How to hydrate and other tips for Long Island's first heat wave of the year

The first heat wave of the summer is beginning and it’s not going away quickly. Temperatures are expected to top 90 degrees through Saturday and could soar to 99 and 98 on Thursday and Friday. Long Island health experts are urging people to stay indoors with air conditioning in the middle of the day — when the heat is at its worst — and have a bottle of water nearby at all times.

Here is what you need to know about beating the heat and staying hydrated.

How hot is it going to get?

AccuWeather is forecasting high temperatures of 91 for Wednesday, 99 on Thursday, 98 on Friday and 93 on Saturday for Long Island with lows dropping only to the mid- to high 70s. Parts of New York City could experience record-breaking heat with 100 degrees on Thursday and Friday. Even though a thunderstorm or two may pass through, they won’t bring much cooler air. In our region, three days above 90 degrees constitutes a heat wave.

What if I can’t stay inside all day?

Early mornings or late afternoon are the best times to get out, said Dr. Eric Decena, vice chairman of emergency medicine at Good Samaritan University Hospital in West Islip. If you have to be outdoors, wear sunblock and a hat, seek out shaded areas and drink plenty of fluids.

"Really try to limit your time outside in the middle of the day," Decena said. "This is especially important for elderly patients who are on medications for heart problems and other conditions. They can blunt your body’s mechanism to deal with the heat."

What are the signs of heat exhaustion and heatstroke?

Typically you'll feel very weak and some people can get nauseous," Decena said. Other symptoms include excessive sweating, dizziness and muscle cramps.

The body’s natural way of cooling is through sweating. If you are no longer able to sweat, that is a strong sign you are heading to heatstroke, he said. Another common symptom is mental confusion.

If you believe someone has heatstroke, call 911, remove them from the heat and try to cool them down with cold wet cloths or ice on their head, neck, armpits and groin, according to the Centers for Disease Control and Prevention.

How much water should I drink to stay hydrated?

It depends on factors including body size, age, activity level, and whether you are inside or outside, said Dr. Christopher Caspers, chair of the department of emergency medicine at NYU Langone Hospital-Long Island in Mineola.

"The rough rule of thumb is you want to make sure you're keeping up with as much as you're losing," he said.

Sotiria Everett, a registered dietitian and clinical associate professor at Stony Brook Medicine, said people who are pregnant and breastfeeding also need more fluids.

"A general rule is 0.5 oz. per pound but can be higher or lower depending on activity level and sweat loss," Everett told Newsday in an email.

What about sports drinks and energy drinks?

"Sports drinks aren’t necessary for most individuals, but those who work outside or exercise in the heat may benefit from them to replete electrolytes lost in their sweat," Everett said. "Water is best for most people."

She also pointed out that people who are on blood pressure medications need to watch their sodium intake and be careful around flavored drinks and sports beverages.

Caspers said energy drinks are a "wild card" because they could contain caffeine, vitamins, minerals and chemicals that could cause more fluid loss.

Can I drink beer to hydrate?

For some people, cracking open a cold beer on a hot day can sound like a good way to quench your thirst.

While most health experts won’t recommend it as a form of hydration — especially during a heat wave — they said you can drink alcohol in moderation as long as you drink water as well.

"Alcohol is always working against you and heat," said Caspers. "It's natural diuretic, meaning it's going to help your body lose water."

The hydrating properties of beer has been a hotly debated topic. A 2015 study out of Spain showed that having a regular beer had no poor effect on hydration after exercise in the heat.

Another study found that there was little difference between nonalcoholic beer, low-alcoholic beer and full-strength beer — in moderate amounts — and water or an isotonic sports drink when it came to fluid balance after exercise-induced dehydration.

By Lisa L. Colangelo

lisa.colangelo@newsday.com@lisalcolangelo

Lisa joined Newsday as a staff writer in 2019. She previously worked at amNewYork, the New York Daily News and the Asbury Park Press covering politics, government and general assignment.