The Packers have been practicing in weather similar to the Vikings. In recent days, temperatures have climbed into the 90s with a heat index of well over 100 degrees. Trainers constantly are filling up water tanks and supply Gatorade to players during practice. They also watch players as they practice to help identify the cause on an injury, or if a player is becoming dehydrated.
"They're encouraged to hydrate by our trainers," said Sherman. "I'm sure they did a little bit more of that today because of the circumstances. We try to enforce hydration all the time."
Heat stroke is defined as a core body temperature in excess of 105 degrees with associated central nervous system dysfunction in the setting of a large environmental heat load that cannot be dissipated. Frequently encountered complications include respiratory distress, intravascular coagulation, renal or liver failure and seizures.
Exertional heat stroke generally occurs in young, otherwise healthy individuals who engage in heavy exercise during periods of high temperature and humidity. Typical patients are athletes or military recruits in basic training.
Stringer took part in the Vikings morning practice on Tuesday. But he reportedly vomited three times during the practice, then did wind sprints with the team at the end of practice.
The 6-foot-4, 338-pound Stringer walked to an air conditioned shelter following practice. There he developed symptoms of heat stroke including weakness and rapid breathing. The Vikings athletic trainers were present and immediately attended to him. An ambulance and paramedics were called and the hospital was alerted as the ambulance was en route to Immanuel St. Joseph's. Within five minutes a full team of physicians and emergency room staff met them upon arrival at the hospital.
Stringer was unresponsive at the time of arrival and had an extremely high core temperature of over 108 degrees. Stringer developed multi-organ system failure throughout the day and night requiring the attention of multiple specialists and staff. He never regained consciousness and despite all efforts his heart failed at 1:50 a.m.
"Believe me we're no better than anyone else," Sherman said. " That could happen here. I'd never say that couldn't happen here. Those things can happen. When you step on this field you're at risk, whether it's a contact hit, blowing out your knee or heat stroke. We certainly don't have all the answers, and we're not going to pretend to. With situations like this, you look at it, try to do things better and make sure you're doing it right."
Stringer was drafted in the first round out of Ohio State by the Vikings in 1995.
"All of us in the NFL family are stunned and saddened by the death of Korey Stringer," said NFL commissioner Paul Tagilabue. "He was a popular and well-respected team leader and an active volunteer in the Twin Cities area. He had a burning desire to be the best and was a major factor in the Vikings' success since 1995. We extend our deepest sympathy to his wife Kelci and son Kodie.
"The dangers associated with dehydration and heat stroke are well known throughout the country, especially among amateur and professional athletes. At this time of the year, we urge everyone to use caution during workouts and heed the warning signs associated with heat-related illness. NFL medical staffs are extremely knowledgeable regarding the hydration of players, fluid replacement and other methods used to prevent heat stroke. However, we now will ensure that our clubs again review their policies and procedures in this area."