Surviving the Heat: Recognizing Danger and Staying Safe

Millions of Americans faced heat advisories ahead of the July Fourth holiday. This occurred as a major heat wave spread across large parts of the central and eastern United States in early July 2026. For many people, this is the time of year for cookouts, beach trips, and other outdoor activities. Soccer fans were packing into stadiums for World Cup matches. However, summer also brings the risk of dangerously high temperatures and humidity in many parts of America.

In the United States, hundreds of people succumb to heat-related illnesses each year. Older adults and people in areas that historically have not needed air conditioning tend to see the highest rates of illnesses during heat waves. Chicago saw this clearly in 1995 when at least 700 people died in a heat wave. I study health risks in a warming climate as a professor of public health. I have seen heat become a growing concern. Here are some of the key warning signs to watch for when temperatures rise. I will also share ways to keep cool when the heat and humidity get too high.

Heat-related illnesses occur across a spectrum. Mild heat stress can quickly progress to life-threatening heat stroke if a person is exposed to dangerous conditions for too long. Mild forms of heat-related illness include heat cramps and heat rash. Both of these conditions can be caused by extensive sweating during hot conditions. Cooling the body and drinking cool fluids can help alleviate these symptoms.

When heat-related illnesses progress into heat exhaustion, the situation becomes more serious. Heat exhaustion includes symptoms such as dizziness, nausea, excessive sweating, feeling weak, thirst, and getting a headache. Heat exhaustion is a signal that the body is losing its ability to maintain a stable core temperature. Immediate action, such as moving to a cool, ideally air-conditioned space, drinking liquids, loosening clothes, and applying wet cloths, are some of the recommended steps. These actions can help keep heat exhaustion from progressing to the most dangerous form of heat-related illness, heat stroke.

Heat stroke is a medical emergency. At this point, the body can no longer maintain a stable core temperature. A body with heat stroke can reach 106 degrees Fahrenheit or higher rapidly. That intense heat can quickly damage the brain, heart, and kidneys. Typically, someone suffering from heat stroke has exhausted their reserves of sweat and salt needed to stay cool. As a result, sweating eventually stops during heat stroke. Their cognitive ability fails, and they cannot remove themselves from danger. Heat stroke can cause seizures or put someone into a coma as their core temperature rises. If the condition is not treated immediately, and the core temperature continues to rise, heat stroke becomes fatal.

Because heat exhaustion can lead to heat stroke, addressing heat-related illnesses before they progress is vital. You must monitor for signs of distress in yourself and others during extreme weather events.

Heat risk is not just about temperature. Humidity also increases the risk of heat-related illnesses. It affects how well sweating will cool the human body when it gets hot. Instead of just looking at temperature when planning outdoor activities, check the heat index. The heat index accounts for heat illness risk associated with both temperature and relative humidity.

It does not take very high temperatures or very high humidity for the heat index to enter dangerous territory. However, the heat index is still a conservative measure of the impact of heat on humans. This is particularly true for outdoor workers and athletes at summer practices. This conservatism exists because temperature measurements used in weather forecasting are taken in the shade. They are not exposed to direct sunlight. If someone is outside and exposed to direct sun, the actual heat index can be as much as 15 degrees Fahrenheit higher than the heat index chart indicates.

A more sophisticated measurement of heat effects on human health is what is known as the wet-bulb globe temperature. This measurement takes into account other variables, such as wind speed and cloud cover. Neither the heat index nor the wet-bulb globe temperature takes into account a person’s physical exertion. Physical exertion also raises body temperature, whether you are working at a construction site or playing soccer. Understanding these limitations helps you gauge the true risk of exposure.

How can you stay cool when heat waves set in? The answer depends in part on where you are. However, the main points are the same. First, avoid strenuous outdoor activities in high temperatures if possible. If you start to feel symptoms of heat-related illnesses, drink fluids that will hydrate you. Find shade, rest, and use cool, damp cloths to lower your body temperature. If you see signs of heat stroke in someone else, call for medical help immediately.

Be careful with fans. Fans can be useful if the temperature is not too high because they wick sweat away from the body. They induce evaporative cooling. But at very high temperatures, they can accelerate heat buildup in the body. This can lead to dangerous conditions. If indoor temperatures reach 95 degrees Fahrenheit or higher, using fans can actually be dangerous. It can raise the risk of heat-related illnesses rather than reduce them. In such cases, seeking alternative cooling methods is essential.

Find a cooling center, library, or community center where you can get inside. Rest in an air-conditioned space during the hottest hours. In places such as Phoenix, where high temperatures are a regular hazard, cooling centers are typically opened in summer. Northern cities are also opening cooling centers as heat waves occur there more frequently than they did in the past. This trend highlights the changing nature of climate risks across different regions.

Urban areas with a lot of pavement and buildings, known as heat islands, can have temperatures well above the city’s average. This phenomenon traps heat. It makes urban environments significantly hotter than surrounding rural areas. Being aware of local microclimates can help you plan safer routes and times for outdoor activities.

Hydrate, hydrate, hydrate! Drink plenty of fluids. Do not forget about the importance of electrolytes. Heat-related dehydration can occur when people sweat excessively. They lose water and necessary salts from the body. Some sports drinks or rehydration fluids restore electrolytes and hydration levels. Proper hydration is one of the most effective ways to prevent heat-related illnesses.

Older adults and people with disabilities often face higher risks from heat waves. This is particularly true if they cannot easily move to a cooler environment. Communities and neighbors can help protect vulnerable populations. They can provide cooling centers and bottled water. Making regular wellness checks during high heat is also crucial. Your community’s resilience depends on looking out for its most vulnerable members.

Summer can be a season of fun. Just remember the risks. Keep an eye on your friends and neighbors when temperatures rise. Plan ahead so you can beat the heat. Preparedness and awareness are your best defenses against the dangers of extreme heat.

This article was originally published June 19, 2025.