Headed to an outdoor concert or event? How to stay safe in the heat.

With many outdoor festivities and concerts underway — including Chicago’s four-day festival Lollapalooza, which begins Thursday — it’s important to know how to protect yourself and how people may experience extreme heat during outside events.

What makes these events a risk in the heat

Concertgoers and festival attendees expose themselves to multiple heat-related risks, which could lead to issues as minor as heat cramps to more severe situations like heat stroke, which can be fatal. Although the deaths are often preventable, extreme heat is the No. 1 weather-related killer in the United States, according to federal data.

In June, nearly a dozen people were hospitalized at an Arizona outdoor rally for former president Donald Trump where temperatures exceeded triple digits. In July 2023, over a dozen concertgoers and workers were hospitalized for heat-related illnesses at an Ed Sheeran concert performed at an outdoor venue in Pittsburgh. In November, a fan died after a Taylor Swift concert in Brazil during a scorching heat wave.

Neil Gandhi, an emergency medicine physician in Houston Methodist Hospital’s emergency department, said that it would be more advantageous to start planning musical festivals and concerts during seasons when temperatures are cooler.

“It would reduce or de-risk the chance of any kind of heat-related illness from happening,” Gandhi said.

Potential for dehydration

The most important and controllable risk is dehydration, said Richard Doyle, a health system clinician of emergency medicine at Northwestern University’s Feinberg School of Medicine.

During extreme temperatures, the body needs more liquids than normal to account for increased sweating. Once your body starts losing more fluids than you’re consuming, that’s when trouble can arise. Risk of dehydration can be exacerbated by increased activity — like dancing and walking, Gandhi said.

It’s important to know some symptoms of heat illness to protect yourself. If your muscles become tight or sore after prolonged heat exposure, you could be suffering from heat cramps, Gandhi said. Profuse sweating, nausea, rapid heart rate and headache are symptoms of heat exhaustion.

Experts urge concertgoers to drink enough fluids.

What you drink may add to the risk

Drinking a cool alcoholic beverage while the thumping bass moves the crowd may seem like the perfect combination at a concert — but it can add to the dehydration risk.

Alcohol opens the blood vessels in your skin, allowing the blood to be more susceptible to external temperatures. As the blood rushes to the surface, it is pulled away from your core, where it is warmed by the outside temperatures. Once the blood is warmed and brought back to the core, your overall body temperature increases.

“If you’re consuming any alcohol, make sure you break it up with a sufficient amount of water before, during and after drinking,” Gandhi said. Alcohol can also impair your ability to recognize the impacts of high temperatures and how long you’ve been exposed.

Alcohol is a diuretic, which leads to increased urination and potential dehydration.

Drinks with high levels of caffeine are also considered diuretics, which can dehydrate the body through increased urination.

Be careful with large crowds and long days

Packed crowds can create heat and limit people’s ability to find shade and hydrate. Overcrowding during extreme temperatures can trap heat, said Geoffrey Comp, an emergency medicine physician at Valleywise Health Medical Center in Phoenix.

Temperatures can quickly rise in the crowd “especially if everyone is dancing and generating heat as well as the ambient increased temperatures,” he said.

When temperatures reach scorching levels, most people tend to find cool environments to weather the heat. But concerts and festivals encourage people to spend prolonged periods of time outdoors.

With little shade and no access to air conditioning, long hours — or even long days — can be dangerous.

What can you do to keep cool?

Hydrate. It’s important for everyone to hydrate during extreme temperatures — especially with increased activity and prolonged exposure. “People should be excited about the event but also have a plan to keep hydrated and identify locations to get out of the sun if they are feeling too hot,” Comp said.

Bear in mind that the high costs for water and other cool drinks at venues can put people at risk of overheating and dehydration, Comp said.

Find shade. An awning, a roof or a spot blocked from direct sunlight can provide some relief from the heat, Gandhi said.

“When you have significant amounts of sunlight onto your skin, you can literally start to just dehydrate away from the inside slowly,” Gandhi said.

Comp said that mild forms of heat illness like heat cramps or even heat exhaustion can be treated by cooling and getting out of the heat.

Wear the proper clothing. Experts suggest wearing loosefitting clothing because tighter outfits can force sweat to stick to your body, making you overheat more quickly. Tight clothing can also impair your ability to sweat normally, Gandhi said.

Wide-brimmed hats can decrease direct sun exposure on your neck and face.

Acclimatize. If you’re going to a concert or festival out of town or aren’t used to staying outside for extended periods, unfamiliar environmental conditions could become a risk factor.

Experts suggest trying to acclimatize your body for days or weeks ahead of time by spending more time outdoors.

“You’ll become a little bit more acclimated to what the environmental conditions will be for the three or four days of the festival,” Gandhi said.