Aging and human cold tolerance

Area of Science:

• Gerontology
• Environmental Physiology
• Thermoregulation

Background:

• Hypothermia poses a greater risk to older adults due to potentially impaired thermoregulatory defenses.
• Epidemiological data suggest increased hypothermia-related mortality with age, but home body temperatures in older individuals are often normal.
• Laboratory studies provide more reliable data on thermoregulatory responses to cold stress in different age groups.

Purpose of the Study:

• To compare the thermoregulatory responses to cold exposure in younger and older individuals.
• To investigate potential age-related differences in the ability to defend core body temperature during cold stress.
• To identify factors contributing to impaired thermoregulation in older populations.

Main Methods:

• Controlled laboratory experiments exposing younger and older subjects to cold stress.
• Measurement of core body temperature and assessment of metabolic heat production.
• Evaluation of cutaneous vasoconstrictor responses to cold stimuli.

Main Results:

• Older men generally showed a reduced ability to defend core temperature compared to younger men.
• Older men exhibited a smaller increase in metabolic heat production and a less responsive vasoconstrictor response to cold.
• Older women demonstrated comparable or superior core temperature defense during cold exposure relative to younger women.

Conclusions:

• Impaired thermoregulation in older adults during cold exposure may be more pronounced in men.
• Factors such as changes in body composition and physical fitness, rather than aging itself, might underlie observed thermoregulatory deficits.
• Further research should focus on modifiable factors to improve cold resilience in older populations, particularly older workers.