Humans 3 Oxygen Consumption Article 2 Male 2 adult 2 female 2 human 2 male 2 oxygen consumption 2 Accurate estimation 1 Administration, Oral 1 Antigens, CD 1 Antigens, Differentiation, T-Lymphocyte 1 Atmospheric pressure 1 Bicycling 1 COSMED K5 1 COVID-19 1 Caffeine 1 Central Nervous System Stimulants 1 Connecticut 1 Controlled environment 1 Cost benefit analysis 1 Cost estimating 1 Cross-Over Studies 1 Electrocardiography 1 Energy expenditure 1 Environmental sensor 1 Exercise 1 Exercise Test 1 Exercise Tolerance 1