Buoy Electrolyte Study on Hydration Status of Active Men and Women

Prior to initiation of the study, participants will have a screening visit to complete informed consent and health history. The history for females will include their last date for menstruation and/or birth control method to take into consideration the effects of ovulation on water retention. During this visit we will measure heart rate, blood pressure, height, weight. Females will be administered a urine pregnancy test.

Participants must refrain from vigorous exercise within 24 hours of study visit. Participants will fast (food) overnight for 10h prior to initiation of test. Upon waking they are asked to empty their bowel & bladder. They can consume one 8oz cup of coffee or other liquid. They will present at 7-8am at which time they will be asked to empty their bladder again. After resting for 5 minutes baseline vitals will be taken, including blood pressure, heart rate, weight, bioimpedance. Urinalysis dipstick for protein/blood/glucose and i-STAT measurement for creatinine and electrolytes on Visit 1 to confirm eligibility. For Visit 2 and Visit 3, the participant will be asked to review medical history and any change in status may warrant an additional baseline creatinine and blood/protein test to confirm eligibility. Additional food or beverage will not be allowed throughout the study period. All studies will be repeated in the same subject using either Buoy (intervention) or water (control) or Nuun (intervention). Urine will be collected at four specific timepoints during the intervention and the volume will be recorded. If participants need to urinate between scheduled collection times, urine will be collected, volume recorded, and combined with the urine collection of the following timepoint. These urine samples will be measured and a fraction of it will be sent to the lab to be tested for the following electrolytes: sodium, potassium, chloride and urine osmolarity. Urine creatinine will also be tested at these timepoints.

Inclusion criteria

• Male or female, >18 to 45 years of age
• Freely given written consent
• Non-tobacco users
• Negative pregnancy test in women of childbearing potential
• BMI < 35 kg/m2
• GFR > 60 ml/min
• No known underlying medical condition
• Willing to refrain from EtOH for 24h prior to test day
• Willing to refrain from strenuous exercise for 24 h prior to each test day
• Acceptable to have one 8oz cup of coffee/liquid on the morning of the test, but must be consistent each visit
• Without active infection of any kind
• Engaged in exercise three or more hours per week

Exclusion criteria

• Abnormal creatinine (Cr > 1.2).
• Proteinuria / hematuria / glucosuria based on urine dipstick.
• Diagnosed medical condition that would impede results (CHF, HTN, CAD, CKD, history of electrolyte abnormality).
• Pregnancy
• Use of diuretics within past 2 weeks
• Obesity (BMI > 35)
• Active infection based on symptoms (bacterial or viral)
• Hemodynamic abnormality at screening visit: Blood pressure less than 100/60 or greater than 140/90.