In the peak of summer’s heat or winter’s chill, it feels good to retreat back into comfortable, climate-controlled settings like your car or home. But did you know that brief and deliberate exposure to temperature extremes has a whole host of benefits? Let's look at some of the ways that getting hot and cold can improve your wellbeing, performance, and recovery.
Though air conditioning and heating technology has undoubtedly made our lives more pleasant day to day – particularly if you live somewhere hot – it has also caused some issues. “[We] lack exposure to varied ambient temperature [because we] cool and heat our dwellings for maximal comfort while minimizing our body energy expenditure necessary to control body temperature,” wrote the authors of a study published in Trends in Endocrinology & Metabolism.
In his book The Comfort Crisis, Michael Easter explained that constantly being in a desirable temperature range can also compromise cellular and brain function, limit our ability to heal and tackle inflammation, and dampen metabolic control. The remedy? Heat and cold exposure.
Feeling Hot, Hot, Hot
In a long-term study of sauna bathing, researchers followed the health of 2,315 Finnish men for almost 21 years. While you might assume that there’s a law of diminishing returns for the health benefits of this kind of heat exposure, these particular results suggest that the more often you do it, the better off you will be. Their daily heart health improved, as death from cardiovascular disease diminished by 27 percent with two or three weekly sauna sessions and 50 percent with four or above.
Men who got in a sauna two or three times a week had 22 percent less chance of sudden cardiac death, and when they upped their use to four to seven times, it was 63 percent lower. Heat exposure also seemed to greatly improve overall wellbeing. All-cause mortality was 24 percent and 47 lower percent for those that used the sauna two to three times a week and four or more times, respectively. Another extensive trialconcluded that people who took four to seven sauna baths weekly had 47 percent less chance of developing hypertension (high blood pressure).
Heat exposure also seems to be beneficial to the brain. The team that examined the link between it and cardiovascular health also discovered that four or more sauna sessions per week lowered the incidence of developing dementia by 66 percent and Alzheimer’s by 65 percent. Some of the same researchers foundthat the risk of suffering from psychosis is 78 percent lower among frequent sauna users and noted that it also lowers the frequency and severity of depression and anxiety symptoms.
Heat shock proteins (HSPs) might be the mechanism for such neuroprotective effects. These increased by 49 percent after a single sauna session, according to a paper published in the Journal of Athletic Training. Other studies have shown how increases in HSPs are often accompanied by a rise in mood-elevating endorphins and brain-derived neurotrophic factor (BDNF), which stimulates new brain cell growth. HSPs also help tame inflammation by interacting with antioxidants and lowering oxidative stress, preserve normal cell function, and help other proteins work well.
Coming to Grips with Cold
One of the most promising results of exposing yourself to chilly temperatures is that doing so activates cold shock proteins (CSPs) that help regulate many processes, including immune function. Czech scientistsnoted that when exposed to cold water immersion (CWI) three times a week, participants increased the number of cells that detect bacterial infections and those that combat them. A previous study had shown that CWI increased the activity of cells that tackle viruses and neutralize cancer.
It might initially feel uncomfortable, but deliberately getting cold can also positively impact mood. A study published in the European Journal of Applied Physiology concluded that CWI increased production of the “happy hormone” dopamine 2.5x and norepinephrine, which is diminished in people with mental health conditions, by 5.3x. The authors of another study released via Biology wrote that “participants felt more active, alert, attentive, proud, and inspired and less distressed and nervous after having a cold-water bath. The changes in positive emotions were associated with the coupling between brain areas involved in attention control, emotion, and self-regulation.”
Cold water also benefits an active body. If you’ve ever seen athletes slide into an ice bath after a game, it turns out they’re onto something. A 2023 paper noted that this reduces the amount and duration of delayed onset muscle soreness (DOMS), allows you to get over fatigue more quickly, and makes your next workout feel easier. Another meta-analysis stated that CWI allows athletes to get their full strength, speed, and power back sooner and also enable a faster bounce back from endurance training. All this being said, waiting until a couple of hours after exercise for cold exposure will stop it from diminishing certain adaptations.
In addition to reducing post-exercise soreness, cold exposure can curb inflammation related to conditions like fibromyalgia and arthritis. Inflammatory markers went down when people got CWI therapy for five days, while their levels of anti-inflammatory activity went up. Another 2022 paper found that cold exposure reduces pain and improves joint mobility for sufferers of gout arthritis.
Cold exposure doesn’t always have to involve getting into ice. Dutch scientists found that just 30 to 90 seconds in a cool shower daily lowered the risk of catching a cold by 29 percent. You don’t even need to get wet to get another advantage of chilling out. The study focused on environmental temperature mentioned earlier found that even downshifting your thermostat a little bit in winter can positively impact fat metabolism and overall calorie burn at rest. “Mild cold exposure increases body energy expenditure without shivering and without compromising our precious comfort,” the authors noted.
Such advantages might be elevated when combined with CWI. One 2022 review asserted that “CWI seems to reduce and/or transform body adipose tissue, as well as reduce insulin resistance and improve insulin sensitivity. This may have a protective effect against cardiovascular, obesity and other metabolic diseases and could have prophylactic health effects.”