Physiological Responses to Cold Exposure

Exposure to cold elicits a coordinated array of physiological mechanisms aimed at preserving core temperature and maintaining homeostasis. Initial responses involve peripheral vasoconstriction to minimise heat loss, accompanied by behavioural adjustments such as seeking shelter or adding layers. If core temperature falls, shivering thermogenesis ensues, driven by involuntary skeletal muscle contractions that generate heat. Concurrently, non-shivering thermogenesis is activated in brown adipose tissue and, to a lesser extent, in skeletal muscle via mitochondrial uncoupling and enhanced substrate oxidation. Neuroendocrine pathways engage the sympathetic nervous system and release catecholamines, thyroid hormones and stress mediators, which together augment metabolic rate and modulate immune function. Prolonged or repeated cold exposure induces acclimation, shifting the balance between insulative adaptations—such as increased peripheral vasoconstriction and altered skin blood flow—and metabolic adaptations, including upregulation of thermogenic pathways. These responses not only have implications for survival in extreme environments but also inform clinical strategies for metabolic disorders, athletic recovery and occupational safety in cold settings.

Research from Nature Portfolio

Recent studies have investigated the metabolic and cardiovascular consequences of mild cold acclimation in individuals with type 2 diabetes. A ten-day protocol at mildly cool temperatures, designed to prevent overt shivering, failed to enhance insulin sensitivity, postprandial glucose handling or intrahepatic lipid reduction. Only modest increases in overnight fat oxidation and postprandial energy expenditure were observed. Transcriptomic analysis of skeletal muscle revealed no upregulation of contraction-related gene networks, underscoring the necessity of muscle activity—even sub-shivering contractions—for full activation of thermogenic and metabolic benefits in humans.

Research from all publishers

Investigations in ageing rodent models have demonstrated that regular cold-water swimming enhances mitochondrial biogenesis and energy metabolism in skeletal muscle. Rats exposed to water at 5 °C over nine weeks exhibited increased levels of ATP and adenylate charge, upregulated expression of fusion regulatory proteins and markers of mitochondrial dynamics, suggesting an additive benefit of cold stress on muscle bioenergetics beyond that of exercise alone.

A systematic review of human studies on cognitive performance under cold stress revealed consistent impairments in attention, processing speed, executive function and memory across a variety of protocols. Most experiments reported decrements even before hypothermia onset, highlighting the sensitivity of cognitive domains to modest drops in ambient or core temperature and emphasising the need for countermeasures in occupational and emergency contexts.

Comprehensive analyses of human cold habituation have characterised a multi-phase timeline in which short-term, mild exposures first lead to reduced shivering and attenuated vasoconstriction—preserving peripheral temperature and conserving energy—followed by hypermetabolic and insulative adaptations after more severe or repeated stress. Modifiers of this response include exposure intensity, body composition and autonomic regulation, with implications for designing acclimation protocols in both civilian and military settings.

Physiological Responses to Cold Exposure publication trend

The graph below shows the total number of articles in physiological responses to cold exposure across all publications each year (not limited to Nature Index journals).

Technical terms

Adaptive thermogenesis: Increase in heat production via metabolic processes in response to cold or overfeeding.

Non-shivering thermogenesis: Heat generation by brown adipose tissue and mitochondrial uncoupling without muscle contractions.

Shivering thermogenesis: Involuntary rhythmic muscle contractions producing heat.

Vasoconstriction: Narrowing of blood vessels to reduce peripheral heat loss.

Cold acclimation: Physiological adjustments over days to weeks that improve tolerance to cold stress.

Brown adipose tissue (BAT): Fat depots specialised in heat production through high mitochondrial content and UCP1 activity.

References

1. Metabolic responses to mild cold acclimation in type 2 diabetes patients. Nature Communications (2021).
2. The Effect of Cold-Water Swimming on Energy Metabolism, Dynamics, and Mitochondrial Biogenesis in the Muscles of Aging Rats. International Journal of Molecular Sciences (2024).
3. The Effect of Cold Exposure on Cognitive Performance in Healthy Adults: A Systematic Review. International Journal of Environmental Research and Public Health (2021).
4. Human cold habituation: Physiology, timeline, and modifiers. Temperature (2021).