Human whole body cold adaptation.

Area of Science:

• Human physiology
• Evolutionary biology
• Environmental adaptation

Background:

• Distinguishing population studies from acclimation studies is crucial for understanding human cold adaptation.
• Indigenous populations exhibit distinct cold responses compared to others.

Purpose of the Study:

• To clarify the differences between population-level cold adaptation and individual acclimation.
• To investigate physiological and behavioral adaptations to cold environments.

Main Methods:

• Comparative analysis of population studies (indigenous Africans, Caucasians, Inuit) and dedicated acclimation studies.
• Review of physiological responses to various cold exposures (whole body, cold water immersion).

Main Results:

• Indigenous Africans show reduced shivering thermogenesis and impaired cold-induced vasodilation compared to Caucasians and Inuit.
• Repeated severe cold exposure in individuals leads to reduced cold sensation but few physiological changes.
• Cold water immersion slightly decreases metabolic heat production; milder cold exposure may increase it, particularly non-shivering thermogenesis.

Conclusions:

• Significant human cold adaptation, involving increased metabolism and insulation, has occurred through recent population evolution.
• Lifetime acclimation to cold does not induce major physiological changes comparable to evolutionary adaptations.
• Behavioral strategies remain the primary means for human survival in cold climates.