Transdermal Optical Imaging (TOI) as a Non-invasive Measure to Detect Changes in Hydration Status in Healthy Adults and Athletes

Inclusion Criteria: Both Study Arms (GENPOP and ATHLETE) * Subject is male or female * If female, subject is not pregnant * Subject is willing to avoid alcohol consumption 24 hours prior to visit(s) * Subject is willing to avoid wearing makeup to the study session or willing to remove it with facial wipes before the face scans * 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 GENPOP Study * Study subject is 18-65 years of age, inclusive * 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 fast overnight (\~8-12 hours) * Subject is willing to refrain from vigorous exercise for 48 hours * Subject is willing to eat the exact same food the day prior to each visit to the testing site ATHLETE Study * Study subject is 14-45 years of age, inclusive * Subject is participating in team sport training/competition * Subject is participating in a coach-led practice Exclusion Criteria: Both Study Arms (GENPOP and ATHLETE) * Subject has participated or currently enrolled 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 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. GENPOP Study • Subject has a health condition or is taking medication that can be worsened by fluid restriction (participants who opt-in to fluid restriction study arm only)