SATURDAY, May 21 (HealthDay News) -- Football players need to acclimate to hot weather workouts long before they hit the training field in August, an expert advises.

Doing so will help prevent cramps, dehydration and other potentially serious heat-related injuries, according to Dr. David Lintner, chief of the Methodist Center for Sports Medicine in Houston.

Heat-related illnesses have claimed the lives of nearly 40 U.S. football players since 1995. The majority of serious heat illness cases occur during the first four days of summer football practice, according to the American College of Sports Medicine. This is because most players aren't used to the heat, are unprepared for the intensity of practice, and are not used to exerting themselves while wearing equipment.

"If your first introduction to the heat is when you put on your pads and start hitting, you're not going to have the endurance, the strength or the concentration you need to succeed," Lintner said in a Methodist Hospital news release. "Not properly preparing for the heat could set you back three weeks."

He stressed, "Spending all summer indoors is not a good idea," even if players are taking steps to get stronger, such as lifting weights.

"A big part of the summer conditioning process has to take place outside. Whether it's basketball, running or working outside, the body needs time to get accustomed to the heat. If players don't get used to the heat, they open themselves up to serious heat illness and, in more serious cases, death," added Lintner, team physician for the Houston Texans and Houston Astros.

"You can get acclimated to the heat by starting off with 20 minutes a day and gradually work up to an hour. Taking a little time every day will make preparing for the upcoming season much more enjoyable and successful," he said.

More information

The National Athletic Trainers' Association has more about heat illness.