The investigators want to understand the impact of the body losing and gaining water on brain function. Participants will restrict fluids consumed and exercise to lose 5% of body mass. Participants will then be provided fluid equal to the volume lost to consume over 2 hours (recovery). A series of brain function tests will be performed at baseline, following weight loss, and following recovery.

A baseline series of brain function tests will be performed. Following this, participants will complete a 24 hour fluid and water rich food restriction on the day proceeding testing. Participants will then complete moderate to high intensity exercise in a hot/humid room to achieve 5% body mass loss. Once baseline core body temperature returns to baseline levels, the series of brain function tests will be performed. Participants will then consume a sports drink equal to the volume of sweat lost over the course of a 2 hour recover period. Following this, he series of brain function tests will be performed.

Inclusion Criteria:

• Healthy
• Recreationally active
• 18-26 years old

Exclusion Criteria:

• History of cardiovascular, metabolic, respiratory, neural, or renal disease
• Hypertensive (systolic blood pressure ≥ 140 mmHg, diastolic blood pressure ≥ 90 mmHg) or tachycardic (resting heart rate ≥ 100 bpm) during the screening visit
• Taking medication or supplements with a known side effect of affecting physiological responses to exercise (e.g., aspirin, acetaminophen, beta blockers, statins, stimulants, depressants, SSRIs)
• Tobacco or nicotine use in the past six months
• Current or past musculoskeletal injury impacting physical activity
• Study physician discretion based on any other medical condition or medication

Coded data or the methodology will be shared with researchers upon reasonable written request.

Data can be shared for as long as the data is retained, at least 7 years.

Data will be shared upon reasonable written request.