NYC Heat Wave: Doctors Warn Everyone To Be On Alert For Heat Exhaustion

At-A-Glance

• Con Edison Under Pressure To Keep Power On
• NYC Triathlon Canceled For First Time In Its History
• New York City Cooling Centers Open
• Summer Heat Survival Guide

NEW YORK (CBSNewYork) -- Temperatures are soaring to dangerous numbers across the country.

Doctors are warning people to take precautions in these sweltering conditions, CBSN New York's Cindy Hsu reports.

Mayor Bill de Blasio has issued a heat emergency across the city, as the high heat and humidity come with health risks like heat exhaustion or heat stroke.

Web Extra: Doctor Shares Life-Saving Tips On Surviving The Dangerous Heat --

Dr. Ernest Patti is a tending emergency room physician at St. Barnabas Hospital.

"We see the myriad of symptoms that are related to heat-related illness. People come in feeling fatigued, dry, dehydrated, weak. Some of them come in with nausea and vomiting, and basically just washed out from the heat and the humidity," Patti said. "And it can progress, especially if the symptoms are not treated appropriately or recognized by the patients and/or those around them."

Dr. Baruch Fertel, an emergency room doctor at the Cleveland Clinic, says heat exhaustion happens when there isn't enough fluid in the body.

Symptoms of heat exhaustion include, Fertel says, "cramping, the body is warm to the touch, decreased sweating, some dizziness, some nausea, not feeling right."

Patti says the humidity is a "really big factor" in the danger of the heat wave.

"The way the body cools itself, it has a number of mechanisms, but one of the most effective ones is by evaporating sweat off of your body. So you perspire and that sweat evaporates and it cools the body's temperature down. As the humidity rises, it's really harder for that mechanism to work. Because the air is full of moisture, it's harder to evaporate," Patti said. "So that mechanism starts to fail, and if you continue to do your activities and your exercises without paying attention to that, you'll eventually get into the heat-related disorders and eventually, you know, get really sick."

Fertel cautions if you're not careful, heat exhaustion can progress to heat stroke, which is a life-threatening medical emergency. Warning signs include a temperature of 103 degrees or higher, a throbbing headache, confusion and an altered state.

RELATED STORY: Ex-Giants Offensive Lineman Mitch Petrus Dies Of Heat Stroke

Staying hydrated is key.

"It's important that we use liquids that are hydrating. So for example, salt-containing liquids or drinking water with meals that have salt in them, very important to help retain some of that fluid in our body. Sports drinks that have electrolytes can be very helpful, and things we really want to avoid would be alcohol, caffeine beverages," Fertel said.

On these hot days, don't just drink when you are thirsty. If you're thirsty, that could be a sign you're already getting dehydrated.

"If you not sweating or if you're not peeing, it means you're probably starting to fall behind," Fertel said.

Wearing light, loose clothing can also help on these hot days, and doctors say try to take breaks from the heat.

"You should limit those hours outdoors. You should also bring some shade. Bring an umbrella with you. Even if you're normally not one to sit under the umbrella, it's a really good idea to have it. Give your body a little bit of a rest because in the direct sunlight, your core temperature's gonna go up, you're gonna need to replenish your fluids and you're gonna need to definitely keep an eye on how your body's reacting," Patti said.

Patti says if you need to go outside this weekend, try to get out early in the morning or later in the evening when the sun is at its lowest points. He also says not to exercise or exert yourself outside, and try to stay indoors in air-conditioned areas, like movie theaters, malls or public libraries.

Young children, the elderly and people with chronic medical conditions are the most vulnerable to heat illnesses, and they should never be left in vehicles.

"Please, please, please never even consider leaving a pet or a child in a car because the temperatures in cars go up within seconds in a heat-related weekend like we're going to experience. People can die immediately in a hot car with closed windows," Patti said.

Taking care in the heat doesn't just apply to people. Pets also need access to plenty of water and should come inside often because everyone needs to stay hydrated and cool.