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Rapid changes in rate-corrected and uncorrected systolic time intervals during cold pressor test
Aviation, Space, and Environmental Medicine
|February 1, 1985
Summary
Cold water immersion affects heart rate and systolic time intervals. Changes observed in left ventricular ejection time and electromechanic systole varied based on body position during the brief cold stimulus.
Area of Science:
- Cardiology
- Human Physiology
- Environmental Medicine
Background:
- Systolic time intervals (STIs) reflect cardiac function.
- Cold exposure can elicit physiological responses, including cardiovascular changes.
Purpose of the Study:
- To investigate the effects of acute hand cold immersion on heart rate and STIs in healthy young males.
- To assess if body position influences these cardiovascular responses to cold.
Main Methods:
- 10 healthy young males underwent 1-minute hand immersion in ice water.
- Electrocardiograms, phonocardiograms, and impedance cardiograms were used to measure heart rate and STIs.
- Measurements were taken in both supine and head-up positions.
Main Results:
- In the supine position, left ventricular ejection time (LVET) and electromechanic systole (Q-S2Tc) shortened. Rate-corrected Q-S2Tc initially lengthened.
- In the head-up position, Q-S2T shortened initially, while rate-corrected STIs remained unchanged.
- Most STI changes resolved before the end of immersion.
Conclusions:
- Acute cold water immersion induces transient changes in cardiac timing, influenced by body position.
- Standard rate correction methods may not fully account for heart rate variability during cold exposure.