of a heart rate monitor.

  4. RPE (rating of perceived exertion)

    Time frame: Throughout the 90 minute steady-state cycle and time-trial

    RPE will be measured using the Borg Scale.

  5. Core body temperature

    Time frame: Throughout the 90 minute steady-state cycle and time-trial

    Core temperature will be measured throughout with the use of an ingestible core-body temperature pill (HQ Inc, FL, USA).

Sponsors and collaborators

Lead sponsor

University of Exeter

Other

Registry information

Official study title

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

Important dates

Study start
2017
Primary completion
2018
Study completion
2018
First posted
Oct 6, 2017
Registry last updated
Oct 12, 2018

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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