What is the Origin of Thermal Acclimation?

The term combines "thermal," relating to heat, with "acclimation," derived from the Latin acclimare (to habituate to a climate), signifying a long-term, systemic, and adaptive change in physiological function. This concept is foundational to environmental physiology and the study of human adaptation to climate.

What is the Mechanism of Thermal Acclimation?

Chronic exposure to cold, for instance, drives the sustained up-regulation of uncoupling proteins in brown adipose tissue, significantly increasing non-shivering thermogenesis and overall metabolic rate, often mediated by sustained sympathetic nervous system activity and thyroid hormone. Conversely, heat acclimation enhances plasma volume, reduces cardiovascular strain, and increases sweating efficiency. Both processes involve a sustained shift in neuroendocrine control to maintain core body temperature with less overall physiological strain.

Thermal Acclimation ∞ Area

Thermal Acclimation

Meaning

Thermal Acclimation is the long-term physiological and adaptive process by which an organism gradually adjusts its core biological functions, including metabolic rate, hormonal response, and cardiovascular dynamics, in response to chronic, non-lethal exposure to a specific environmental temperature, whether hot or cold. This is a slow, multi-week process that fundamentally alters the body’s homeostatic set points to enhance survival and sustained performance in the new thermal environment. It is distinct from the body’s immediate, acute thermoregulatory response.