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Cold Stress

Cold exposure featured article

Introduction

Cold exposure to promote good health is an ancient practice, now used to reduce muscle soreness and promote muscle recovery after physical activity. However, regular cold exposure may also improve glucose and lipid metabolism, decrease inflammation, enhance immune function, and improve cognitive performance. The beneficial effects of cold exposure may be due to hormesis, a favorable biological response to a mild stressor. Hormesis triggers protective mechanisms that protect against future, more harmful stressors.

Despite the presumed benefits of cold exposure, it poses some risks, especially in unsupervised or uncontrolled conditions. See our overview of cold exposure safety concerns at the end of this article.

This article provides an overview of cold exposure modalities and the physiological responses, health effects, and safety concerns associated with the practice.

Cold exposure modalities

Common cold exposure modalities include cold water...

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Dr. Andy Galpin: The Optimal Diet, Supplement, & Recovery Protocol for Peak Performance

Posted on April 22nd 2025 (about 2 months)

Dr. Andy Galpin & Dr. Rhonda Patrick discuss nutrition, supplement, and recovery strategies for improving exercise performance.

cold stress

Can You Use Cold Exposure Without Sacrificing Gains?

Posted on September 27th 2024 (9 months)

In this clip, Dr. Luc van Loon discusses cold water immersion's effects on muscle recovery and optimal timing to avoid blunting gains.

cold stress

"Nothing Spikes Dopamine Like 1 Minute of This" - Andrew Huberman

Posted on September 26th 2024 (9 months)

In this clip, Dr. Andrew Huberman describes how deliberate cold exposure enhances stress tolerance and how this impacts dopamine release.

Topic Pages

  • Cold exposure

    Cold exposure elicits cold stress by activating sympathetic thermogenic pathways, provoking vasoconstriction, shivering, and brown adipose heat production.

News & Publications

  • Cold-water immersion may offer stress relief and immune benefits, but its effects are highly time dependent. journals.plos.org
    Sleep Inflammation Immune System Mental Health Cold Stress

    Cold-water immersion has surged in popularity, with ice baths and cold showers touted as shortcuts to better health. Advocates claim it improves mood, sharpens focus, and speeds up recovery. A recent study found that while cold exposure temporarily increased inflammation, it reduced stress 12 hours later, improved sleep, and reduced sick days.

    Researchers conducted a systematic review and meta-analysis of 11 studies involving more than 3,100 healthy adults investigating the effects of cold-water exposure on mental and physical health markers, including mood, stress, immunity, inflammation, and sleep quality. Participants in the various studies took cold showers or ice baths at temperatures between 7°C (45°F) and 15°C (59°F) for at least 30 seconds.

    The analysis revealed that inflammation spiked immediately after immersion and stayed elevated for an hour. Interestingly, stress levels dropped 12 hours later but remained unchanged at other time points. Cold exposure did not immediately boost immune function, but a separate analysis linked cold showers to a 29% drop in sickness absence. Participants reported better sleep and overall well-being but no changes in mood.

    These findings suggest that cold-water immersion may offer short-term stress relief and potential immune benefits, with highly time-dependent effects. The effects of cold exposure may be due to hormesis—a compensatory defense response that conditions the body against future stressors. Learn more in Aliquot #97: Thermal Stress, Part II: Unveiling the Power of Cold Exposure on Health and Performance

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  • Regular cold showers boost immune responses, increasing levels of immunoglobulins and cytokines critical in protecting against infections. www.sciencedirect.com
    Inflammation Immune System Cold Stress

    Cold exposure has long been used in traditional medicine for its many health benefits. However, recent research demonstrates that cold affects the immune system. A new study found that regular cold showers can increase immune cells and antibodies that protect against infections.

    Researchers assigned 60 healthy adults to one of two groups, one taking cold showers (five to 10 minutes at 10° to 15°C, 50° to 59°F) and the other hot showers (40° to 42°C, 104° to 107.6°F) for 90 days. Showers were brief, lasting just five to 10 minutes. They took blood samples at baseline, 30, 60, and 90 days to measure various immune factors, including immunoglobulins, cytokines, and interferon-gamma levels.

    They found that those who took cold showers had considerably higher levels of immunoglobulins (IgG, IgA, and IgM) and cytokines (interleukin-2 and interleukin-4). In contrast, those who took hot showers experienced decreased IgM levels and no marked changes in cytokine levels.

    These findings suggest that regular cold showers boost the body’s immune responses. Cold showers offer a practical and accessible alternative to full cold-water immersion, requiring no specialized equipment beyond a regular shower, and can be taken conveniently at home. Their brief duration minimizes the risk of hypothermia, making them a safer cold exposure option. Learn about the many health benefits of cold exposure in our comprehensive overview article.

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  • Whole-body cryotherapy improves mood, reduces anxiety, and enhances sleep quality, with specific enhancement in slow-wave, restorative sleep seen in a recent study. www.sciencedirect.com
    Sleep Mental Health Cold Stress

    Cold exposure offers surprising health benefits, and emerging evidence suggests that whole-body cryotherapy enhances wellness and even improves sleep. A recent study found that five days of daily cryotherapy improved mood, reduced anxiety, and enhanced sleep quality in healthy young adults.

    The study involved 20 physically active young adults who underwent five consecutive days of cryotherapy sessions and five consecutive days of no cold exposure. The cryotherapy sessions lasted five minutes in a chamber cooled to -90°C (-130°F). Researchers used actimetry, brain activity recordings, and self-reported questionnaires to measure the participants' sleep patterns. They also assessed their mood, anxiety, and heart rate variability during the nights following each condition.

    Participants who underwent cryotherapy reported a 9% improvement in subjective sleep quality, with women benefiting the most. The cryotherapy sessions also increased slow-wave sleep, the most restorative sleep phase, by an average of seven minutes per night. No substantial changes were observed in heart rate variability or other sleep parameters.

    These findings from this small study suggest that repeated whole-body cryotherapy is a promising strategy for improving slow-wave sleep and psychological well-being, especially for women. Learn more about cold exposure in our comprehensive overview article.

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  • Warming muscles prior to high-intensity exercise boosts power and performance by 11%, suggests a small study on cyclists. link.springer.com
    Exercise Heat Stress Cold Stress Sauna

    Study link:

    Athletes often warm up before a big race, but does heating your muscles make a difference? An early study found that warming muscles boosts performance by 11% during intense exercise—but at a cost.

    Researchers asked four young, healthy adults to perform 20-second high-intensity sprints on an exercise bike under four different muscle temperature conditions: room temperature, after leg immersion in hot water (44°C/111.2°F), and after immersion in cool water (18°C/64.4°F and 12°C/53.6°F). They measured the participants' muscle temperature and analyzed their peak force and power output during each sprint.

    They found that increasing muscle temperature using warm water immersion boosted peak force and power 11% more than resting at room temperature. In contrast, cooling the legs in 18°C (64.4°F) and 12°C (53.6°F) water decreased power output 12% and 21% more, respectively. However, higher muscle temperatures also led to quicker fatigue during the sprints. The beneficial effect of temperature was greater at higher pedaling speeds, with a 10% increase in power for every degree (1°C/1.8°F) increase in temperature at the fastest speed.

    It’s important to note that this was a small study that was conducted several years ago. However, the findings suggest that warming muscles before high-intensity exercise enhances power and performance, particularly at faster speeds. This benefit comes with a trade-off of earlier fatigue, potentially limiting endurance activity performance. Cooling, on the other hand, may reduce power output but could extend endurance by slowing the onset of fatigue.

    Interestingly, research shows that warming the body after exercise—in a sauna, for example—can boost performance. In contrast, cCooling the body after exercise may improve glucose and lipid metabolism, decrease inflammation, improve cognitive performance, and enhance immune function — possibly at the cost of reductions in hypertrophy. Learn more in this episode featuring Dr. Rhonda Patrick.

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  • Cold exposure boosts mood and enhances brain connectivity. www.mdpi.com
    Brain Inflammation Depression Cold Stress Norepinephrine

    Cold exposure has long been used to reduce muscle soreness and promote muscle recovery after physical activity. However, evidence indicates that regular cold exposure also improves glucose and lipid metabolism, decreases inflammation, enhances immune function, and improves cognitive performance. Now, findings from a recent study suggest that cold exposure improves mood and increases connectivity between brain networks.

    The study involved 33 men and women who were unaccustomed to regular cold exposure. The participants underwent functional magnetic resonance imaging (fMRI) to assess their brain network connectivity before and after soaking in a cold water (20°C, 68°F) bath. They also reported on their mood before and after the intervention.

    The participants reported feeling more active, alert, attentive, proud, and inspired after the cold exposure. The fMRIs revealed that the participants' positive moods correlated with increased connectivity in the default mode, frontoparietal, salience, and visual lateral networks, regions of the brain that contribute to self-reflection, attention, emotion regulation, and visual processing.

    The findings from this small study suggest that short-term cold exposure improves mood by enhancing brain connectivity in regions associated with mood. These benefits may arise from the effects of norepinephrine, a neurotransmitter involved in vigilance, focus, attention, and mood. Norepinephrine release is one of the most consistent and profound physiological responses to cold exposure. Learn more about cold exposure and the mechanisms that drive its effects in our comprehensive overview article.

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  • Heat shock proteins enhance elite cyclists' performance in low-oxygen conditions. www.sciencedaily.com
    Exercise Performance Heat Stress Cold Stress Hypoxia

    During exposure to temperature extremes or hypoxia (low oxygen levels), cells increase their expression of heat shock proteins to stabilize unfolded proteins and repair damaged ones. This phenomenon, referred to as the heat shock response, occurs at the expense of other cellular proteins to protect the cell. Evidence from a 2016 study suggests that the heat shock response enhances athletic performance in low-oxygen environments characteristic of high altitudes.

    The study involved 21 elite cyclists who engaged in ten 60-minute training sessions in either low-oxygen or hot conditions. Before and after the intervention, they performed a time trial, where researchers tested their tolerance to low-oxygen levels.

    The researchers found that training during heat exposure improved athletic performance nearly as well as low oxygen exposure. Expression of heat shock protein 72 and hypoxia-inducible factor 1-α, a protein that mediates the body’s response to low oxygen levels, increased in both scenarios.

    Heat-shock proteins comprise a large, highly conserved family of proteins that are present in all cells. They play prominent roles in many cellular processes, including immune function, cell signaling, and cell-cycle regulation. Cells maintain a constant level of HSPs to facilitate aspects of the protein synthesis machinery, including assembly, folding, export, turn-over, and regulation. However, stress can upregulate HSP production.

    These findings suggest that training in a hot environment enhances performance in low-oxygen settings. Learn more about heat exposure via sauna use in our comprehensive overview article.

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  • Chronic cold exposure reduces tumor growth by 80 percent and doubles survival rates in mice. www.newscientist.com
    Cancer Cold Stress Brown Fat

    Cancer treatments often target glucose uptake to impede tumor growth, primarily through pharmaceuticals, many of which exert considerable side effects. However, cold exposure is emerging as a potential alternative to these drug-based therapies. A recent study in mice found that cold exposure reduced tumor growth by 80 percent and increased survival rates twofold.

    Researchers conducted a two-part study in mice and humans. First, they exposed mice with cancer to cold (4°C, 39°F) or thermoneutral (30°C, 86°F) temperatures for about three weeks. They found that the cold exposure activated the animals' brown fat, depleting the energy supply available to the tumors. The cold-exposed mice exhibited marked tumor growth inhibition and a nearly twofold increase in survival rates relative to the thermoneutral mice. Interestingly, when they fed the cold-exposed mice a high-glucose diet, the animals did not experience the same extent of tumor growth inhibition, suggesting that glucose scarcity was pivotal in suppressing cancer growth.

    In the second part of the study, they exposed healthy people to cool temperatures (16°C, 61°F) for two to six hours per day for 14 days and found that the participants experienced brown fat activation similar to the mice. Then, they exposed a person with Hodgkin’s lymphoma to cool (22°C, 71°F) temperatures for seven days and found that the participant exhibited activated brown fat and their tumor showed diminished glucose consumption, suggesting the findings in mice translate to humans.

    These findings suggest that cold exposure activates brown fat, reducing blood glucose and impeding tumor growth. Brown fat is a thermogenic (heat-producing) tissue. Studies in animals and humans suggest that brown fat can improve glucose and insulin sensitivity, increase fat oxidation, and protect against diet-induced obesity. Cold exposure increases brown fat volume and metabolism and drives glucose uptake. Learn more about cold exposure and its effects on brown fat in our overview article.

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  • Cold treatment and sympathetic nervous stimulation increases T Regulatory cells (Tregs) in fat tissue: brown fat most of all, visceral least www.sciencedaily.com
    Immune System Cold Stress Norepinephrine Brown Fat Visceral Fat

    From the article:

    The number of obese people as well as those suffering from type 2 diabetes is increasing worldwide. Both disorders are associated with metabolic changes including amplified inflammatory responses in adipose tissue. “Previous studies have indicated that immunosuppressive regulatory T-cells – or Tregs for short – play an important role in these processes,”[…]

    [They] determined that the number of Tregs in adipose tissue increases in response to different environmental stimuli. These stimuli included a short-term cold treatment, stimulation of the sympathetic nervous system (beta-3-adrenoreceptors) or short-term high-caloric exposure. “All these stimuli supported those immunosuppressive cells directly in the adipose tissue,”

    T regulatory cell response to cold and adrenaline reduced in visceral fat:

    The magnitude of the increase in Tregs differed depending on the type of adipose tissue: it was particularly pronounced in brown fat, somewhat weaker in subcutaneous fat and weakest in visceral fat.

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  • Winter-swimming alters thermogenesis and resting metabolic rate. www.sciencedaily.com
    Cold Stress Sauna

    Traditional Scandinavian culture promotes sauna bathing, sometimes combined with brief periods of winter-swimming. This exposure to extreme cold promotes the formation of brown adipose tissue, which may enhance metabolic health. Findings of a new report show that winter swimmers have an increased metabolic response to cold temperatures.

    Brown adipose tissue is a type of fat involved in thermogenesis – the production of body heat. Cold-induced thermogenesis involves uncoupling of the mitochondrial electron transport chain, reducing the efficiency of ATP synthesis. This less efficient mode of energy production consumes more calories than normal ATP production and gives off heat as a byproduct. Brown fat activity contributes to overall energy expenditure and the regulation of body fat. Previous research has reported an association between increased brown adipose tissue and better whole-body glucose and insulin sensitivity in adults.

    The authors recruited eight young, healthy males between ages 18 and 35 who participated in winter swimming two to three times per week. Seven participants also used sauna bathing during their winter swimming practice. The authors recruited an additional eight participants who did not participate in winter swimming or sauna bathing and who were matched for age, body mass index, and maximal metabolic rate. The participants provided a blood sample and completed an oral glucose tolerance test to measure glucose sensitivity. The researchers measured body temperature using infrared thermography, body composition using x-ray absorptiometry, and oxygen consumption during a strenuous cycling exercise, a measure of maximal metabolic rate. Finally, the participants completed a sleep study to determine the effects of circadian rhythm on brown adipose tissue metabolism.

    Winter swimmers had a lower core body temperature and reduced uptake of glucose by brown adipose tissue at a comfortable room temperature. They also had lower plasma glucose levels at the end of the glucose tolerance test, suggesting better glucose utilization by skeletal muscle and adipose tissue. When exposed to cold, winter swimmers had a greater increase in thermogenesis compared to participants who did not participate in winter-swimming. Finally, during the sleep study, winter swimmers had increased thermogenesis a few hours prior to waking. Combined with a lower body temperature, these fluctuations in body temperature during the night may improve sleep quality; however, the authors did not measure this variable in the current study.

    The authors conclude that winter-swimming combined with sauna bathing has distinct effects on thermoregulation at room temperature and upon cold exposure. These alterations in metabolism may improve health through increased resting metabolic rate and improved sleep quality. The authors noted that because participants participated in both sauna bathing and winter-swimming, it is not possible to attribute these differences to cold exposure alone.

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  • Circadian rhythms influence brown fat activity. www.nature.com
    Cold Stress Brown Fat

    Circadian rhythms – the body’s daily cycles of biological, hormonal, and behavioral patterns – play critical roles in human health. Disturbances in these rhythms may increase susceptibility to metabolic disorders, such as diabetes and obesity. Findings from a new study indicate that diurnal circadian variations in brown adipose tissue activity may contribute to metabolic disorders.

    Brown adipose tissue is a type of fat involved in thermogenesis – the production of body heat. There are two types of thermogenesis: diet-induced and cold-induced. Diet-induced thermogenesis involves an increase in the metabolic rate that occurs after consuming a meal. Cold-induced thermogenesis involves uncoupling electron transport from ATP synthesis and repetitive, non-productive transport of ions across the adipose cell membrane. In the past, scientists believed that brown fat was present only in newborns, where it served to protect against heat loss via cold-induced thermogenesis. However, recent research has identified active brown fat in adults, typically following cold exposure. Brown fat activity contributes to overall energy expenditure and the regulation of body fat.

    The authors of the study conducted a two-part investigation. In the first part, 21 healthy men (20 to 50 years old) underwent positron emission tomography (PET) scans to detect the presence of brown fat. During the PET scans, the men sat in a cool (66°F, 19°C) room for two hours while wearing lightweight clothes (a T-shirt and shorts) and periodically placing a towel-wrapped block of ice against the soles of their feet. The authors of the study categorized the men as having high or low quantities of brown fat. Then the men ate a standardized meal, and the authors of the study measured several parameters of the men’s metabolic function, including energy expenditure, diet-induced thermogenesis, and fat oxidation.

    They found that men with high quantities of brown fat tended to have higher diet-induced thermogenesis and fat oxidation than those with low quantities, especially after breakfast, suggesting that brown fat has a greater influence on diet-induced thermogenesis earlier in the day.

    In the second part of the study, the authors categorized 23 healthy men (20 to 29 years old) as having high or low quantities of brown fat using the same procedure used in the first study. Then they used a thermal imaging camera to measure the men’s skin temperature at the supraclavicular region (just above the collar bones, an area where brown fat is typically present). They took measurements in the morning and evening in warm (80°F, 27°C) conditions and after the men had been sitting for 90 minutes in cool (66°F, 19°C) conditions. They also measured the men’s energy expenditure, cold-induced thermogenesis, and fat oxidation.

    They found that the men’s energy expenditure, fat oxidation, and supraclavicular temperature were higher in the men with high quantities of brown fat compared to those with low quantities. The men’s energy expenditure in the morning was nearly equal for both high and low brown fat groups in warm conditions, but it was higher in cool conditions among those with high brown fat quantities. Energy expenditure in the evening was the same among both groups regardless of temperature. Cold-induced thermogenesis among the men with high brown fat quantities was higher in the morning than in the evening.

    These findings suggest that brown fat activity exhibits diurnal circadian variations that influence metabolic function. These variations may explain associations between meal timing, obesity, and related metabolic disorders. Time-restricted eating resets the circadian clock to promote metabolic health. Learn more about time-restricted eating in our overview article.

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  • Beige fat protects against dementia by reducing visceral-like properties of subcutaneous fat www.sciencedaily.com
    Brain Dementia Cold Stress Visceral Fat

    The color of fat tissue – white, brown, or beige – dictates the role the tissue plays in the body. Whereas white fat is involved in lipid storage and the release of free fatty acids for energy, brown fat is involved primarily in thermogenesis – the production of heat. Beige fat, which is typically co-located with white fat, can exhibit either storage or thermogenic properties, depending on environmental conditions. It also exerts anti-inflammatory properties via induction of interleukin 4, an anti-inflammatory molecule. White fat can convert to beige fat, a process known as “beiging.” Findings described in a recent report suggest that beige fat mediates the neuroprotective effects of subcutaneous fat.

    Subcutaneous fat, which is composed of both white and beige fat, is stored just beneath the skin. Commonly associated with a “pear” shape, it may protect against dementia. Visceral fat, on the other hand, is composed of white fat. It is stored in the abdominal cavity close to internal organs such as the liver, pancreas, and intestines. An excess of visceral fat, often referred to as central obesity or abdominal obesity, is commonly associated with an “apple” shape and an increased risk for chronic disease, including dementia.

    The authors of the report conducted a two-part study using a type of mouse genetically modified to lack the gene that promotes beiging. Without beiging, subcutaneous fat behaves more like visceral fat.

    In the first part of the study, they fed either a low-fat or high-fat diet to the genetically modified mice and normal mice for one month. They tested the animals' cognitive function and measured markers of inflammation and immune activation. Both groups of mice became obese on the high-fat diet, but cognitive tests revealed that the mice without beige fat showed signs of early cognitive impairment while the normal mice did not. The mice without beige fat also exhibited rapid, robust inflammatory responses to the high-fat diet, including activation of microglial cells (a type of immune cell found in the brain). Microglia activation promotes inflammation, harms brain health, and contributes to dementia.

    In the second part of the study, the authors transplanted subcutaneous fat from young, lean healthy mice into the abdominal areas of the obese, cognitively impaired mice. The recipient mice experienced improvements in memory and synaptic plasticity – the ability to form new connections between neurons.

    These findings suggest that beige fat drives the neuroprotective and anti-inflammatory effects of subcutaneous fat in mice. A growing body of evidence suggests that cold exposure promotes beiging of white fat. Learn more about the health effects of cold exposure in our overview article.

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  • Brown fat is linked with lower risk of some chronic diseases. www.sciencedaily.com
    Obesity Cold Stress Brown Fat

    Obesity, or having excess body fat, is a known risk factor for a wide range of diseases, including diabetes, cancer, and dementia. Findings from a new study indicate that having brown fat is linked with lower risk of some chronic diseases.

    Brown fat, also known as brown adipose tissue, is found in all mammals and is particularly abundant in newborns. Unlike white fat, brown fat is a metabolically active tissue that is rich in mitochondria. It helps maintain body temperature during cold exposure, during which its uptake of glucose is eightfold higher than that of muscle tissues.

    The authors of the retrospective case-control investigation reviewed imaging reports from more than 52,000 adults who had undergone diagnostic positron emission tomography (PET) scans (nearly 135,000 total scans). They also reviewed the participants' health records.

    The PET scans revealed that nearly 10 percent of the study participants had detectable brown fat. Those who had brown fat were less likely to have type 2 diabetes, abnormal lipid levels, coronary artery disease, cerebrovascular disease, congestive heart failure, and hypertension. They were also more likely to have favorable blood glucose, triglyceride, and high-density lipoprotein levels. These effects were greatest in people who had obesity or overweight. The authors suggested that having brown fat might counteract some of the harmful effects of obesity.

    These findings indicate that brown fat may protect against some diseases and suggest that adopting lifestyle behaviors that promote production of brown fat, such as exercise or cold exposure, may be beneficial. Some nutrients and bioactive compounds, such as curcumin, capsaicin, resveratrol, and omega-3 fatty acids, may increase brown fat production, too.

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  • Post-workout ice baths may hinder muscle protein synthesis www.sciencedaily.com
    Muscle Cold Stress Protein

    Post-workout ice baths and increased dietary protein intake have long been used by athletes as strategies to build muscle. Findings from a new study suggest that ice baths may hinder muscle protein synthesis by interfering with dietary protein uptake into muscles.

    The study participants included 12 healthy young men who engaged in a single resistance‐type exercise session and then immersed both their legs in water for 20 minutes. One leg was immersed in cold water (8°C, 46°F) while the other leg was immersed in water that was slightly warmer than room temperature (30°C, 86°F). Afterward, the participants consumed an amino acid-rich beverage.

    The authors of the study monitored the uptake of the amino acids and subsequent muscle protein synthesis for two weeks. Analyses of blood, saliva, and muscle tissue revealed that cold water immersion after resistance‐type exercise reduces muscle protein synthesis, which could impair muscle conditioning.

    Interestingly, an older study found that cold water immersion reduced the risk of cancer and enhanced longevity in mice. The contradictory findings of these two studies suggest that cold exposure may be harmful in certain contexts, but beneficial in others, and that timing of the exposure is critical.

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