Dear Doctors: Can you explain heat exhaustion and heat stroke?
Answer: Even on what feels like a mild day, missteps having to do with clothing, terrain, hydration and your level of exertion can turn the sunny weather that drew you outside into a serious health threat.
Heat-related illnesses fall into three categories — heat cramps, heat exhaustion and heat stroke.
The mildest is heat cramps, though, when you’re experiencing them, “mild” won’t be the word that comes to mind. They are painful, involuntary muscle contractions in the calves, thighs, arms or abdomen.
Heat cramps are associated with heavy sweating and can occur during intense physical activity or if you’re exercising beyond your level of conditioning.
Someone with heat cramps should move to a shady spot and drink water or a sports drink. Don’t resume activity until the cramps have subsided.
The next step on the heat illness continuum is heat exhaustion. Symptoms include heavy sweating, a rapid pulse that also might be weak or irregular, muscle cramps, nausea or vomiting, headache, dizziness, cold or clammy skin, feeling weak and feeling confused.
Unless addressed promptly, heat exhaustion can progress to heat stroke, which is a life-threatening emergency. Someone with heat exhaustion should immediately move to a cooler spot and loosen clothing to allow air circulation. Use damp cloths to cool the skin or immerse yourself — including the face and scalp — in cool water. Sip water gradually. Drinking too much can lead to cramps or vomiting.
Someone with heat stroke is at risk of dying. Symptoms include hot skin, a rapid, pounding pulse, nausea or dizziness, headache, shallow breathing, confusion or delirium and a temperature of 103 or higher.
Unlike someone with heat exhaustion, people with heat stroke will not sweat. Get them to a cool or shady spot, cool their body with water, and get them immediate medical care.
To avoid heat-related illness, choose activities appropriate for the weather. Wear loose, light clothing. Carry plenty of water, and drink it in moderation — you don’t want to over-drink. Rest in the heat of the day. Wear a hat and sunglasses. Use salty snacks or sports drinks to help replace lost electrolytes. And never ignore the signs of heat illness.
Dr. Eve Glazier and Dr. Elizabeth Ko are internists at UCLA Health.