The purpose of this study is to determine the effect of 5 days post-exercise hot water immersion on exercise performance at simulated altitude.
Human performance is compromised at altitude due to a lower partial pressure of oxygen and subsequent reductions in the convective transport of oxygen to tissue. Long-term acclimation to attitude incurs physiological adaptations that result in a near return to sea-level performance; however, the time required (\~2 weeks) for such adaptations is often logistically challenging for athletes, military personnel or other individuals who reside at sea level. Recent research suggests that physiological acclimation to heat stress (i.e., heat acclimation) and altitude (i.e., hypoxia) share similar cellular adaptations, namely an up-regulation of Hypoxia-inducible factor 1 (HIF-1) and various heat shock proteins. Therefore, it is hypothesized that heat acclimation may provide physiological protection from reduced oxygen transport to the tissue and enhance performance at altitude. This cross-tolerance model is supported by traditional heat acclimation protocols (i.e., submaximal exercise in hot ambient temperature); however, it has not been tested with passive exposure to heat stress through post-exercise hot water immersion.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
20
Participants will cycle for 60 minutes at 50% of maximal oxygen uptake (VO2 max) followed by 30 minutes post-exercise hot water immersion (40oC) for 5 consecutive days.
Participants will cycle for 60 minutes at 50% maximal oxygen uptake (VO2 max) for 5 consecutive days. There is no water immersion following the exercise.
Nipissing University
North Bay, Ontario, Canada
Time-Trial Performance in hypoxia conditions
Results of a 16 km time-trial test conducted at an fraction of inspired oxygen (FiO2) of 0.14
Time frame: 30 minutes
Pulse oxygen saturation during exercise
Capillary oxygen saturation measured on the earlobe throughout the time-trial tests using pulse oximetry.
Time frame: 30 minutes
Skin temperature during exercise
Skin temperature measured throughout the time trial-tests and exercise training intervention using temperature probes attached to the calf, thigh, chest and arm, from which weighted averages are calculated.
Time frame: 90 minutes
Core temperature during exercise
Core body temperature measured throughout the time-trial tests and exercise training interventions using a rectal temperature probe.
Time frame: 90 minutes
Heart Rate during exercise
Heart rate will be measured throughout the time trial tests and exercise training interventions using a wireless (Polar) heart rate chest strap.
Time frame: 90 minutes
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