How to Beat Heat Illness and Stay Healthy This Summer

With an average high temperature of 82 F, July is the hottest month of the year in Massachusetts. 

But even before July arrived, much of the state had already experienced record-breaking heat during a sweltering four-day heat wave in the final week of June. 

If it seems like heat waves are happening more often, are more intense and longer lasting – it’s because they are.  

Climate change is fueling the increase in extreme heat events and their intensity, scientists say. Greenhouse gas emissions trap heat in the atmosphere making it harder for the Earth to cool at night, leading to more frequent and longer-duration heat waves. 

According to the Environmental Protection Agency (EPA), the number of heat waves in major U.S. cities annually has tripled in the last half century; increasing from two per year in the 1960s, to six per year during the 2010s and 2020s.  

And it has been hazardous to our health.

Extreme heat is the leading weather-related cause of death in the U.S., and kills more than 700 people each year, according to the Centers for Disease Control and Prevention (CDC).  

“Heat is very dangerous,” said Todd Ellerin, MD, Director of Infectious Disease and Vice Chair of Medicine at South Shore Health. “Extreme heat is invisible, and you can underestimate it.” 

Young children, pregnant woman, older adults and those with chronic medical conditions like lung, heart or kidney disease are at the greatest risk for heat-related illnesses.

“These are parts of the body that the heat really stresses,” said Ellerin.

Outdoor workers and those who can’t get inside and away from the heat, including people who are housing insecure, are also at high risk in extreme heat.

And it’s not just about the heat, Ellerin said.

“When high heat is combined with high humidity, it adds up to an even higher heat index or ‘feels like’ temperature, which makes it a double whammy.”

That’s because when temperatures reach the 90s (or higher) and dew points are in the 70s, the body’s cooling mechanism begins to fail.  

“The way our body deals with heat is by sweating,” Ellerin said. “When there is a lot of water vapor in the atmosphere, it can shut down your ability to sweat, causing you to overheat much faster and putting you at risk for heat exhaustion and heat stroke.”

The CDC describes heat exhaustion as the body’s response to an excessive loss of water and salt through excessive sweating. 

Signs of heat exhaustion include:

• Headache
• Nausea
• Dizziness
• Rapid breathing
• Weakness
• Muscle cramps
• Heavy sweating
• Elevated body temperature
• Decreased urine output  

Heat stroke, the most serious heat-related illness occurs when the body can no longer control its temperature; sweating fails, the body’s temperature rapidly rises (to 106 degrees or higher) and cannot cool down. Heat stroke can be fatal without emergency treatment.

Symptoms of heat stroke include: 

• Confusion, altered mental status, slurred speech
• Hot, dry skin or profuse sweating
• Very high body temperature
• Seizures
• Loss of consciousness (coma)

It’s important to recognize the symptoms of heat illness and seek medical help right away if you, or someone you know is experiencing them.

It’s also crucial to know your own risk, Ellerin said. People on certain medications are more susceptible to heat-related illness. 

High blood pressure medications such as diuretics can make you more dehydrated and beta blockers, which affect blood flow, can make it more difficult to evaporate heat. 

Anti-depressants and anti-psychotic medications work on the hypothalamus, the part of the body that regulates temperature, which can make it much more difficult to deal with extreme heat.

Ellerin advises taking a proactive approach to stay safe when the heat index soars again this summer. He recommends following the tips in the acronym, S-H-A-D-E. 

• “S” stands for Stay hydrated by drinking lots of water and other non-alcoholic liquids.
• “H” stands for Heat awareness. Know what the heat index/feels like temperature is before planning outdoor activities. 
• “A” stands for Air conditioning and fans. Get inside where air conditioning is available. Bring portable/handheld fans to keep cool at outdoor events.
• “D” stands for Drop strenuous activities. Exercising outside when the heat index is over 100 degrees and your body can’t sweat is a recipe for disaster.
• “E” stands for Emergency planning. If you don’t have access to air conditioning, know where the nearest cooling center is and find other extreme heat resources from your local board of health or the Massachusetts Department of Public Health website. 

Extreme weather events, as we have just seen in central Texas, can be sudden and deadly, Ellerin said.  

"Flash flooding, hurricanes, tornadoes, blizzards are visible threats that we can avoid by staying inside or evacuating to safety, if given enough warning.  Extreme heat is an invisible threat we need to take seriously. Be prepared for the next heat wave by seeking S-H-A-D-E."

Todd B. Ellerin, MD is Director of Infectious Disease and Vice Chair of Medicine at South Shore Health.