Heat dangers plague high school football practices.
New statistics are out on the number of heat-related illnesses suffered by high school athletes and most of the victims are some of the toughest guys out there.
A new report from the Centers for Disease Control estimates there are about 9,000 cases of heat illness among high school athletes every year.
Most happen in August and most are football players.
Earlier this week six high school football players in Florida were taken to the emergency room after some started vomiting during practice.
Six other players in Kentucky were also recently treated for heat exhaustion.
At the University of South Florida researchers are using pre-season camp to learn more about how exercise and extreme heat can lead to a medical emergency.
They're monitoring body temperature, sweat, heart rates and metabolism.
Researchers hope they'll be able to find ways to prevent heat exhaustion and heat stroke.
"By the time you get to heat stroke, you've really stopped sweating," says emergency room physician Dr. Lorraine Duncan. "Your body is not taking care of itself, you're not compensating for that heat building in your body, and you tend to get a little confused."
Doctors say the single best way to avoid getting sick is to stay hydrated.
Next to a helmet, water may be the most important piece of safety gear a football player can have.