The above is the title of a paper published by Jim Knochel in 1975 – (Knochel J.P. Dog days and Siriasis. How to kill a football player. JAMA 1975 23:513-515). It immediately became a classic. The reason I bring it up in the depths of winter is because of the criminal indictment of a Kentucky football coach in connection with the death of one of his players from heat stroke.
The pathophysiology of heat injury has been understood for decades. The death of an athlete from heat injury is always preventable yet it still happens. Even the National Football League is not immune as the death of Korey Stringer shows. The lawsuit resulting from his death was just settled.
Knochel was and is the world’s leading authority on heat and exercise-induced muscle injury. He spent years studying the factors that cause muscle injury. He used this experience to outline exactly how lethal heat injury occurs in football players. His point was, of course, to show how not to kill a football player. Interestingly, Knochel himself had played football. If my memory is correct he was a fullback and a linebacker.
Heat injury (heat stroke is its most extreme incarnation) is far better prevented than treated. In football players almost all heat-related injuries occur in August. This is when football practice starts. The players after a long layoff are apt to be deconditioned. The weather is likely to be hot. It takes about two weeks of gradually increasing exercise to become heat acclimated.
Football practice should start at the coolest part of the day. Early morning is the best time. The duration of practice should initially be brief and gradually increased. Fluids should be freely available and fluid intake encouraged. But coaches and players should be aware that fluid losses cannot be fully replaced while the practice is underway. It may take a day for all the loss to be replaced. This is because losses continue during the practice and because blood flow is diverted from the gut to the muscles during exercise slowing fluid absorption.
Loose-fitting clothing should be worn during the period of acclimation. Sweating and evaporation are what cools the athlete. Full uniforms should not be worn during hot weather. Drugs that cause vasoconstriction and decrease sweating (eg amphetamines) should be avoided. Practices when the humidity is very high should be curtailed. The higher the humidity the less evaporation and less cooling from sweating.
Heat stroke can develop suddenly if extreme care during exercise in hot weather is not taken. Heat cramps and heat exhaustion are milder forms of heat injury. These too are preventable. Sports Medicine Australia has a policy statement that covers the problem in detail and which is well-referenced. This is a problem that has been solved. No football player should die from heat injury.