Heat Dome Could Kill You and Simple Hacks to Keep Your Cool (2025)

By Editorial Team - July 29, 2025

A heat dome is a weather phenomenon consisting of extreme heat that is caused when the atmosphere traps hot air as if bounded by a lid or cap. Heat domes happen when strong high pressure atmospheric conditions remain stationary for an unusual amount of time, preventing convection and precipitation and keeping hot air "trapped" within a region. (Wikipedia)

Summer is in full swing, and with it comes the hot weather. And sometimes, these periods become unusually hotter. In fact, experts have dubbed this phenomenon as “heat domes,” putting many people at risk for heat-related diseases.

What Exactly Is a Heat Dome and Why Is This One Dangerous?

You may have noticed that news programs are now sending out advisories about heat domes settling around the Eastern and Midwestern United States during the last week of June 2025.

•What are heat domes? In an interview with WAMU 88.5, meteorologist Jason Samenow explains what these phenomena are:1

“Heat dome just refers to a large area of intense high pressure. Underneath the heat dome, the air sinks … it warms up. Oftentimes it’s accompanied by high humidity, so that combination can bring pretty punishing temperatures and conditions, especially for vulnerable groups: outdoor workers, older adults, and anyone without access to air conditioning.”

•Heat domes are now more common — Samenow shares that more heat domes are expected based on previous patterns:2

“This heat dome is kind of part of the new normal. Last summer was one of our hottest summers on record. We had multiple heat domes just like this last year. I think we had six days reach 100 [degrees F] last year and most of our hottest years on record have all occurred in the last decade.”

•Unusual temperatures — According to a report by FOX 5, the heat dome will allow “relentless sunshine to bake the region day after day.”3 Specifically, temperatures will reach as high as upper 90 degrees Fahrenheit, but humidity will cause it to reach 105 to 110 degrees Fahrenheit.

•Heat domes can bring about health problems — What makes heat domes this year worrisome is that certain areas are experiencing triple-digit temperatures that haven’t been seen in more than a decade. For people who live in the affected areas, health concerns are likely to occur because they haven’t adapted to warmer weather yet.4

•The lifespan of a heat dome — While the presence of heat domes in the atmosphere is alarming, fortunately they don’t last a long time. According to meteorologist Joseph Bauer, heat domes only last for a few days, but can extend to weeks at the most.5 Still, proper precautions need to be taken to protect public health.

Hydration — A Cornerstone of Sweating Properly

Sweating is one of the most important ways your body maintains optimal temperature. Without it, your body temperature will keep on rising until damage occurs to your organs. However, sweating too much is also not advisable, as it can lead to dehydration.

•Composition of sweat — About 99% of your sweat is water. The remaining 1% is composed of sodium and chloride, which is what makes up table salt (the reason why sweat tastes a little salty). Moreover, sodium is a crucial electrolyte that maintains proper bodily functions.6

•Sweat is mostly water drawn from your bloodstream — Lose even 1 % of body mass through your fluid and your sweat rate drops; core temperature soars even though you feel just a little thirsty, and this is usually experienced during exercise. As detailed in the book “Fluid Replacement and Heat Stress”:7

“A water deficit of only 1% of body weight significantly elevates core temperature during exercise. It is believed that as the severity of hypohydration increases, there is a concomitant gradation in the elevation of core temperature during exercise.”

•Other functions of sweat — Beyond cooling your body, sweat also helps clear excessive micronutrients from your body, remove waste products produced by your metabolic processes, and expels toxins such as heavy metals.8

•The importance of staying hydrated — Drinking enough water throughout the day gives your body enough reserves to be able to sweat properly, especially during the summer. If you’re dehydrated and your body can’t sweat anymore, various health problems will appear.

For example, excessive loss of electrolytes results in muscle cramps, especially if you’ve been sweating profusely outdoors from exercise.9 A higher body temperature also places significant strain on your cardiovascular system.10

•Spotting signs of dehydration — If you’re not getting enough fluids into your system, you will notice these indicators of dehydration:11,12
Dry, sticky mouth, Bad breath, Chills, Sleepiness or tiredness, Decreased alertness and fatigue, Dizziness or lightheadedness, Headache, Confusion, Constipation, A decline in athletic performance, Few or no tears when crying, Minimal amount of dark-colored urine, Dry, cool skin, Sugar craving, Muscle cramps.

Hydration guidelines — I recommend you drink half of your bodyweight (pounds) in ounces of water daily during a heat wave. If you’ve already sweated a lot, add a pinch of sea salt or an electrolyte packet per quart to keep your electrolyte levels at the optimal range. Remember, if you’re not sweating, your body cannot cool itself.

If there are no heat domes in your area, there are other ways to tell if you need to drink more water — thirst and urine. Simply put, thirstiness is your body’s way of telling you that it needs more water. The color of your urine is also a strong indicator — a pale straw or light-yellow color indicates proper hydration, whereas dark yellow or amber-colored urine suggests dehydration.

Arteriovenous Anastomoses — Your Built-In Radiators

Sweating is more than just a surface-level biological process facilitated by your sweat glands. Deep under your skin are arteriovenous anastomoses (AVAs), which are short, thick pipes that link arteries directly to veins.

•Where your AVAs are located — When your hypothalamus senses overheating, it dilates your AVAs, flooding blood into your hands, feet and face where the skin is thin and loaded with sweat glands. A study published in Temperature: Multidisciplinary Biomedical Journal explains this process in greater detail:13

“When the ambient temperature is below the lower end of the thermoneutral zone, all AVAs are closed. Above the upper end of the thermoneutral zone they are probably open most of the time, but this is of little importance, since the vasodilatation caused by cholinergic mechanisms related to sweat production results in a large increase in blood flow to all skin areas.”

•The role of AVAs in keeping your body cool — The researchers explained how AVAs under your skin support the sweating process:14

“The AVAs play an important role in temperature regulation in humans in their thermoneutral zone, which for a naked resting human is about 26°C to 36°C, but lower when active and clothed. From the temperature control center in the hypothalamus, bursts of nerve impulses are sent simultaneously to all AVAs.”

•Your limbs contain the AVAs — The extremities are AVA-rich zones that help your body cool down:

“As the ambient temperature rises, more blood is returned through the superficial venous plexuses and veins and heats the skin surface of the full length of the four limbs. This skin surface makes up about 50 % of the body surface and is responsible for a large part of the loss of heat from the body toward the upper end of the thermoneutral zone.

Thus, the AVAs of the hands and feet and the superficial veins of the limbs may be regarded as a single entity responsible for control of body temperature in most ordinary situations.”

In addition to staying hydrated, you can open up your AVAs and stay cool by using this towel‑plus‑fan trick:

Soak a small cotton towel in cool tap water.
Drape it over wrists, palms, or the back of your neck.
Aim a box fan or desk fan so the towel flaps slightly.

Why use a fan? The airflow erases the humid boundary layer that smothers evaporation, allowing heat to be dissipated faster. This allows your sweat to evaporate and why is that so important?

Because there a phase change occurs and when water transitions between liquid and gas phases it takes along with it enormous amounts of energy. So much so that you cool down up to four times faster when you evaporate your sweat with a strong fan.

Sunlight Exposure, Vegetable Oils, and Skin Damage

In addition to heat, the linoleic acid (LA) embedded in your skin is a significant contributor to cellular stress during periods of high temperatures. Once they lodge in your cell membranes, they oxidize the moment sunlight hits your skin, generating a free‑radical chain reaction that ages skin and drives DNA mutations. Thus, removing LA from your body becomes of great importance for your overall health.

•The link between skin cancer risk and fat intake — In a study published Cancer Epidemiological Markers, researchers noted that increased fat intake, especially from omega-6 polyunsaturated fat (PUF), has been linked to an increased risk of squamous cell carcinoma (SCC):15

“Using the data from two large prospective studies of women and men in the US, we found no association of fat intake with melanoma except for omega-6 fat intake. For SCC, we found higher risk associated with higher intake of polyunsaturated fat and omega-6 fat,” the researchers said.

•Sources of LA — Canola, soy, corn, sunflower and “vegetable” oils are the most common sources of LA. Purge them for at least eight to 12 weeks so old PUFs can be metabolized out of your system.

•A way to hasten LA removal from your skin — In the course of my research, I learned that C15:0 (pentadecanoic acid) can replace the LA entrenched in your skin. C15:0 is chemically stable because it contains no double bonds. In short, this fat is resistant to peroxidation. In contrast, LA easily breaks down into harmful lipid peroxides.16

•Replace LA with C15:0 — As your skin remodels itself, the keratinocytes carry LA with them to the surface. Now, upping your intake of C15:0 makes your keratinocytes use this healthy fat instead of LA.

Taking 250 mg daily may help shorten the time it takes for your skin to safely interact with sunlight again, but emerging research suggests much larger doses may be even better.17

•Recommendations for boosting C15:0 intake — The best sources of C15:0 are dairy products, especially from grass fed cows. In addition, I recommend limiting your intake of LA from ultraprocessed foods, snacks, and beverages — keep it to below 5 grams per day, but if you can keep it below 2 grams, that’s even better.

Finally, ease into sun exposure after your LA stores have been removed because your skin remains vulnerable to ultraviolet-triggered oxidative stress. As you lower your LA intake and add C15:0 into your diet, avoid sun exposure between 10 a.m. and 4 p.m. when radiation is at its peak. This will help you optimize your vitamin D levels while keeping skin damage and heat exposure to a minimum.

When to Call 911

If you’re outside during summertime and you see someone shift from clammy dizziness to confusion or collapse, assume that their core temperature is greater than 104 degrees Fahrenheit. When this happens, call emergency services immediately, and while they’re on the way you can help the person by:

Laying them flat and elevating their legs.
Fanning them aggressively and applying cooling towels on wrists, palms and forehead.

You can shave around 2 degrees Fahrenheit from their core temperature with these tips. While this slight drop may not sound like a lot, it is tremendously helpful already.

Follow This Checklist to Keep Cool This Summer

As seen from the research, exposure to prolonged periods of heat is dangerous to your health. To help you stay cool, refer to the list below, which is a summary of my recommendations:

1.Hydrate like it’s your job — Maintain clear, copious urine during summertime.

2.Soak and fan your AVAs — Do these three to four times a day or any time your skin stops feeling cool.

3.Eat real food and ditch ultraprocessed food — These products contain LA, which contribute to oxidative stress on your skin while you’re out in the sun.

4.Respect the clock — Try to schedule heavy outdoor work before 10 a.m. or after 4 p.m. to prevent excess sweating and intense sunlight exposure while you’re working to purge LA from your tissues.

5.Bring out the fans — Even a simple $20 box fan turns stagnant misery into a breeze‑cooled oasis during summertime. Portable, battery-powered fans are also available while traveling.

Frequently Asked Questions (FAQs) About Heat Domes and Staying Cool This Summer

Q: What exactly is a heat dome, and why are they becoming more common?

A: A heat dome is an area of intense high pressure that traps heat and humidity, causing extremely high temperatures. Heat domes are becoming increasingly frequent and intense, leading to hotter summers and record-breaking temperatures.

Q: Why is hydration so crucial during heat waves?

A: Hydration is essential because sweating cools your body by evaporating water from your bloodstream. Even slight dehydration (just 1% body mass loss) significantly raises your core temperature and leads to muscle cramps, cardiovascular stress, dizziness, and other health problems.

Q: How much water should I drink during a heat wave?

A: Drink approximately half your body weight (in pounds) in ounces of water daily during a heat wave. Adding a pinch of sea salt or electrolyte packets can help maintain optimal electrolyte levels, especially if you've been sweating heavily.

Q: How does diet influence skin damage from sunlight exposure?

A: Dietary intake of omega-6 fats, especially linoleic acid (LA) found in processed foods and vegetable oils, increases skin damage and cancer risk by triggering oxidative stress when exposed to sunlight. Reducing LA intake and increasing consumption of healthier fats, like C15:0 found in grass fed dairy products, significantly reduces this risk.

Q: What should I do if someone shows severe signs of heat illness?

A: If someone appears dizzy, confused, or collapses during extreme heat, immediately call 911. While waiting for help, lay the person flat, elevate their legs, fan them vigorously, and apply cool towels to their wrists, palms, and forehead to help lower their body temperature quickly.

Sources and References

https://articles.mercola.com/sites/articles/archive/2025/07/29/heat-dome-survival-guide-5-cooling-hacks-summer.aspx

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