Effects of Drink Composition on the Appearance of Ingested Water in Body Fluids

Study Overview
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Brief Summary
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To determine the effects of amino acids on the rate of water absorption and availability as a precursor fluid for sweat. Young and healthy (male or female) volunteers will take part in three experimental trials. In each trial, volunteers will be given one of two commercially available sports drinks or a commercially available sport drink with added amino acids in a double-blinded, randomised, crossover design. Each drink will be a single 550 mL bolus. All beverages will be labelled with deuterium (D2O). Trials will be compared for temporal accumulation of deuterium in plasma over the course of 60 minutes and in urine (60 min). Whole blood measurements of haemoglobin and haematocrit will also be made and plasma volume changes calculated. It is hypothesised that the amino acid trial will increase the rate of fluid absorption.

Official Title
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Effects of Drink Composition on the Appearance of Ingested Water in Body Fluids

Conditions
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Rate of Water Appearance/Delivery in the Blood, Water Balance

Intervention / Treatment
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* Other: Composition of Sports Drink


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Generally fit and healthy (determined by health screen questionnaire) Recreationally active (minimum 3 hours of physical activity per week including walking) Exclusion Criteria: Any cardiovascular, gastrointestinal, renal or acute/chronic health conditions that may influence the outcomes Smoking (including vaping) BMI of greater than 30 (combined with a body fat percentage greater than 20%) or BMI lower than 17.5

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Double-blind, randomised, crossover design
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Commercially Available Sports Drink A<br>A commercially available sports water, with small amounts of flavouring, sweetener and electrolytes | Other: Composition of Sports Drink<br>* The composition of sport drinks will be manipulated to determine the effect of drink composition on the appearance of ingested water in body fluid.<br>|
| Experimental: Commercially Available Sports Drink B<br>A commercially available sports water, with small amounts of flavouring, sweetener and electrolytes. | Other: Composition of Sports Drink<br>* The composition of sport drinks will be manipulated to determine the effect of drink composition on the appearance of ingested water in body fluid.<br>|
| Experimental: Commercially Available Sports Drink A with added Amino Acids<br>The same as sports drink A above (a commercially available sports water, with small amounts of flavouring, sweetener and electrolytes), but with the addition of a small amount of amino acids ( 0.7 g/100 ml). | Other: Composition of Sports Drink<br>* The composition of sport drinks will be manipulated to determine the effect of drink composition on the appearance of ingested water in body fluid.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time at which drink absorption rate was maximum (t1) | Determined from D2O values in venous blood samples collected before and after drink ingestion | 60 minutes | 
| Time at which drink absorption rate returned to 0 (t2) | Determined from D2O values in venous blood samples collected before and after drink ingestion | 60 minutes | 
| Time at which 50% of drink was absorbed (t1/2) | Determined from D2O values in venous blood samples collected before and after drink ingestion | 60 minutes | 
| Maximum absorption rate of drink | Determined from D2O values in venous blood samples collected before and after drink ingestion | 60 minutes | 
| Area under the curve for D2O | Determined from D2O values in venous blood samples collected before and after drink ingestion | 60 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Plasma volume | Determined from haemoglobin and haematocrit measures in venous blood samples collected before and after drink ingestion | 60 minutes | 
| Plasma osmolality | Determined from venous blood samples collected before and after drink ingestion | 60 minutes | 
| Plasma sodium concentration | Determined from venous blood samples collected before and after drink ingestion | 60 minutes | 
| Plasma potassium concentration | Determined from venous blood samples collected before and after drink ingestion | 60 minutes | 
| Plasma glucose concentration | Determined from venous blood samples collected before and after drink ingestion | 60 minutes | 
| Plasma lactate concentration | Determined from venous blood samples collected before and after drink ingestion | 60 minutes | 
| Plasma creatinine concentration | Determined from venous blood samples collected before and after drink ingestion | 60 minutes | 
| Plasma amino acid concentration | Determined from venous blood samples collected before and after drink ingestion | 60 minutes | 
| Urinary D2O concentration | Determined from urine samples collected before and after drink ingestion | 60 minutes | 
| Urinary specific gravity | Determined from urine samples collected before and after drink ingestion | 60 minutes |