Advance with MUSC Health

Here Comes the Sun: How to Handle South Carolina Heat Exhaustion

Advance With MUSC Health
June 22, 2022
Ryan Barnes, M.D.

The South Carolina summer heat is nothing to take lightly. The sun alone can be relentless for months on end, but pair that with the Lowcountry humidity factor, and it can mean double trouble. That’s why it’s important to know the symptoms of heat exhaustion and its more dangerous relative, heat stroke — and what to do if you find yourself experiencing them.

MUSC Health's Dr. Ryan Barnes is here to answer a few frequently asked questions on heat stroke and heat exhaustion.

What Are the Symptoms of Heat Related Illness?

Signs that you are suffering from heat exhaustion can occur suddenly or gradually over time. You're even more likely to experience symptoms after exercising for an extended period of time, particularly outdoors. Here are a few symptoms to be on the lookout for:

Heat Exhaustion

  • Heavy sweating
  • Faintness
  • Dizziness
  • Weak, rapid pulse
  • Headache
  • Muscle cramps
  • Nausea
  • Low blood pressure after standing up

Heat Stroke

  • Temperature greater than 104 F (40 C) and central nervous system abnormalities, including confusion, behavior changes, altered consciousness, seizure, and coma

What to Do if You're Experiencing Heat Exhaustion

  • Stop everything immediately and rest
  • Get out of the heat and into the shade or an air-conditioned space — a place where you can cool down.
  • Consume plenty of cool water or hydrating sports drinks
  • If symptoms don't improve within an hour, seek medical help.

If someone you know has experienced heat exhaustion and is confused, has lost consciousness, or is unable to drink anything, seek immediate medical help. Immediate cooling is necessary, particularly if your body temperature (measured by a rectal thermometer) reaches 104 F or higher.

What Causes Heat Related Illness?

Essentially, your body's failure to cool itself can cause heat exhaustion and stroke. Your body needs to maintain a core temperature of 98.6 F, so when it is unable to regulate the heat gain due to environmental factors, heat exhaustion is the result.

How Does Humidity Worsen the Risk of Heat Exhaustion?

Humidity is the amount of moisture in the air, which can make the temperature feel warmer because our sweat is slower to evaporate.

Sweating is the body's cooling mechanism. When your sweat can't evaporate, that causes a problem. When high humidity and sweat can't properly evaporate, your body cannot cool itself, making you more prone to heat exhaustion. Keep track of the heat index when you plan to spend time outside — if it's 91 F or higher, you need to take extra precautions to stay cool and avoid overheating.

How Can You Prevent Heat Related Illness?

Plan to spend time in the sun? Whether you're going for a jog or doing yard work, stay aware and know when to seek cooler temperatures. The three rules, according to the Center for Disease Control and Prevention, are


  1. Stay cool: Wear lightweight, light-colored, loose-fitting clothing. Exercise indoors if you can and limit all outdoor activity. Pace yourself. Protect your skin with sunscreen. Avoid hot and heavy metals — they add heat to your body.
  2. Stay hydrated. No matter how active you are, drink more fluids in the summertime. Drink sports drinks — sports drinks can replace the salt and minerals you lose when you sweat. Avoid sugary drinks and alcohol — they can cause you to lose more body fluid.
  3. Stay informed. Watch the heat index. Check for heat advisories. Monitor those around you who are high risk, like children, seniors, dogs, people who overexert during exercise, and anyone who's physically ill, particularly with heart disease or high blood pressure.

If you think you're at high risk of heat exhaustion or recognize these symptoms from experience, talk to your primary care doctor soon to discuss your unique situation and what more you can do to prepare for and prevent heat exhaustion.