Prolonged exposure to stale heat and damp, choking humidity claims hundreds of lives each year, according to the Centers for Disease Control and Prevention.
The CDC reported a total of 7,233 heat-related deaths in the U.S. between the years of 1999-2009. In that time, an average of 658 people died of heat-related causes each year.
"A heat stroke is when a patient's temperature rises to 105 F, which can result in nausea, fever, confusion and loss of consciousness," Director of Integrative Pain Management at The Mount Sinai Hospital Houman Danesh, MD, said.
The human body's response to heat is dependent on three factors including activity level, humidity and temperature, Danesh said.
"The body under normal temperature variations will adjust to maintain the body's core temperature," he said. "A long day in the sun can lead to heat cramps, heat syncope (fainting), fatigue and heat stroke."
Victims of heat stroke may experience headache, dizziness, lack of sweating, muscle cramps, rapid heart rate and fainting.
Danesh said it is vital when experiencing any of the symptoms of heat stroke to seek medical attention immediately.
"If you suspect heat stroke, call 911 immediately," he said. "Delays in seeking medical care can be fatal. While waiting for an ambulance, place the patient in a cool, air-conditioned room, or shady area and remove unnecessary clothing."
If access to ice or water is available, Danesh said there are methods to cool a patient down.
"You can also fan the patient after wetting him or her or place (them) in an ice bath," he said. "If ice packs are available, apply to the groin, neck, armpits and back, as these (areas) are blood vessel rich."
Prolonged exposure to heat during a humid day as opposed to a dry one prevents the body from naturally cooling through sweat.
"The body cools down primarily by the evaporation of sweat on the skin," he said. "When the air is dry, sweat evaporates and cools the skin. When the air is humid, sweat doesn't evaporate as well and the body is unable to cool down."
To offset the stress caused by heat, staying hydrated is a key factor, along with wearing loose-fitting, light-colored clothing and protecting the skin with sunblock when outdoors.
Acclimating the body to warmer weather takes time, he added.
"Heat acclimatization is the process of increasing your body's core temperature so that the body sweat earlier and in greater qualities," Danesh said. "This allows the body to cool at lower temperatures and more effectively."
Older people living in hot apartments without air-conditioning are at the highest risk for heat stroke, he said.
In addition to older adults, young children and people with chronic medical conditions are also at high risk for heat-related deaths, the CDC reported.
"It takes about two weeks to acclimate with sun exposure of two hours each day," he said, adding that it is best to work out or be active in the heat a little longer each day, while keeping the body hydrated with an electrolyte rich drink every 15 minutes coupled with light meals.