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The increased oxygen uptake upon immersion. The raised external pressure could be a causative factor
1School of Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada.
Summary
Cold water immersion initially increases ventilation and oxygen uptake due to both cold receptor stimulation and hydrostatic pressure effects. This hydrostatic component shifts blood, temporarily boosting oxygen uptake.
Area of Science:
- Physiology
- Environmental Medicine
Background:
- Cold water immersion typically elevates immediate transient ventilation (VE) and oxygen uptake (VO2).
- Cutaneous cold receptor stimulation is the traditionally accepted primary driver of these responses.
Purpose of the Study:
- To investigate the components contributing to the initial VE and VO2 responses during cold water immersion.
- To differentiate between thermogenic and hydrostatic influences on physiological responses.
Main Methods:
- Human subjects were immersed in water at various temperatures (10, 15, 20, 28, 40 degrees C).
- Peak VE and VO2 were measured during the first minute of immersion.
- Analysis focused on identifying contributions beyond simple cold receptor stimulation.
Main Results:
- Peak VE values ranged from 66.8 L.min-1 (10°C) to 19.5 L.min-1 (40°C).
- Peak VO2 values ranged from 1.22 L.O2.min-1 (10°C) to 0.78 L.O2.min-1 (40°C).
- Responses showed significant variation across different water temperatures.
Conclusions:
- Initial increases in VE and VO2 during cold water immersion have both thermogenic and hydrostatic components.
- Hydrostatic pressure contributes to increased VO2 by shifting venous blood and enhancing oxygen uptake.