Real-time microwearable sensor for monitoring human hydration status

INTERVENTION: Fluid restriction followed by exercise‐induced dehydration The first visit (less than one hour) will involve several measures of hydration status (including body weight, a small quantity of blood collected via venipuncture in the arm and urine samples). You will then go about your normal daily activities for the next 24 hours but will be requested to minimise fluid intake. The following dietitian guided information will be provided: In the 24 hours leading up to your exercise session, please minimise: ‐ drinks & liquids e.g. water, coffee, tea, soft drink, sports drinks, milk, juice, alcohol ‐ fluids that are part of a food e.g. soup, sauces, gravies, pudding, yoghurt, salad dressing ‐ foods that will melt down to a liquid e.g. ice cream, frozen yoghurt, milkshakes/smoothies, ice blocks, ice cubes ‐ juicy fruits or vegetables e.g. melons (watermelon, rockmelon,honeydew, etc.), berries (strawberries, blueberries, raspberries, blackberries, etc.), tomatoes, cucumbers To reduce thirst and alleviate dry mouth: ‐ eat a low salt diet (salty foods will increase your thirst) ‐ keep hard candies, mints and gum available. some people find sugar‐freevarieties to be more thirst quenching ‐ brush your teeth ‐ chill mouthwash and gargle for a fresh feeling ‐ rinse your mouth with water (no swallowing). ‐ add lemon or cucumber to your water to help quench your thirst. ‐ freeze or partially freeze pieces of fruit for a refreshing treat: like lemon wedges, orange sections, peaches, berries, or grapes ‐ breathe through your nose and not your mouth ‐ avoid mid‐day heat The second and final visit (24 hours following the first) will involve exposure to a hot and dry environment (40 deg C and 20% relative humidity). You wi CONDITION: Dehydration; ; Dehydration Diet and Nutrition ‐ Other diet and nutrition disorders PRIMARY OUTCOME: Diagnostic performance of Microwearable for detection of the dehydrated state.; ; Diagnostic performance will be determined by receiver operating characteristic (ROC) analysis of a binary classification distinguishing euhydrated and dehydrated states, in the validation group.; The area under the curve (AUC) and its 95% confidence interval will be calculated to determine the predictive performance of the Microwearable. A participant’s hydration status will be defined using a 2% body mass loss and 295 mOsm/kg serum osmolality (determined by blood test) cut off, as well documented in the literature, with values <2% and 295 mOsm/kg considered hydrated, and values >2% and 295 mOsm/kg considered dehydrated. True positive and negatives, as well as false positive and negatives will be identified.; [Post 150 minutes of exercise of both exercise sessions] INCLUSION CRITERIA: To be eligible for study entry participants must satisfy all of the following criteria: 1. Male or female over 18 years of age, inclusive at the time of screening; 2. Generally healthy and considered to be of ‘Low Risk’ for suffering from an adverse event during physical activity per the Exercise and Sports Science Australia (ESSA) adult pre‐exercise screening tool; 3. Partake on average in greater than or equal to 150‐minutes weighted physical activity per week; with an emphasis on endurance exercise; 4. Able to provide voluntary, written informed consent with comprehension of all aspects of the protocol, prior to any study procedures. SECONDARY OUTCOME: Diagnostic performance of Microwearable for detection of the dehydrated state. ; ; Diagnostic performance will be determined by receiver operating characteristic (ROC) analysis of a binary classification distinguishing euhydrated and dehydrated states, in the validation group. ; The area under the curve (AUC) and its 95% confidence interval will be calculated to determine the predictive performance of the Microwearable. A participant’s hydration status will be defined using a 2% body mass loss and 295 mOsm/kg serum osmolality (determined by blood test) cut off, as well documented in the literature, with values <2% and 295 mOsm/kg considered hydrated, and values >2% and 295 mOsm/kg considered dehydrated. True positive and negatives, as well as false positive and negatives will be identified.[Pre‐exercise and following 30, 60, 90 and 120 minutes of exercise for both exercise sessions]