Sweltering heat can be downright dangerous for your health, especially for your heart. Even if you love hot weather, anyone can be at risk for heat illnesses when temperatures spike.
The National Weather Service generally starts issuing heat advisories when the heat index is expected to reach 100° or higher for at least two days. That's a good time to start preparing for potentially dangerous or deadly heat conditions.
“Whenever there's excess heat, the body has to have a way to compensate for that," says Ankit Bhatia, MD, with The Christ Hospital Physicians – Heart & Vascular. “The way the body cools itself down is by sweating with evaporation on the skin itself."
The body also cools itself by diverting blood flow to the skin. As the body loses fluids to sweat, the organs get a reduced supply of blood and oxygen they need to function properly. At the most extreme, this can lead to heat exhaustion and heat stroke.
“Cardiovascular patients are much more prone to heat stroke because they can't compensate well to begin with," Dr. Bhatia says. “Many of our patients with heart disease are on blood pressure medications and diuretics that make them more prone to dehydration, lower blood pressure, and consequences of excess heat."
Warning signs for heat exhaustion and heat stroke
Being outdoors in hot weather is sometimes unavoidable. Some workers have outdoor jobs. Younger athletes may have outdoor practices. Then there are outdoor events we don't want to miss, like music festivals, county fairs, block parties, or a day at the ballpark.
Dr. Bhatia explains there are two major causes of heat-related illnesses:
Exertional heat illnesses are tied to significant physical activity in high temperatures. Anyone can be at risk of overdoing it in the heat, even trained athletes in peak physical condition.
Non-Exertional heat illnesses are connected to simply being in hot conditions and not being able to compensate for the heat. These heat illnesses tend to affect infants and young children, senior adults, and people with chronic medical conditions like heart disease.
The mildest stages of heat illness can cause symptoms like muscle cramps or swelling. This can quickly progress to heat exhaustion if steps aren't taken to cool down.
Heat exhaustion is serious because the body can no longer keep itself cool. People with heat exhaustion may show signs of:
- Heavy sweating
- Dizziness or lightheadedness
- Elevated body temperature
- Cold, clammy skin.
“If you're starting to notice that someone is really not themselves and not responding the way they should, that is someone who needs to be cooled down and given hydration immediately," Dr. Bhatia says.
Heat stroke is the most extreme form of heat illness and is a true medical emergency. “At the end stage of heat stroke, you're not getting enough blood flow to your brain and can become disoriented and altered," Dr. Bhatia says. “These symtoms need to be taken very seriously."
Symptoms of heat stroke can include:
- Body temperature spiking to 104°F or higher
- Loss of consciousness
- Confusion or slurred speech
- Hot, dry skin or profuse sweating
Heat stroke can be fatal. The Centers for Disease Control and Prevention recommends calling 911 for medical aid. You should also get someone experiencing heat stroke to a cooler area or into the shade immediately.
“In the hospital if someone comes in with heat stroke, there are multiple approaches for cooling, including putting fluid all over the patient's body and start fans to evaporate the fluid off of them," Dr. Bhatia says. “There are multiple other internal and external cooling approaches that can be used as well."
Prevention is key to avoiding heat illnesses
Heat illnesses can be avoided with proper planning for dealing with extreme heat.
Get proper hydration: “Hydration is key for allowing any person to compensate for heat and tolerate it much better," Dr. Bhatia says. “You really need to drink water or some other electrolyte solution [like a sports drink]." It's also best to avoid caffeine and alcohol because they can contribute to dehydration.
Take frequent breaks: Find some shade or air conditioning, especially if you feel overheated. “Make sure you're resting until you feel back to your normal self," Dr. Bhatia recommends.
“Choose the times of day when you're active and avoid peak sun," Dr. Bhatia continues. “When the sun is at its highest temperature, people are going to lose the most fluid out of their body and sweat more excessively."
Dress for the weather: Pick breathable fabrics like cotton and linens.
Watch out for each other: Look for signs that others may be struggling in the heat or not behaving normally. “Altered behavior or mental status can be a sign of heat stroke due to inadequate blood flow to brain," Dr. Bhatia says.
Understand your medications: Certain medications like beta blockers, diuretics, ACE inhibitors, and calcium channel blockers can contribute to dehydration and predispose you to heat-related illness.
“They lower the overall amount of fluid in your body, so you are less able to sweat out excess fluid to cool yourself," Dr. Bhatia says. “It makes you more prone to succumbing to extreme heat because you can't compensate."
Travelling to hotter climates: Snowbirds wintering in warmer states or simply traveling to an area experiencing extreme heat can also up the risk for heat illnesses, especially for people with cardiovascular disease.
“Say you've got a patient on a diuretic or blood pressure medication that they've been able to tolerate fine in Cincinnati," Dr. Bhatia explains. “They go hiking in Seguaro National Park in Arizona and all of a sudden their meds become more potent because they're losing so much more fluid than they normally would."
“It's really important to keep in mind adequate hydration and talking to your doctor to ensure your meds are going to be appropriate for a change in lifestyle and environment," Dr. Bhatia says.