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 Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
17
Consumption of a water volume (from water) equal to 150% of body mass loses from exercise-induced hypohydration
Consumption of a water volume (from a glucose-based sports drink) equal to 150% of body mass loses from exercise-induced hypohydration
Consumption of a water volume (from a fruit beverage) equal to 150% of body mass loses from exercise-induced hypohydration
Nottingham Trent University, Clifton Campus
Nottingham, United Kingdom
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)
Time frame: Baseline (pre-exercise), post-exercise, and 0, 1, 2, 3, and 4 h post-rehydration
Cumulative urine volume
Time frame: 0, 1, 2, 3, and 4 h post-rehydration
Total urine volume
Total urine volume produced during the rehydration period
Time frame: 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
Time frame: 4 h post-rehydration
Blood glucose concentration
Time frame: 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
Time frame: The 2h period following rehydration
Hyperglycaemia incidence
Number of participants that experience blood glucose \> 7.8 mmol/L
Time frame: The 2 h period following rehydration
Hypoglycaemia incidence
The number of participants that experience blood glucose \< 3.9 mmol/L
Time frame: The 2 h period following rehydration
Urine osmolality
A measure of urine concentration.
Time frame: 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.
Time frame: 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)
Time frame: 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)
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
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