Staying cool under high heat

Record high temperatures are being recorded across the country, leaving many at risk of experiencing heat-related illnesses. As families try to go about their typical summer activities, Dr. Maria Mejia, associate professor of family and community medicine at Baylor College of Medicine, shares how to spot symptoms of these illnesses and how to prevent serious health issues.

Dehydration

The first sign of most heat-related illnesses is dehydration. This occurs when your body loses more fluid than it takes in, preventing your body from functioning normally.

Common symptoms of dehydration differ by age:  

• Infants or young children:  
  o    Dry mouth and tongue  
  o    No tears when crying
  o    No wet diapers for three hours
  o    Sunken eyes, cheeks, a sunken soft spot on top of the skull
  o    Irritability
   
• Adults:  
  o    Extreme thirst  
  o    Less frequent urination  
  o    Dark-colored urine
  o    Fatigue  
  o    Dizziness
  o    Confusion

Many people, particularly older adults, don't feel thirsty until they're already dehydrated, Mejia said. “That's why it's important to increase water intake during hot weather or when you're ill.”

Repeated instances of dehydration can lead to long-term health issues such as urinary and kidney problems, seizures and hypovolemic shock. If a person does not properly hydrate in high-heat environments, they put themselves at a higher chance of experiencing heat exhaustion.

Heat Exhaustion

Heat exhaustion occurs when the body overheats and is unable to cool itself down. Common symptoms of heat exhaustion include increased sweating, rapid heart rate, low blood pressure and lightheadedness. If left unattended, symptoms can escalate to nausea, vomiting or diarrhea, causing accelerated dehydration, which makes it harder to treat heat exhaustion. In humid climates, people have a higher chance of experiencing heat exhaustion as high humidity slows or even stops sweat from evaporating off the skin.  

“At a certain threshold of heat and humidity, it’s no longer possible to sweat fast enough to prevent overheating,” Mejia said.

People who continue to stay in high temperatures after exhibiting symptoms of heat exhaustion run the risk of experiencing heat stroke.

Heat Stroke

Heat stroke occurs when a person’s core body temperature reaches 104 degrees Fahrenheit (40 degrees Celsius). During a heat stroke, the central nervous system becomes damaged and causes disorientation, confusion, behavioral or emotional changes or altered mental status. In serious cases, seizures or comas also can occur. Vital internal organs like the brain, liver and kidneys can be damaged by heat stroke.

If a person experiences a heat stroke, they must immediately seek medical attention.

Who is at risk

Although anyone can experience heat-related illness, certain populations are at an elevated risk.

“Those at greatest risk for heat-related illness include infants and children up to 4 years of age, people 65 years of age and older, people who are overweight and people who are ill or on certain medications,” Mejia said. "People working outdoors who are exposed to excessive amounts of heat, like welders or landscapers, are also at great risk.”

Mejia also said that exertional heat illness is one of the leading causes of death in young athletes each year.

Prevention

“The best way to prevent heat-related illness is to limit exposure outdoors during hot days, particularly from 11 a.m. to 3 p.m.,” Mejia said. “If you have air conditioning, the solution is simple — go inside or go to a cooling center such as a library or community center.”

Mejia also offers the following tips for caring for yourself and your community during high heat:

• Drink lots of water, even if you don’t feel thirsty, to ease the load on the heart, kidneys and other organs.
• Replace salt (electrolytes) lost from sweating by drinking fruit juice or sports drinks.
• If you must go outside, dress in loose, lightweight clothing and a hat and take breaks often.   
• Wear sunscreen, as sunburn affects the body's ability to cool itself.
• Check in on neighbors who are elderly, house-bound or otherwise may be reluctant to ask for help.
• Never leave kids or pets in a closed, parked vehicle.
• Stay alert to local heat advisories and identify your community’s cooling centers in case of an emergency.