Surviving extreme summer heat: Tips from 4 experts
August 9, 2024
Craig Crandall, Ph.D., Professor of Internal Medicine in the Division of Cardiology, contributed to this story.
The scorching heat can be inescapable at this time of year. As temperatures hover around triple digits, it’s important to be mindful of how extreme heat can affect our bodies, both inside and out.
Extreme heat typically refers to temperatures above 90 degrees with high humidity. Although this can seem like the norm in some regions, prolonged exposure can have dire health consequences. In fact, the U.S. Environmental Protection Agency calls heat “the leading weather-related killer” in the country. From 2021 to 2023, the number of heat-related deaths in the U.S. jumped from 1,602 to 2,302, according to the U.S. Department of Health and Human Services.
Heat waves can impair bodily functions and, in a worst-case scenario, cause organ failure. Meanwhile, strong UV rays from the sun can be harmful and increase the risk of skin cancer.
How heat impacts the body
- Heart – During heat stress, blood rushes to the skin to release body heat. The heart must work harder to pump blood, which can be especially harmful for people with cardiovascular disease.
- Blood flow – Some blood vessels will constrict, and as blood is diverted to the skin, vital organs could be starved of oxygen supply.
- Gut – The intestinal tract becomes more permeable as the body overheats, allowing potentially harmful substances like toxins to enter the bloodstream.
- Muscles – When people overexert in extreme heat, they may strain their muscles and develop cramps. In severe cases, a muscle may even break down — a condition known as rhabdomyolysis.
- Kidneys – Dehydration and impeded blood flow can impair kidney function. Patients who have renal disease face a greater risk when exposed to extreme heat.
- Lungs – When people become overheated, they tend to breathe harder, and a greater demand is placed on the lungs. Hot and humid air also can trigger or exacerbate asthma symptoms.
Heat exhaustion vs. heat stroke
Two of the biggest concerns are heat exhaustion and heat stroke.
While heat exhaustion is not likely to inflict significant damage if addressed early, heat stroke is far more dangerous. By then, your body temperature has risen so much that organs, such as the brain, are shutting down.
There’s no official body temperature that denotes heat stroke, but the higher it climbs, the greater the cause for concern. It is widely considered life-threatening when a person’s temperature reaches 104 degrees. Recognizing the symptoms of heat stroke is important. The goal is to cool the body as fast as possible.
Certain populations are more vulnerable to extreme heat than others including older adults, children, and pregnant women. Some medications might also interfere with the body’s thermoregulatory process. Drugs known as anticholinergics, which treat a range of conditions, can suppress sweating. Other drugs that are commonly used to treat hypertension can lower blood pressure or have a diuretic effect. If you’re not staying cool and appropriately hydrated, these medications can exacerbate the effect of the heat with dizziness and dehydration.
Common symptoms of heat exhaustion:
- Headache or dizziness
- Nausea
- Weakness
- Irritability
- Heavy sweating
- Elevated body temperature
Major signs of heat stroke:
- Confusion/Delirium
- Agitation
- Slurred or nonsensical speech
- Seizures
How to stay safe in the heat
While the weather is out of humans’ control, we can take preventive measures to protect ourselves during the summer. Here are some tips from the experts at UTSW:
- Stay hydrated – The body needs water to function properly, so it’s recommended to have a bottle of water on hand when venturing outside during the summer. Athletes and others who expend a lot of energy for long periods may benefit from drinks with added electrolytes.
- Take breaks – The brain will signal when it is in distress. When you begin to feel fatigued, dizzy, or overheated while working outside, go indoors to rest. Take advantage of shaded areas and drink plenty of water.
- Dress appropriately – Wear clothes made of lightweight fabric. The idea is to choose clothes that are conducive to sweating.
- Monitor the heat index – Sometimes the best solution is the simplest. Stay indoors during the hottest time of the day and when there’s a heat advisory. Make sure your air conditioning system is working properly and know where you can find a cooling center in case of emergency.
- Use wet cloths – One method of cooling down is to wipe your skin with a wet cloth. In some cases, this is a better option than fans. While fans may be useful, once the temperature approaches 100 degrees, it could do more harm than good, particularly to older adults.
- Ease into summer – Allow yourself time to acclimate to the heat. The more time you spend outside during the summer, the more bearable the heat becomes as your body adapts.
- Check on each other – Although most cases of heat-related deaths are preventable, the biggest threat is a lack of access to air conditioning, which primarily affects people who are homeless or living in a low-income household. To address this issue, many local agencies – including the City of Dallas Office of Homeless Solutions – offer temporary cooling stations when heat advisories are in effect. More information about resources can be found on the city’s website. It’s also recommended that families check on older relatives who live on their own.
When sunlight becomes harmful
It’s well known that the sun’s ultraviolet (UV) rays can wreak havoc on the skin. But most people don’t realize some commonly used products and medications can make us more susceptible to sunburn and other adverse reactions.
Common signs of photosensitivity include rashes, itchiness, inflammation, or sunburn-like symptoms and skin irritations. Although these symptoms typically resolve on their own, exposure to UV light could heighten the risk of lasting damage or skin cancer.
Certain drugs – whether oral, topical, or injection – contain ingredients that can trigger a physical reaction when the skin is exposed to UV light, according to the U.S. Food & Drug Administration. Blood pressure medications and some antibiotics, such as ciprofloxacin and doxycycline, interact with ultraviolet radiation and convert into a chemical byproduct that can directly damage skin cells and cause sunburns.
Some cosmetic creams and other beauty products, such as retinol serums and skin exfoliants, can increase photosensitivity. Scan product labels for ingredients such as alpha and beta hydroxy acids, used for their antiaging properties, which may render the skin more tender and oversensitive.
While many brands of makeup now incorporate sunscreen, effective protection often requires a greater amount of product than most people use. The best option for sun protection is to apply a layer of sunscreen underneath the makeup.
Avoid ‘margarita burn’
Another substance capable of triggering a toxic skin reaction can be found in many kitchens and bars: the lime.
Certain plants including limes contain chemical compounds known as furocoumarins, which are activated when exposed to sunlight and then destroy cells.
Colloquially dubbed the “margarita burn” because the popular cocktail often comes with a lime wedge, this phototoxic reaction known as phytophotodermatitis can cause itchy rashes, swelling, and fluid-filled blisters, which typically emerge one to two days after exposure and last for days. Other citrus fruits such as lemons and grapefruit can induce phytophotodermatitis.
4 tips to enjoy the outdoors
- Apply sunscreen liberally: A general rule of thumb is 2 tablespoons or 1 ounce for an adult’s body. Reapply every time you get out of the water or towel off.
- Choose broad-spectrum SPF 30: It provides protection from UVA and UVB light, both of which can lead to skin cancer.
- Wear long-sleeve clothing: Sun shirts with ultraviolet protection factor (UPF) can help block UV rays.
- Seek shade and avoid tanning beds: Limit exposure to natural and artificial sources of UV light.
