VIRGINIA BEACH, Va. (WAVY) — When the black flag flies at JEB Little Creek-Fort Story, even the elite squadrons are advised to chill out a bit and take the exercise indoors.

The Navy uses a colored flag system to let sailors and their families know how dangerous it is and how to stay safe.

“So a lot of our leadership does stress to the younger sailors who do feel kind of invincible that heat effects everybody,” said Command Master Chief Christopher Farrar said.

Farrar knows first-hand about the dangers of heat.

“I myself suffered from a heat casualty,” he said. “I was a young sailor in the Persian Gulf and it exceeds 130 degrees. We were doing some vessel-board search-and-seizure stuff and I fell out because I was not hydrated properly.”

When the temperature hits 90, they hoist the flag, send out text alerts and ping email inboxes all across the base with the warning and ways to stay safe.

“We hydrate, hydrate, hydrate,” said MWR Director of Fitness, Sport & Aquatics Susan Lowry.

Lowry walks the walk with a water bottle in hand at all times.

“Your body is your machine,” she said. “It’s the only thing you have, so you want to make sure you treat it just like your car — well.”

That means checking the oil, or in your body’s case, the urine.

If it’s dark, you drink more water. Lowry said in this heat, you need about a liter of water an hour, up to 12 liters a days.

You also must listen to your machine when it talks to you.

If you start cramping, or you get blurred vision or clammy skin, you need to cool down and get help immediately.

Even if you are used to strenuous or intense physical workouts, Lowry said it takes the body about seven days to acclimate into weather like this. Many think they’re acclimated after a few days and try to go harder, but she warned that’s when people end up getting hurt.

If you’re on the base and do exercise outdoors, do it early in the morning or later in the evening when the black flag comes down.