Utility of Transdermal Optical Imaging (TOI) as a Non-invasive Measure of Hydration Status: Phase 3a for Model Development

The primary objective of this study is to analyze smart phone-based Transdermal Optical Imaging (TOI) features to develop a model that can discern hypohydration from euhydration status including 1) a small feasibility study for 24-hour data collection in the general population using passive dehydration or ad libitum fluid intake (GENPOP), 2) an exercise study in moderately active participants in both dehydrated and euhydrated states (EXERCISE). TOI data will be collected alongside standard reference measures of hydration status. This is an exploratory pilot proof of concept study with each subject serving as their own control.