NEW ORLEANS — A mother's instinct was spot on.

"I just had that instinct like something's wrong," Jennifer Vaccaro said

It has been scorching hot this month. Football practice is starting, kids are outside and there is a danger many people probably never think about.

Heat exhaustion is not the only thing to be on alert for and two mothers found that out the hard way.

It was two years ago, in the scalding summer heat when Jennifer Vaccaro rushed to her teenage son Nick's side in the emergency room.

She had a flashback only a parent can understand.

"When you're looking at him lying there in so much pain and just panicking and thinking, what's the matter, I see my eight-pound-nine-ounce baby, you know?" Jennifer said.

Moments before, the 6’1, 250 lbs. football player was working out on the practice field at Archbishop Hannan High in Covington. Jennifer was in the parking lot. Her phone rang. It was another mother.

"She said, 'You need to get back here. Something's really wrong with Nicholas.' I pulled out my phone immediately and called 911 as soon as I looked at him. He looked awful. He was screaming," Jennifer recalled.

"I went over to get water and there was like a rush that hit me. I threw up and then I fell on the ground and then I got a cramp in my right leg, and then it just started taking over my whole body. And I was getting cramps everywhere," said Nick Vaccaro, a Senior at Archbishop Hannan High.

The pain lasted for hours in the Emergency Room.

"They were pushing so much fluid into him so quickly and the minute a bag would empty, he would immediately start screaming," Jennifer said.

Nick stayed in the hospital for four days. He was at risk for kidney failure.

"They said if it didn't get any better, I was going on dialysis. I was pretty scared," Nick said.

Nick was experiencing something called Rhabdomyolysis.

"Rhabdomyolysis is a condition, it literally means break down of muscle tissue," explained Pediatrician Sports Medicine Physician Dr. Aaron Karlin, Chairman for the Department of Physical Medicine and Rehabilitation at Ochsner.

Dr. Karlin treated Nick. He says Rhabdo can happen to anyone during extreme exertion, whether you are in shape or not, but he sees it more in teen athletes. And having heat illness, puts you at higher risk.

"It's important to recognize it can happen anywhere. It can be 75 degrees outside, but incredibly humid, and you can be at risk for heat illness," said Dr. Karlin.

With dehydration and sweating, you are depleting your sodium and electrolytes. You can get heat cramps which are severe muscle contractions. And with exertion from the workout, that can lead to Rhabdo. Then as the muscles break down, your kidneys have difficulty filtering the onslaught of protein.

One year later, almost to the day, the same thing happened at practice to St. Paul's player Wayne Galloway.

"It was the most painful experience I've ever been through," remembers Galloway, a Senior at St. Paul's Catholic School in Covington.

"Some boys had called their moms crying, other football players …  some of them honestly thought he was dying," remembers Wayne's mother Melinda Ensley.

Teammates and coaches got him in the back of a pickup truck and rushed him to the hospital.

"As soon as the IV went in me, like my whole body felt different. Like, it was just like a big relief," Galloway remembered.

"One of the coaches said to me a couple of days later, he said, 'I'm glad you weren't there and you didn't hear him scream,'" Ensley recalls.

The two moms met on Facebook, both now sharing the fear of losing healthy sons. They want to make sure no other family goes through this.

Since everyone's body weight and sweat amount varies, Nick now has a precise formula for his fluid intake.

Every Sunday, gallon jugs of AdvoCare Rehydrate are mixed with water to take on the practice field for the week. Dr. Karlin stresses before practice athletes need higher sodium and electrolytes from drinks like Pedialyte or Gatorade, along with water. Often they are mixed half and half to lower the sugar and chance for stomach cramps.

"What you take in, 30 to 60 minutes before a workout, is of importance. What you do two and four hours, often times is actually urinated out beforehand," Dr. Karlin said.

Years ago, Dr. Karlin created detailed guidelines for sports in the heat. St. Tammany was first in the state to adopt it.

A green flag day is up to 89 degrees heat index, providing ample amounts of water.

A yellow flag day is in the 90s heat index. Coaches should reduce time of outside activity with mandatory water breaks.

A red flag day gets in the 100s. Equipment should be removed and players allowed time to change out of their wet clothes.

A black flag day is the most dangerous, hotter than 110 heat index, and all outdoor activity must be stopped.

The coaches and athletic trainers at Hannan tell students they are free to get water whenever they want. And there are mandatory drink breaks. In the locker room, there is a color chart on urine. They have been taught that clear to slightly yellow urine means you are hydrated.

And there are two daily weigh-ins to see how much water weight players have lost, and how much they replaced at home.

"As long as the next day they come in, they're within five pounds, I'll let them practice. If they're not, then I won't let them practice," said Hannan Head Football Coach Scott Wattigny.

"It's like a car. You put fuel in it. If you don't fuel up your car, you're not going to go very far, so same thing with your body," said Eric Richardson, a licensed athletic trainer with the Ochsner Sports Medicine Program who works at Hannan High.

Both Richardson and Coach Wattigny were there when Nick went down.

"It was a life lesson I think for all of us, myself, for our trainer, for our principal, for our school, for Nick and our entire football program," Wattigny said.

And a lesson for Wayne as well.

"Now I drink Pedialyte, you know, nights, before practices, and then during the season I drink at least one or two bottles a day," Galloway said.

"Wayne has his water. Wayne uses Pedialyte, power aid," Ensley said.

"We're excited to see him play again. We love watching him play. We love everything that he gets out of football, but that fear that it might happen again, is always present," Jennifer said.

But now as both boys enter their senior years, they are armed with more health knowledge and the realization that even in youth, life can be cut short.

And the doctor says if you are just 5% dehydrated, you can only perform at 80% ability. And at 9% dehydrated, you go down to just half of your normal ability.