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.

Inclusion Criteria:

• Subject is male or female
• If female, subject is not pregnant
• For GENPOP study subject is 18-65 years of age, inclusive
• For EXERCISE study subject is 18-50 years of age, inclusive
• Subject is moderately-trained (engages in moderate-intensity, intermittent, or steady-state exercise at least 3 days per week for at least 1 hour at a time (EXERCISE session participants only)
• Subject does not smoke (or has quit for at least 6 months)
• Subject is not taking medication that may interfere with the study
• Subject has no health conditions that would prevent completion of the trial as indicated on the general health questionnaire (GHQ)
• Subject is willing to avoid alcohol consumption 24 hours prior to visit(s)
• Subject is willing to fast overnight (~8-12 hours)
• For GENPOP, subject is willing to refrain from vigorous exercise for 48 hours
• For EXERCISE, subject is willing to refrain from vigorous exercise for 24 hours prior to study visits
• Subject is willing to eat the exact same food the day prior to each visit to the laboratory
• Subject is willing to avoid wearing makeup to the study session
• Subject is willing to shave facial hair if predetermined during the informed consent session it will interfere with TOI measurement
• Able to speak, write, and read English
• Provision of written consent to participate

Exclusion Criteria:

• Subject has participated in a clinical trial within the past 30 days
• Subject has participated in any PepsiCo trial within past 6 months
• Subject has a condition or is taking medication that the investigator believes would interfere with his/her ability to provide informed consent, comply with the study protocol, which might confound the interpretation of the study results, or put the person at undue risk
• Subject is allergic to alcohol or facial cleansing wipes
• Subject has a history of anaphylaxis or severe allergic reactions
• Subjects has a health condition or is taking medication that can be worsened by fluid restriction
• Subject has asthma or other condition which breathing can become labored during exercise (EXERCISE session participants only)
• Male subjects with a VO2max < 42 ml/kg/min and females with a VO2max < 38 ml/kg/min (EXERCISE session participants only)
• Subject is employed by, or has a parent, guardian, or other immediate family member employed by a company that manufactures any products that compete with any Gatorade product. If subject is unsure if a company would be considered a competitor to Gatorade, they will be asked to please let the study investigator know the name of the other company and the nature of their relationship to that company before they sign the informed consent.