Data from the United States show that an increase in days 90 degrees and above is associated with an average of 1,373 extra deaths each year.² Meanwhile, research published in 2023 estimated that more than 61,000 people died from heat-related causes in Europe between May 30th and September 4th 2022, Europe’s hottest summer on record. Elderly people—especially women—were the most affected.³ Infants and young children, pregnant women, those with chronic medical conditions, athletes, outdoor and agricultural workers, and lower-income populations are also more vulnerable to extreme heat.⁴ But our bodies have an incredible ability to adapt to our environments, and this is true with building adaptability and resiliency to heat.

What extreme heat does to the body (why is it so dangerous?)

We’ve all been overheated at one time or another, but there is a point when the exposure to extreme heat becomes dangerous. When we sweat the heat from our body causes some of the moisture to evaporate off the body. Using up some excess body heat helps cool the body and regulate temperature. But sweating profusely for an extended period can lead to dehydration (and electrolyte loss), which can make it harder for the body to maintain normal blood pressure, putting strain on your heart and kidneys. Extreme heat can create more heat inside the body, making it hard for the heart, lungs, and brain to function properly. The most extreme version of this is heat stroke, in which the body’s temperature rises too rapidly and the body is unable to cool down; left untreated, heat stroke can damage organs, and in worst cases, cause them to shut down, leading to death.⁵ But most heat-related deaths aren’t caused by heat stroke, but rather, heart attacks or some other cardiovascular event. When our bodies heat up, the heart is the main organ working to cool us down by pumping more blood to the surface of the skin to release excess heat. This extra strain on the heart—especially in those with poor cardiovascular health or older individuals—can be deadly.⁶

Build Your Resilience to Heat

Herbal Air-Conditioning

Herbalists have long understood that herbs (and foods) have heating, cooling, or neutral properties. This is different than the actual temperature of something—whether it feels warm or cool to the touch—and instead about the effects the herb will have on your tissues. There are numerous herbs that have cooling effects, but some that are widely available and easy to incorporate into your routine include: peppermint, spearmint, nettle, fennel, lemon balm, lavender, chamomile, catnip, lemongrass, and hibiscus. You can use them as spices in your cooking and look for teas that contain some of these herbs and drink them cool if desired. You can also use tinctures or capsules of herbs. It can be especially nice to choose cooling herbs that have medicinal properties that line up with your health goals. For instance, fennel soothes digestion, while lemon balm acts as a mild sedative.

Essential oils are another good way to harness the cooling energy of herbs for topical purposes. Look for soaps, lotions, lip balms, and sprays with peppermint, eucalyptus, lavender, and/or rosemary.^{7 8} Rose is another herb valued for its cooling effects. Using rose hydrosol and/or rose essential oil topically can be cooling and also beneficial for all skin types, but especially mature and sun-damaged skin. These essential oils and hydrosols (aka flower waters) are not only cooling, but you’ll be reaping the skin and mood benefits of the essential oils as well. 

Check out this DIY Post-Sun Aloe Spray.

Not only is it full of cooling ingredients, but it supports skin stressed by the sun. Store it in the fridge for extra cooling effect.

Cool as a Cucumber Salad

Without much thought, most of us naturally start craving cooling, lighter foods with a higher water content when it is hot outside. If it’s 90 degrees and you’re sweating, a light salad probably sounds a lot better than a big plate of pasta with Bolognese sauce. In general, foods that grow above ground in mid to late summer and are higher in water content are naturally cooling. Think cucumbers, melons, berries, leafy greens, green beans, jicama, tropical fruits, cilantro, etc. Chilies are a gray area; while they grow in hot weather and can induce sweating, which helps cool us, Traditional Chinese Medicine and Ayurveda both consider them to be heating, and thus something to minimize when it is hot outside. Heating foods like ginger, garlic, fermented foods, processed foods, and heavy carbs should be minimized. For a cooling effect, favor seasonally available foods prepared simply (raw, steamed, stir-fried) and flavor with cooling spices. You can also keep coconut water on hand for a drink as replenishing after a bout of exercise and sweating as commercial sports drinks, but without all the sugar and artificial stuff.⁹

Take a Chill Pill

We generally don’t think of vitamins, minerals and individual amino acids as heating or cooling, but there are some that can help us adapt to the additional stress hot weather can put on our bodies and help to replenish what’s lost when we are sweating a lot.

Vitamin C

Vitamin C is probably the best researched vitamin for helping the body acclimate to the heat. It has been studied and used for this purpose since the 1950s. Taking vitamin C helps to reduce the strain from heat, reduce heat exhaustion when working in a hot environment, and helps the body get more used to heat. Studies have used anywhere from 250 mg to 2,000 mg a day for this purpose.^{10 11 12} Vitamin C also appears to help relieve heat rash (aka prickly heat or miliaria rubra) and prevent further bouts.¹³

B-vitamins

B-vitamins are not only lost in sweat but may also help the body acclimate to the heat. In one study, a high potency B-complex reduced fatigue when given to high school male athletes exercising in a hot environment.¹⁴ Older adults may also benefit from additional folate. The vascular function of the skin tends to decrease as we age, which can impair the body’s ability to cool itself. Five milligrams of folic acid daily for 6 weeks improved skin vasodilation in response to a whole-body heat test in older subjects to levels similar to those of young adults.¹⁵

Magnesium

Magnesium is believed to play a role in body temperature regulation, and it is also lost in sweat, making the demand for magnesium especially high in hot weather.¹⁶ Without an adequate supply of magnesium, the body may not be able to properly thermoregulate.¹⁷

Electrolytes

Electrolytes (sodium, potassium, magnesium, and calcium) may be especially important if you’re sweating a lot, since they are lost in sweat. The electrolytes are critical for maintaining fluid balance in and out of the cells and for nerve impulses and muscle contractions. 

Tyrosine

Tyrosine, an amino acid, is sometimes touted for helping the body adapt to heat stress. While the research has been mixed, one review found that tyrosine in varying doses may benefit cognitive performance in heat stress conditions.¹⁸ 

Building heat resiliency has become something that modern humans have to do in a warming world. Common sense measures are critical, like staying hydrated!; if you can’t be inside in air conditioning, find shade; wear loose-fitting, breathable clothing; don’t exercise or exert yourself in extreme heat conditions (this is especially true for those with existing conditions and older people); and give your body time to acclimate—spend a short time outside in the hottest part of the day for several days to let your body become accustomed to the heat. Beyond that we can build our resilience to heat with food, herbs, supplements and just plain old supporting overall health.  

Want to Beat the Heat? Get Moving!

Exercising may be the last thing you want to do when it’s very hot outside—and of course you shouldn’t push yourself in extreme temperatures—however, a lifetime of regular physical activity can go a long way in helping our bodies adapt to heat and support good cardiovascular health. Research published in late 2023 says that “By frequently increasing core temperature and sweating, as well as stimulating the cardiovascular system, regular physical activity … in temperate conditions leads to several physiological adaptations that increase heat tolerance and help in meeting the increased demands placed on the cardiovascular system during heat stress.” It goes on to say that regular physical activity in a hot environment provides “even greater and additional” heat adaptations, including “a lowered resting core temperature, improved vasodilation in the skin (this helps release heat), increased sweating capacity, improved cardiac function, expanded blood volume, and enhanced cellular protection.” The researchers point out that this is especially important for today’s youth, who will be more exposed to extreme heat in the future. “By maintaining regular physical activity and adequate physical fitness throughout their lives, they may be better equipped to meet these challenges.”¹⁹

References