As Long Island braces for the potential first heat wave of the season, doctors are warning that extreme heat and dangerous UV levels could quickly put people at risk for sun damage and heat-related illness.

Families flocked to local pools this week to cool off, but with the UV index expected to reach 9, health experts say protection from the sun is essential.

“I put sunscreen on before I came to the pool today because I don’t want to get burned,” one poolgoer said.

Another added, “Sunscreen is like the best.”

Good Samaritan Hospital physician Dr. Eric Decena said sunscreen is one of the most important tools for preventing both immediate and long-term skin damage. He recommends applying sunscreen before going outside and reapplying every two hours, or sooner after swimming or sweating.

“The long-term damage of skin, you’re not going to see immediately,” Decena said. “You’ll get sunburn initially, but over time, that can make you more prone to skin cancers and things like that in the future.”

Doctors say staying safe in the heat goes beyond preventing sunburn. Finding air conditioning, staying hydrated and limiting time in direct sunlight can help reduce the risk of heat exhaustion and heat stroke.

Decena said most adults should aim to drink roughly three to four liters of water a day, depending on body size and activity level.

If you’re heading to the beach or pool this week, experts recommend packing sunscreen, a beach umbrella and plenty of water.

Doctors say taking simple precautions now can help keep you safe during the hottest days of summer.