An interventional study of Exercise in Hydration Status, sponsored by PepsiCo Global R&D. Recruiting at 2 sites in United States. Open to participants aged 18 Years to 45 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-09-21.
Sponsored by PepsiCo Global R&D · Not applicable, Interventional, and Other
Hydration status during exercise is often determined by measuring body mass change, fluid intake and urine output. However, obtaining these measurements can be an invasive, time-consuming process. Hydration status may be detectable by analyzing blood flow patterns of the superficial (just under the skin) blood vessels. Wearable devices are now abundant among the general population, and despite attempts from several groups, a hydration status metric based on noninvasive wearable device metrics has not been developed. With wearables, a light source connected to an optical sensor transmits and reflects light through the body. The light sensor detects absorption of the light based on wavelength measurements of the detected light. Absorption of specific wavelengths of light energy is dependent upon the amount of oxygenated blood in the vessels. When the vessels expand and relax, the amount of blood volume in the observed tissue increases and decreases potentially causing a shift in the photoplethysmography (PPG) wave detected by the wearable. The shift in the shape of the PPG wave may be detected in a way that indicates the relative change in tissue hydration levels. However, to our knowledge, no wrist worn device that utilizes PPG has been successfully able to predict hydration status. Therefore, this study aims to utilize photoplethysmography (PPG) technology in a wearable device to accomplish this approach to hydration monitoring.
Exclusion Criteria:
Water provided to account for sweat loss during exercise and to maintain hydration over the 24-hour period
Other: Exercise
Fluid restriction during exercise and the remaining 24 hours
Other: Exercise
Perform stationary cycling exercise in the laboratory for 2 30- minute bouts at a standardized exercise intensity (wattage) that elicits 50-80% heart rate max determined by equation (208-(70% of age))
Wearable Sensr Data
photoplethysmogram (PPG) waveform data- optical signals obtained from photoplethysmography, which measure blood volume changes in the microvascular bed of tissue.
Time frame: Continuous data collection over 24 hours from start of exercise trial through completion of Day 2 measurements.
Body Mass Change
Time frame: Change in body mass during 60 min exercise bout and over 24 hours from baseline
Urine Specific Gravity
au
Time frame: Day 1: Baseline, post 1st and 2nd 30 min exercise sessions Day 2: 1st morning void collected at home and upon arrival at laboratory
Urine Volume
g
Time frame: Day 1: Baseline, post 1st and 2nd 30 min exercise sessions Day 2: 1st morning void collected at home and upon arrival at laboratory
Urine Color
Scale of 1 (most hydrated) to 7 (most dehydrated)
Time frame: Day 1: Baseline, post 1st and 2nd 30 min exercise sessions Day 2: 1st morning void collected at home and upon arrival at laboratory
Sweat Rate
\[Body mass loss (kg) + fluid intake (mL)\]/Duration of exercise (hr)
Time frame: Throughout entire duration of 60 min exercise bout
Fluid Intake
mL
Time frame: documented by subject on provided log for 24 hours prior to exercise and experimental trials. Exercise bouts- DEH group restricted from fluid intake. EUH group fluid measured over duration of exercise bout (60 minutes).
Subjective Feelings of Thirst
Categorical Thirst Scale, on a scale of 1 (Not thirsty at all) to 7 (very, very thirsty).
Time frame: Day 1 & 2: Following 5 min of rest
Heart Rate
bpm
Time frame: At medical screening to determine eligibility. Day 1: Prior to start of exercise bouts during 5 min rest and every 10 min throughout entire duration of each 60 min exercise trial. Day 2: During 5 min rest, prior to body weight measurement.
Blood pressure
systolic/diastolic (mmHg)
Time frame: Medical Screening to determine eligibility
Subject Demographics
Age, Sex, Race, and Ethnicity
Time frame: At baseline
Dietary Intake
Food intake logs
Time frame: Completed for 24 hours prior to baseline and between visits.
Standardized Exercise Intensity
W
Time frame: Every 10 min throughout entire duration of each 30 min exercise bout to reach 50-80% of heart rate max.
Rate of Perceived Exertion
Borg Scale, a scale of 6 (No exertion at all) to 20 (maximal exertion)
Time frame: Every 10 min throughout entire duration of each 30 min exercise bout
Plan to share: No
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PepsiCo Global R&D