Here’s a new fact about spring, summer, fall and sometimes even winter, now that climate change has blurred the lines between seasons: blistering heat could be on the way or already engulfing your community.
High temperatures take a toll on the body, leading to thousands of heat-related illnesses and deaths in the U.S. each year. Creating a personal heat plan can help you stay safe when the heat index skyrockets.
Caleb Dresser, MD, MPH, is the director of health solutions at C-CHANGE, the Center for Climate Health and the Global Environment at the Harvard T.H. Chan School of Public Health, and an emergency medicine physician at Harvard-affiliated Beth Israel Deaconess Medical Center. Below, we interview him about who, how and why heat harms. Then, we’ll help you create your own personal heat safety plan.
Interview edited for clarity
Who is most at risk in hot weather?
High temperatures can affect anyone. However, some people — children, people who work outdoors, are pregnant or have health problems or disabilities, and the elderly — are more vulnerable to harm when temperatures rise. For example:
Young children, especially babies, are less physically able to handle very high temperatures.
People who work outdoors may not have access to shade and may perform physically demanding work. They need to stay hydrated, take adequate breaks, and have access to a cool room during breaks, as required by OSHA guidelines.
People with chronic conditions such as kidney or heart disease may have difficulty adjusting physiologically to hot weather or may be more vulnerable to its health effects.
And some people with disabilities or certain neurological conditions may have trouble thermoregulating — that is, controlling their body temperature — or may be unable to take steps to keep themselves safe, such as removing multiple layers of clothing or staying in a cool area.
What weather patterns produce dangerous levels of heat?
Dangerous heat is the result of both high temperatures and high humidity, which impair our ability to cool ourselves by sweating. In dry areas, extremely high temperatures can be dangerous in and of themselves.
Danger zones vary across the United States and around the world. But hospital use and deaths increase once we cross the threshold temperature. The threshold varies in different places, depending on whether bodies, cultures, and architecture are adapted to heat.
Here in New England, for example, where some people (especially those with limited means) may not have access to air conditioning, we see increases in healthcare use and deaths at lower temperatures than in the American South, where people and organizations are more accustomed to hot weather.
At what point does hot weather become dangerous to our health?
The risk increases the longer hot weather persists.
One hot day can put some people at risk. Several hot days in a row during a heat wave are especially dangerous because they can overwhelm people’s ability to adapt. Eventually, people run out of physiological reserves, resulting in greater health damage and a greater need for medical care.
Surprisingly, spring and early summer are particularly dangerous times because people and organizations are not as well prepared for hot weather.
How to create your personal heat protection plan
Below are five key points to help you create a personal heat plan. Americares offers more information in the form of heat tip sheets developed with the Harvard C-CHANGE team and tailored to people with different health conditions.
Planning is important because intense heat is becoming more common: A Climate Central analysis found an average of 21 additional risky heat days in 232 of 249 locations between 1970 and 2022.
Get ahead of the hot weather. Check apps, websites, TV or radio for the weather today and in the days ahead. If local weather alerts are available by phone or text, sign up.
Have a cooling plan. When temperatures rise, you need to spend as much time as possible in cool spaces. Plan options in case your home is likely to be too hot and unsafe to stay in. Maybe you can stay with a neighbor or family member with air conditioning until a heat wave passes. Many cities and towns have neighborhood wading pools for children and open cooling centers or air-conditioned libraries, public buildings or community centers for everyone — sometimes even overnight. Staying in air-conditioned stores or malls or in shaded green spaces like parks can also help.
Drink plenty of fluids. Water is the best choice. Avoid sugary drinks and avoid caffeine or alcohol.
Use fans properly. Fans help when the surrounding air is relatively cool. When air temperatures are very high, it’s important to moisten your clothes or skin to prevent your body from overheating and move to a cooler location if possible.
Know your personal risks and the signs of heat-related illness. If you have health problems or disabilities or are taking certain medications, such as diuretics, talk to your doctor about how best to cope with the heat. It’s also important to know the signs of heat-related illness, which range from heat rash and sunburn to heat cramps, heat exhaustion and heat stroke. This chart from the Centers for Disease Control and Prevention describes what signs to look for and what to do, especially if heat becomes an emergency.
