Heat Exhaustion vs. Heat Stroke While Driving: What to Do

By The Standard Carry Co Field Team · Last updated June 2026

Heat exhaustion and heat stroke are heat illnesses on a severity spectrum, and on a long, hot drive it helps to know which is which. Heat exhaustion is the warning: sweating, weakness, dizziness, nausea. Heat stroke is the emergency: a very high body temperature, confusion, and a change in behavior. The short version is simple. If you suspect heat stroke, call 911 immediately and start cooling the person.

Emergency note: heat stroke is a life-threatening medical emergency and delay can be fatal (National Weather Service). Call 911 right away for confusion, slurred speech, fainting, or a very high temperature. This page is general safety information, not medical advice.

Heat exhaustion: the warning stage

Common signs (CDC, National Weather Service):

Heavy sweating
Cold, pale, or clammy skin
Weakness or tiredness, dizziness, headache
Nausea or vomiting
A fast, weak pulse and muscle cramps

What to do: pull over safely, get to shade or a cooler place, loosen clothing, sip water if you are fully alert and not vomiting, and cool down with a wet cloth, airflow, or a cooling towel. Rest until you genuinely feel better. If symptoms worsen, last more than about an hour, or you start vomiting, seek medical help.

Heat stroke: the emergency

Signs that it has crossed into an emergency (CDC, National Weather Service):

A very high body temperature
Hot, red skin that may be dry or damp
Confusion, slurred speech, or a change in behavior
Loss of consciousness
A fast, strong pulse

What to do: call 911 immediately. Move the person to a cooler place, help lower their temperature with cool water and air, and do not give fluids to someone who is confused or not fully alert. Heat stroke is a medical emergency; getting help fast matters most.

Why driving makes it riskier

A vehicle interior runs far hotter than the outside air, and the early signs of heat illness, dizziness and trouble concentrating, are also a driving hazard. If you feel any of them, treat getting safely off the road as the first step. Higher-risk drivers, including older adults and anyone with health conditions, should be especially cautious in extreme heat. For roadside steps, see stranded in a hot car, what to do.

Staying ahead of it

No gear prevents heat illness, but water, shade, and cooling help you stay ahead of it and respond when it starts. Carry shelf-stable water and electrolytes, keep a cooling towel and sun protection in the cabin, and use a windshield shade and shade parking to keep the cabin cooler. See what belongs in a summer car emergency kit and cooling gear that actually works.

FAQ

What is the difference between heat exhaustion and heat stroke?

Heat exhaustion is the warning stage: heavy sweating, cold or clammy pale skin, weakness, dizziness, headache, nausea, and a fast, weak pulse. Heat stroke is a life-threatening emergency: a very high body temperature; hot, red skin that may be dry or damp; confusion or slurred speech; loss of consciousness; and a fast, strong pulse. Heat stroke is a medical emergency. Call 911 immediately. This is general information, not medical advice.

What do I do if I feel heat exhaustion while driving?

Pull over safely as soon as you can, get to a cooler place or shade, loosen clothing, sip water if you are fully alert and not vomiting, and cool down with a wet cloth or fan. Do not keep driving through dizziness or confusion. If symptoms worsen or last more than about an hour, or if any sign of heat stroke appears, call 911.

When is heat illness a 911 emergency?

Call 911 right away for any sign of heat stroke: confusion, slurred speech, fainting or unresponsiveness, a very high temperature, or hot skin with a change in behavior. Heat stroke can be fatal and delay is dangerous (National Weather Service). While waiting for help, move the person to a cooler place and cool them with water and air.

Can a car emergency kit prevent heat stroke?

No. No kit prevents heat illness. Water, shade, and cooling help you stay ahead of it and respond when it starts, but prevention is about heat exposure, hydration, rest, and getting out of the heat. If heat stroke is developing, the answer is to cool the person and call 911, not to rely on gear.

Sources

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