The purpose of the study is to compare physiological responses to two hours of work adhering to two variations of a work-to-rest ratio in a hot environment.

Inclusion Criteria:

• Healthy 18-39 year old individuals
• Physically active

Exclusion Criteria:

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

We do not plan to share these data with other researchers.