The heatstroke death last August of Minnesota Vikings offensive lineman Korey Stringer made national headlines  and graphically illustrated the dangers of dehydration while exercising.

Stringer, 27, died of multiple organ failure due to heatstroke after collapsing at the end of an intense preseason practice held in stifling heat and humidity.

It was the first recorded heatstroke death in the National Football League.

Stringer’s death serves as a wake-up call to those who underestimate the importance of proper hydration during exercise, especially in the kind of heat that is just around the corner for Kansans.

John Thyfault, a doctoral student in exercise physiology at Kansas University, knows firsthand what it feels like to struggle with heat illness and dehydration.

Thyfault, 26, played football at Fort Hays State University.

“I actually lost 10 pounds in a football practice one time during college  I went from 195 to 185,” he said. “I was dizzy, my mouth got dry and I couldn’t even swallow.”

His advice to people exercising in hot weather is simple: “Drink, drink, drink.” Water, that is  or any of the specially formulated sports drinks like Gatorade that are on the market.

Even if it’s not terribly hot out, fluid replacement during exercise is critical to performance and health.

“If you don’t have enough water in your bloodstream, the blood becomes viscous (syrupy), and it’s harder for the body to maintain blood pressure,” said Thyfault, who serves as strength coach for highly ranked youth tennis player Caitlin Collins of Lawrence. “Water is important for your metabolic functions, the reactions that go on in your body all the time.”

The importance of fluid replacement during exercise is a message that Lovena Tuley, a physical therapist at Lawrence Memorial Hospital and a personal trainer, drills into her clients.

“If you’re not drinking enough water, you may be sabotaging your efforts and setting yourself up for failure before you even start,” she said. “Your muscles are already not in their optimal condition.”

Tuley, 29, speaks from experience. She has competed in fitness and body-building sports since 1996.

“To me, water is part of your workout gear,” she said. “You have your water bottle beside you, and you constantly sip off it. Just like a good pair of tennis shoes, it’s a must.”

Any signs of thirst mean the body already needs hydration.

“With your car, you don’t wait until your gas tank is flashing on empty before you refill it,” Tuley said. “During exercise, you need to keep yourself in optimal condition all the time.”