Cold Exposure

    Written by:
    Bill Willis
    Fact-checked by:
    Katie Jantz, Conni Covington
    Last Updated: March 25, 2025

    Cold exposure is the practice of voluntarily exposing the body to temperatures that are colder than comfortable, triggers an adaptive stress response. This response is currently a topic of research for benefits on the mind and body.



    1.

    What is cold exposure

    Cold exposure is a manipulation of thermoregulation in the extreme of reducing temperature, by changing the external temperature Cold Exposure attempts to achieve certain cellular effects which can be used towards ones goals.

    Thermoregulation techniques are built around the concept of adaptive thermogenesis. The human (adult) body maintains a temperature of 98.2 +/- 0.6 °F, which translates into 36.4–37.1 °C.[1] Changes below this threshold will cause adaptive changes to maintain said range[2] and changes above this threshold will cause changes to counter the change in the opposite. As per the 'adaptive' of adaptive thermogenesis, changes are not acute and cold exposure will need to be done routinely.[3]

    In regards to cold metabolism, two types of reactions occur. Insulative actions which involve redirection of blood flow away from extremities, and metabolic changes that result in an increase of the metabolic rate to produce extra heat via uncoupling reactions.[2] The former is seen as a consequence of the cold (cold fingers) while the latter is what Cold Exposure aims to manipulate.

    If one method of temperature regulation is limited, the other must compensate. Thus by limiting insulative reactions, one can increase metabolic reactions.[4][5]

    2.

    Insulative actions

    Insulative actions are the first line of defense in thermoregulation and are metabolically cheap.[3] These include warmth-seeking behaviour, piloerection (goose bumps), vasoconstriction to decrease subcutaneous blood flow, and changing body positions to decrease surface area.[6] Although beneficial to survival and metabolically convenient, they are opposite of the most common goals of cold exposure therapy (fat mass loss, increased metabolic rate) due to their metabolic efficiency.

    After insulative reactions have been exhausted, then non-shivering adaptive thermogenesis (NST) is recruited.

    3.

    NST - Muscle response to cold exposure

    Skeletal muscle appears to be a reserve for Non-shivering adaptive thermogensesis in man. In particular the reserve of potential heat comes from upregulation of Myosin ATPase activity from conversion of a 'Super-relaxed' (highly inhibited) state of myosin into an 'active' state of myosin.[7][8] The accompanying increase in ATPase activity comes with an increase in substrate utilization and mitochondrial uncoupling[9], more subsequently more heat production.[8]

    The significance of this reactions is summed up with the quote from Cooke.[8] That "Shifting only 20% of myosin heads from the (Super relaxed state) into the relaxed state would increase muscle thermogenesis by approximately a factor of two, increasing whole body metabolic rate by about 16%". Information gathered initially from in vitro studies on myosin cultures and later supported with in vivo research.

    4.

    NST - Body fat response to cold exposure

    Brown body fat is another reserve for non-shivering adaptive thermogenesis in adult man, although it (brown fat) is much more active in youth.[10]

    Brown fat's role in heat production comes from a protein called 'Thermogenin', or Uncoupling Protein 1 (UCP1). Two other UCPs exist (2 and 3, respectively).[11] UCP1 works by disturbing the mitochondrial proton gradient used in ATP production by shuttling protons back across the inner mitochondrial membrance independent of ATP Synthase.[12][13][14]

    After muscle and fat contribute to Non-shivering Thermogenesis (NST), then shivering thermogenesis is recruited.

    5.

    Shivering thermogenesis

    Shivering is defined as rapid oscillations of the body to produce kinetic heat.[6]

    Low-grade shivering is a physical exertion which primarily uses fatty acids as substrate. However, at higher intensities a gradual shift to carbohydrate as the primary fuel substrate is used.[15] Glycogen is primarily used rather than serum glucose.[16]

    6.

    Other interactions with Cold Exposure and Metabolic Rate

    Cold exposure seems to induce a greater recompensatory thermic effect of food (TEF) upon introduciton of food, and is more significant in periods of moderate eating rather than overfeeding.[4] This may be because of similar cellular mechanics between overfeeding and cold exposure, as both possess similar inter-individual differences[17] although UCP1 does not seem to be suspect.[18]

    These relations may exemplify why some animal reports have found clinically significant weight loss in drastically overfed animals exposed to near zero temperatures for a prolonged period of time.[19][20] Although these drastic results may not be applicable to humans due to a lack of B3-beta adrenergic receptor proliferance on our white adipose tissue.[21]

    7.

    Significance

    Studies vary depending on the degree of cold and an individual's tendency to compensate with either insulative or metabolic changes. Some results report:

    • An additional 4-6% energy expenditure when the temperature is dropped 6°C relative to comfort level. [4][22]

    References

    1. ^Normal oral, rectal, tympanic and axillary body temperature in adult men and women: a systematic literature review
    2. ^van Marken Lichtenbelt WD, Daanen HACold-induced metabolismCurr Opin Clin Nutr Metab Care.(2003 Jul)
    3. ^Cannon B, Nedergaard JNonshivering thermogenesis and its adequate measurement in metabolic studiesJ Exp Biol.(2011 Jan 15)
    4. ^van Marken Lichtenbelt WD, Schrauwen P, van De Kerckhove S, Westerterp-Plantenga MSIndividual variation in body temperature and energy expenditure in response to mild coldAm J Physiol Endocrinol Metab.(2002 May)
    5. ^Wijers SL, Saris WH, van Marken Lichtenbelt WDCold-induced adaptive thermogenesis in lean and obeseObesity (Silver Spring).(2010 Jun)
    6. ^Makinen TMDifferent types of cold adaptation in humansFront Biosci (Schol Ed).(2010 Jun 1)
    7. ^Stewart MA, Franks-Skiba K, Chen S, Cooke RMyosin ATP turnover rate is a mechanism involved in thermogenesis in resting skeletal muscle fibersProc Natl Acad Sci U S A.(2010 Jan 5)
    8. ^Cooke RThe role of the myosin ATPase activity in adaptive thermogenesis by skeletal muscleBiophys Rev.(2011 Mar)
    9. ^Wijers SL, Schrauwen P, Saris WH, van Marken Lichtenbelt WDHuman skeletal muscle mitochondrial uncoupling is associated with cold induced adaptive thermogenesisPLoS One.(2008 Mar 12)
    10. ^Cypess AM, Kahn CRThe role and importance of brown adipose tissue in energy homeostasisCurr Opin Pediatr.(2010 Aug)
    11. ^Enerbäck SBrown adipose tissue in humansInt J Obes (Lond).(2010 Oct)
    12. ^Palou A, Picó C, Bonet ML, Oliver PThe uncoupling protein, thermogeninInt J Biochem Cell Biol.(1998 Jan)
    13. ^Jia JJ, Tian YB, Cao ZH, Tao LL, Zhang X, Gao SZ, Ge CR, Lin QY, Jois MThe polymorphisms of UCP1 genes associated with fat metabolism, obesity and diabetesMol Biol Rep.(2010 Mar)
    14. ^Jia JJ, Zhang X, Ge CR, Jois MThe polymorphisms of UCP2 and UCP3 genes associated with fat metabolism, obesity and diabetesObes Rev.(2009 Sep)
    15. ^Haman F, Blondin DP, Imbeault MA, Maneshi AMetabolic requirements of shivering humansFront Biosci (Schol Ed).(2010 Jun 1)
    16. ^Weber JM, Haman FFuel selection in shivering humansActa Physiol Scand.(2005 Aug)
    17. ^Wijers SL, Saris WH, van Marken Lichtenbelt WDIndividual thermogenic responses to mild cold and overfeeding are closely relatedJ Clin Endocrinol Metab.(2007 Nov)
    18. ^Anunciado-Koza R, Ukropec J, Koza RA, Kozak LPInactivation of UCP1 and the glycerol phosphate cycle synergistically increases energy expenditure to resist diet-induced obesityJ Biol Chem.(2008 Oct 10)
    19. ^Nikonova L, Koza RA, Mendoza T, Chao PM, Curley JP, Kozak LPMesoderm-specific transcript is associated with fat mass expansion in response to a positive energy balanceFASEB J.(2008 Nov)
    20. ^Guerra C, Koza RA, Yamashita H, Walsh K, Kozak LPEmergence of brown adipocytes in white fat in mice is under genetic control. Effects on body weight and adiposityJ Clin Invest.(1998 Jul 15)
    21. ^Kozak LPBrown fat and the myth of diet-induced thermogenesisCell Metab.(2010 Apr 7)
    22. ^Dauncey MJInfluence of mild cold on 24 h energy expenditure, resting metabolism and diet-induced thermogenesisBr J Nutr.(1981 Mar)