Post-exercise Rehydration: A Randomised Cross-over Trial Comparing a 100% Fruit Beverage, a Glucose-based Sports Drink, and Water

Comparing The Rehydration Properties Of Two Sports / Hydration Drinks And Water, Following Exercise In The Heat

It is well-established that exercise has many health benefits. During exercise in temperate/hot conditions, sweating is necessary to dissipate heat. This sweating typically results in dehydration, which may impair physical and mental performance. Therefore, following exercise, effective rehydration is important to restore an optimal hydration state and therefore physical and mental performance. If an individual only rehydrates with water, though, it is unlikely that they will fully rehydrate as plain water is not very well-retained by the body, due to its lack of carbohydrate and electrolytes. For this reason, sports/ hydration drinks are likely to aid in better rehydration, due to their carbohydrate and electrolyte content. This project aims to compare the rehydration effectiveness and glucose responses to two sports / hydration drinks and water (with different carbohydrate and electrolyte contents).

Study Overview

• Status: Completed
• Conditions: Dehydration
• Intervention / Treatment: Other: Water; Other: Glucose-based sports drink; Other: Fruit beverage

• Study Type: Interventional
• Enrollment (Actual): 17
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • Nottingham, United Kingdom, NG11 8NS
    • Nottingham Trent University, Clifton Campus

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

- Training/performing > 1 hrs a week

Exclusion Criteria:

• Smoker.
• Pregnant, attempting to become pregnant, or breastfeeding.
• Diabetic.
• You have adverse events/reactions in response to fingertip capillary blood sampling which includes, but is not limited to; fainting and/or serious bruising.
• History of heat-related illness.
• History of heart failure, pulmonary hypertension, embolism, or other pulmonary heart disease.
• Previously diagnosed with COPD, emphysema, bronchitis or similar respiratory illness.
• Have a history of severe allergic reactions.
• History of kidney issues.
• Regular use of non-steroidal anti-inflammatory medications.
• Any other medical conditions / medications that may interfere with an individuals ability to safely perform exercise in the heat and experience dehydration.
• Allergies/intolerances to any of the following ingredients: Glucose Syrup, Acid (Citric Acid), Acidity Regulator (Sodium Citrate), Extract of Black Carrot, Watermelon, pomegranate, lime, Preservatives (Potassium Sorbate, Dimethyl Dicarbonate), Stabilisers (Acacia Gum), Sweeteners (Aspartame, Acesulfame K), Antioxidant (Ascorbic Acid), Flavourings, Niacin (Vitamin B3).
• Elite athlete subject to doping tests

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Water; Consumption of a water volume (from water) equal to 150% of body mass loses from exercise-induced hypohydration	Other: Water; Consumption of a water volume (from water) equal to 150% of body mass loses from exercise-induced hypohydration
Experimental: Glucose-based sports drink; Consumption of a water volume (from a glucose-based sports drink) equal to 150% of body mass loses from exercise-induced hypohydration	Other: Glucose-based sports drink; Consumption of a water volume (from a glucose-based sports drink) equal to 150% of body mass loses from exercise-induced hypohydration
Experimental: Fruit beverage; Consumption of a water volume (from a fruit beverage) equal to 150% of body mass loses from exercise-induced hypohydration	Other: Fruit beverage; Consumption of a water volume (from a fruit beverage) equal to 150% of body mass loses from exercise-induced hypohydration

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Net water Balance	([post-exercise body mass (kg) - Pre-exercise body mass (kg)] x 1000) + water volume consumed (g) - cumulative urine output during rehydration period (g)	Baseline (pre-exercise), post-exercise, and 0, 1, 2, 3, and 4 h post-rehydration
Cumulative urine volume		0, 1, 2, 3, and 4 h post-rehydration
Total urine volume	Total urine volume produced during the rehydration period	Sum of urine produced at 0, 1, 2, 3, and 4 h post-rehydration
Water retention	([water volume consumed (g) - total urine volume produced during the rehydration period (g)] / water volume consumed (g)) x 100	4 h post-rehydration

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Blood glucose concentration		Baseline (pre-exercise), post-exercise, and 0, 0.25, 0.5, 0.75, 1, 1.5, and 2 h post-rehydration
Blood glucose area under the curve		The 2h period following rehydration
Hyperglycaemia incidence	Number of participants that experience blood glucose > 7.8 mmol/L	The 2 h period following rehydration
Hypoglycaemia incidence	The number of participants that experience blood glucose < 3.9 mmol/L	The 2 h period following rehydration
Urine osmolality	A measure of urine concentration.	Baseline (pre-exercise), post-exercise, and 0, 1, 2, 3, and 4 h post-rehydration
Body mass	Body mass in kilograms at baseline compared across trials. Body mass loss (both in grams and as a percentage) from pre-exercise to post-exercise compared across trials.	Baseline (pre-exercise) and post-exercise (approximately 2 h post-baseline, depending on sweat losses during cycling in the heat)
Thirst	Participants asked to rate their thirst on a scale of 0-10 (0 = no symptom, 10 = maximum symptom)	Baseline (pre-exercise), towards the end of each 10 minute block of exercise (cycling in the heat), post-exercise, and 0, 1, 2, 3, and 4 h post-rehydration
Gastrointestinal comfort	Participants asked to rate their gastrointestinal comfort on a scale of 0-10 (0 = no symptom, 10 = maximum symptom)	Baseline (pre-exercise), post-exercise, and 0, 1, 2, 3, and 4 h post-rehydration
Rating of perceived exertion (RPE)	Participants asked to rate their RPE on a scale of 6-20. This is a measure of exercise intensity. Average taken for dehydration period. Average compared across trials.	Measured towards the end of each 10 minute block of exercise (cycling in the heat). Up to 8 blocks lasting a total of 120 minutes (10 minutes of cycling, followed by 5 minutes of rest), depending on body mass loss.
Thermal sensation	Participants asked to rate their thermal sensation on a scale of -10 (unbearably cold) to 10 (unbearably hot). Average taken for dehydration period. Average compared across trials.	Measured towards the end of each 10 minute block of exercise (cycling in the heat). Up to 8 blocks lasting a total of 120 minutes (10 minutes of cycling, followed by 5 minutes of rest), depending on body mass loss.
Time in environmental chamber	The time in minutes that the participant spent in the environmental chamber at 35 degrees Celsius, doing repeated blocks of 10 minutes of cycling followed by 5 minutes of rest, until they reached approximately 1.5% body mass loss. Time compared across trials.	Up to 120 minutes, depending on body mass losses during cycling in the heat
Laboratory temperature	Temperature (degrees Celsius) of the laboratory measured across the day and averaged. Averages compared across trials.	Baseline (pre-exercise), post-exercise, and 0, 1, 2, 3, and 4 h post-rehydration
Environmental chamber temperature	Environmental chamber temperature (degrees Celsius) measured and averaged for the cycling in the heat period of each participant. Averages compared across trials.	Measured towards the end of each 10 minute block of exercise (cycling in the heat). Up to 8 blocks lasting a total of 120 minutes (10 minutes of cycling, followed by 5 minutes of rest), depending on body mass loss.
Laboratory humidity	Humidity (relative humidity) of the laboratory measured across the day and averaged. Averages compared across trials.	Baseline (pre-exercise), post-exercise, and 0, 1, 2, 3, and 4 h post-rehydration
Environmental chamber humidity	Environmental chamber humidity (relative humidity) measured and averaged for the cycling in the heat period of each participant. Averages compared across trials.	Measured towards the end of each 10 minute block of exercise (cycling in the heat). Up to 8 blocks lasting a total of 120 minutes (10 minutes of cycling, followed by 5 minutes of rest), depending on body mass loss.

Collaborators and Investigators

• Sponsor: Nottingham Trent University
• Collaborators: Innate-Essence Limited

Study record dates

Study Major Dates

• Study Start (Actual): November 8, 2024
• Primary Completion (Actual): May 22, 2025
• Study Completion (Actual): May 22, 2025

Study Registration Dates

• First Submitted: March 3, 2026
• First Submitted That Met QC Criteria: March 9, 2026
• First Posted (Actual): March 12, 2026

Study Record Updates

• Last Update Posted (Actual): March 12, 2026
• Last Update Submitted That Met QC Criteria: March 9, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Metabolic Diseases; Water-Electrolyte Imbalance; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Dehydration; Inorganic Chemicals; Anions; Ions; Electrolytes; Hydroxides; Alkalies; Oxides; Oxygen Compounds; Water
• Other Study ID Numbers: 1911625

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No