I may owe my life to the Colorado River. As an East Coast chick, I naively prepared for a 10-mile hike into the Grand Canyon the way I would for a walk through a forest back home. Do you know about the dangers of heat stroke? I didn’t. The experience left me wondering: How does heat stroke affect the brain?

BTW, pro tip if you ever go hiking in that area: There is zero shade until you reach the river, the sun seldom goes behind a cloud to give you a break, and the dry, desert heat dehydrates you far more quickly than the humid air found in woodlands closer to the coast. Fortunately, I reached the river and the adjacent Native American village in time and was able to both hydrate and take a refreshing dip to cool down.

I later realized how lucky I had been when I read about the number of people who die in the Canyon each year — sometimes from falls, but more often from heat stroke. With summer on the way and temperatures on the rise, everyone benefits from knowing how they can prevent this potentially fatal condition. So, how does heat stroke affect the brain?

Signs and Symptoms of Heat Stroke

Of all the heat-related illnesses that exist, heat stroke is the most dangerous and potentially deadly. Many people first suffer from heat exhaustion or heat cramps before progressing to heat stroke. Over 600 people each year perish as a result of their body temperatures soaring out of control.

When out in the sun, be aware of the following symptoms and head inside to the AC or cool down with water when they first occur. Delaying the cooldown increases the chances of heat exhaustion proceeding to heat stroke. Early signs include:

1. Nausea: Many people report feeling less hungry on hot days, but those out in the sun who start feeling nauseous should cool themselves down. Nausea is often the first sign of heat-related illness. When feeling queasy, head inside, lie or sit under a fan, or press compresses cooled in the freezer on parts of the body where veins run close to the skin, such as the wrists.
2. Headache: Those who suffer from migraine have one advantage: The early signs of heat stroke feel similar to a bad attack. When body heat rises too high, people experience throbbing headaches. Unlike migraine, where the pain usually remains to one side, the entire head may ache and pulse.
3. Dizziness: As heat exhaustion heads toward heat stroke, many start feeling lightheaded. Some even faint, so if outdoors with someone who feels dizzy, get them into the shade or a cooler location quickly. Dizziness can also stem from dehydration, so share the water bottle.

More serious signs that heat stroke has occurred and professional medical attention is needed include:

1. Dry, red skin: Those with heat stroke stop sweating as their bodies lose the ability to regulate temperatures. This is extremely dangerous, as the body can no longer cool itself — it needs outside help.
2. Rapid, shallow breathing and heart rate: As the body heats up, heart rate increases. Those suffering from cardiovascular diseases may experience a heart attack or stroke. Breathing increases as the body tries to expel heat to no avail.
3. Loss of consciousness: Anyone who witnesses someone collapse on a hot day needs to call 911 and get them into the shade, stat, to prevent brain damage. If the individual regains consciousness, press a cool cloth to their lips if they indicate thirst, but refrain from offering water until medical personnel arrives, as this may cause vomiting, dehydrating them even further. If no shady spot exists, fan them with a shirt or any other object that can create a light breeze until help arrives.

How Does Heat Stroke Affect the Brain?

Exactly how does heat stroke affect the brain? When the body loses the ability to regulate its internal temperature, the vital organs swell. In the brain, the configuration of the cranial cavity prevents this expansion. Failure to treat heat stroke quickly can result in permanent brain damage and death.

Magnetic resonance imaging (MRI) of the brains of those who suffered heat stroke differ vastly from others. Excess heat causes the neurons in the brain to start to die, and the extent of neural death determines the severity of ability loss. When too many neurons die, the brain can no longer send the right messages to the heart and other organs to keep them functioning.

Preventing Heat Stroke and Easing the Burn

Given the severity of heat stroke, avoiding the condition proves far easier than treating it. Before heading out, check the weather report. If going on an extended trek, carry more water than necessary. Water helps stave off heat stroke by helping regulate body temperature. The amount of water needed depends on age, weight, gender — menstruating women need more water — activity level and climate.

Take swift action when the first signs of overheating appear. Trying to push through a five-mile run when temps soar into the triple digits can be deadly. Drink before feeling thirsty, and head to a cooler location and slow down activity the moment nausea, headache or dizziness occurs.

Watch for heat stroke in others. Help get those exhibiting symptoms inside or into the shade ASAP. When heat waves strike, check in with other family members and friends who lack AC and have police perform a welfare check if they prove unreachable. When it comes to preventing heat-related illnesses and heat stroke, the cliche “better safe than sorry” applies.

Having Safe Fun in the Sun

How does heat stroke affect the brain? It claims many lives each year, but similar fatalities can be prevented through education and awareness. By knowing the signs of heat stroke, people can enjoy summer fun in the sun while keeping themselves and their families safe.