Cold-induced vasodilation during sequential immersions of the hand

Area of Science:

• Physiology
• Environmental Medicine
• Human Performance

Background:

• Repetitive glove use in cold environments leads to cycles of hand cooling and rewarming.
• Understanding the physiological impact of repeated cold exposure on hand thermoregulation is essential for occupational safety and performance.

Purpose of the Study:

• To investigate the influence of repeated intraday hand cooling on cold-induced vasodilation (CIVD).
• To assess the effects of repeated cold exposure on sympathetic activation and finger/hand temperature recovery.
• To determine if sequential cold exposures impair physiological responses to cold.

Main Methods:

• Ten participants (8 males, 2 females) underwent two 30-minute hand immersions in cold water (4.3°C) with a 10-minute recovery period between immersions.
• Cold-induced vasodilation (CIVD) components, including onset time and minimum/mean finger temperatures, were measured for each finger (index, middle, ring).
• Finger and hand temperatures were monitored throughout the immersion and recovery phases to evaluate recovery rates.

Main Results:

• No significant differences were observed in CIVD onset time, minimum finger temperature, or mean finger temperature between the first and second cold immersions.
• Finger temperature recovery rates showed similar patterns between the two sequential immersions.
• Sympathetic activation levels were not explicitly detailed but the overall CIVD response remained consistent.

Conclusions:

• Repeated hand cooling within the same day does not negatively affect cold-induced vasodilation (CIVD) responses or subsequent temperature recovery.
• These findings suggest that the physiological capacity to respond to cold stimuli remains intact despite prior exposure.
• The results are promising for individuals who frequently expose their hands to cold conditions, indicating resilience in thermoregulatory function.