Summer Crowds Health Risks: ER Doctors' Prevention Tips

From World Cup matches to stadium concerts, summertime brings plenty of events that combine big crowds with high temperatures.

“While we’re out there having fun, our bodies are working overtime just to keep us cool,” says Columbia emergency medicine physician Erica L. Olsen, MD, who notes that factors like unpredictable crowds, alcohol consumption, and infectious disease spread can combine to create health risks.

There are also several concerns specific to children, says pediatric emergency medicine physician Son H. McLaren, MD—from sensitive hearing to the possibility of getting lost.

Drs. McLaren and Olsen flag the top risks of summer crowds and share ways to enjoy your favorite events while staying out of the ER.

What are the top health risks of attending crowded summer events?

“The most common are heat-related conditions, such as heat syncope or near syncope (fainting or almost fainting), which involves lightheadedness that can occur after standing for long periods in the heat,” says Dr. McLaren. Other heat-related illnesses include heat exhaustion (a more serious condition that elevates core body temperature) and heatstroke (a medical emergency where core body temperature rises above 104 F).

“Crowd density blocks airflow and traps heat, directly increasing the risk of heat-related illness,” says Dr. Olsen. “And crowds make it harder to recognize and reach someone who is in trouble—everyone is distracted, it’s loud, and warning signs can easily go unnoticed.”

Other potential issues include dehydration and infectious disease risk. “Add alcohol into the mix of heat and crowding, and we’re compounding fluid loss while also impairing our ability to take care of ourselves,” says Dr. Olsen. “And the close contact between many people and touching lots of shared surfaces can allow some infectious diseases to take hold.”

Heat exposure and dehydration can also worsen underlying medical conditions, notes Dr. McLaren. “With asthma, for example, exposure to smoke, air pollution, or extreme heat can lead to exacerbations.” What’s more, medication side effects can be worsened by heat. “The same side effects that are typically not a big deal can, on a hot day, increase the risk of heat-related illnesses.”

Additional concerns include the impact of loud sounds on hearing and the possibility of dangerous crowd surges.

What are the best ways to prevent health problems in summer crowds?

In addition to the usual precautions—like applying sunscreen correctly and choosing the right sunglasses—the following tips will help avoid health emergencies at crowded events:

• Dress to protect: Wear a hat and loose-fitting clothing to increase airflow and heat loss. Also, wear closed-toe shoes to protect your toes from being stepped on.
• Hydrate: Drink water and check with your doctor before the event to see if you should also have electrolyte drinks, says Dr. Olsen. “With prolonged sweating, we need electrolyte replenishment, but some medical conditions, like kidney disease, and medications make these drinks inadvisable.” In addition, choose (or bring) snacks with high water content, like watermelon and cucumber. When it comes to beverages, “Remember that alcohol is a diuretic. Drinking alcohol in excessive heat increases the probability of serious dehydration,” says Dr. Olsen.
• Spot signs of heat-related illnesses: If you feel lightheaded or weak, quickly find a safe, cool place to sit or lie down. Hydrate with cool beverages, ideally electrolyte-supplemented beverages such as sports drinks. If symptoms persist or worsen to include nausea, vomiting, headache, or confusion, seek medical care.
• Locate event health services: Note the locations of AEDs and health services. “If you know that you are predisposed to having a problem, situate yourself near an exit and don’t go deep into the crowd. Carry a cellphone to call for help, if necessary,” says Dr. Olsen.
• Consider chronic conditions and medications: Before the event, talk to your doctor or pharmacist to understand any risks, and pack medical supplies, such as inhalers and EpiPens. “While at the event, avoid circumstances or triggers that may exacerbate a chronic condition. For food allergies, communicate clearly with food vendors to reduce accidental exposures,” advises Dr. McLaren.
• Know crowd safety strategies: Have a plan in case a crowd becomes unpredictable. In addition to locating exits, avoid standing near barricades and fences, where a crowd surge could lead to crushing. And never go against a moving crowd—instead move sideways or diagonally.
• Block germs without going overboard: “In general, good hand hygiene is an effective way to prevent common viral infections: Use hand sanitizers or wash hands with soap and water frequently, including before eating,” says Dr. McLaren. For most families, routine masking is not necessary. However, if you are traveling to areas with known outbreaks, or if you are immunocompromised or have underlying health problems, talk with your doctor or check the Centers for Disease Control and Prevention’s Travelers’ Health advisory for recommendations.

What are the best ways to keep kids safe in summer crowds?

While many adult safety strategies apply to all ages, young children may benefit from additional considerations, such as:

• Stay on top of hydration: While most adults can “drink to thirst,” young children need regular reminders. Water is best, as opposed to juice and soda, which have too much sugar and too little sodium. “If the event venue allows, bring insulated water bottles,” says Dr. McLaren. “And if a child will be engaging in strenuous activities for more than one hour, hydrate with electrolyte-supplemented beverages.”
• Win the sunscreen battle: Many children resist greasy, cream-based products. “Sunscreen sticks can be a better approach,” says Dr. McLaren. Apply sunscreen at least 15 minutes before going outdoors (so it has time to be absorbed), then apply liberally and frequently (at least every two hours).
• Protect young ears: While everyone should beware of high noise levels, young children are particularly vulnerable to the impact of loud sounds on hearing. “Children with autism may also have increased sensitivity to excessive environmental noise,” notes Dr. McLaren. The American Academy of Pediatrics recommends using hearing protection at events where noise levels can damage hearing (generally at or above 85 dBA). “Find a hearing protector with a high noise reduction rating that your child likes enough to wear,” adds Dr. McLaren.
• Prevent getting lost: Before the event, have your children memorize your name and phone number, or put a card with contact information in their clothes. In crowded areas, hold hands or have your child walk in your sight line. If your child becomes separated from you, they should stay in place and listen for your voice (most likely, you are steps away). “And make sure they can identify a safe adult to ask for help, such as a police officer, security guard, event staff member, or a parent with children,” adds Dr. McLaren.

Son H. McLaren, MD, is an associate professor of pediatrics (in emergency medicine) at the Columbia University Vagelos College of Physicians and Surgeons.

Erica L. Olsen, MD, is an assistant professor of emergency medicine at the Columbia University Vagelos College of Physicians and Surgeons.