In 1967, the Ice Bowl touted an incredibly cold kickoff temperature of 13 degrees below zero, according to the National Weather Service. Even worse, the wind chill was minus-36.
It almost makes five degrees above zero—the game-time temperature of this year's wild-card matchup between the San Francisco 49ers and Green Bay Packers—seem balmy.
Super Bowl XLVIII's forecasted temperature? As of Tuesday morning, AccuWeather.com predicts a high of 39 degrees with an evening temperature of 35.
At least, it should be.
With outdoor NFL stadiums set in locations such as Green Bay, Chicago and Foxborough, teams and medical staffs may need to prepare for cold weather at least a few times per season.
According to Dr. Matthew Matava—president of the NFL Physicians Society (NFLPS), Professor of Orthopedic Surgery and Sports Medicine at Washington University in St. Louis and head team physician for the St. Louis Rams—preparation begins well before kickoff, and it starts with reinforcing simple, well-known health principles.
"The team doctors and athletic trainers always recommend that players be especially vigilant to stretch prior to playing in the cold and to maintain joint flexibility and muscle elasticity by remaining active when not in the game," Matava remarked. "There will be a stationary bicycle on the sideline for this purpose."
Why the extra precaution?
"Any pre-existing muscle tear, strain or inflamed tendon will be at risk during cold-weather games due to the loss of muscle elasticity," he continued.
Player clothing may differ as well.
"The players will be outfitted in cold-weather clothes worn under their uniforms," Matava said. "This layer is typically made of modern synthetic material that is intentionally skin-tight in order to prevent the escape of body heat while wicking away sweat. Players will also often wear surgical gloves under their playing gloves to retain heat."
He added that athletes may also use petroleum-based ointment on exposed skin surfaces to reduce the effects of cold and wind. Players not in the game will receive parka-type coats to maintain body heat.
Snowy conditions add yet another variable into the equation.
"If significant snow is expected, players will use shoes with longer cleats to improve traction," Matava explained. "The medical team also worries about loss of balance and the increased risk for fractures and ligament tears that can occur during a slip or fall."
Equipment crews also stock the sidelines with some specialized equipment.
"When (it is) cold, there are space heaters that are very effective in providing heat to a few players at a time," Matava assured. "The benches also distribute warm air to the legs when a trap door is activated by the feet of a sitting player."
Even rehydration methods diverge from the norm when temperatures fall.
"Instead of water or sports drinks, players will often drink warm chicken broth to replenish fluid and electrolytes, as well as aid in internal warming."
Fortunately, adequate preparation and in-game warmth management almost always deter dangerous outcomes such as hypothermia and frostbite—diagnoses more common in events such as city marathons rather than NFL games.
Regardless, medical personnel must be ready.
"Obviously, frostbite and hypothermia can develop whenever the temperature drops below freezing," Matava stressed. "Symptoms of hypothermia include shivering, an increased heart rate and an increased breathing rate—all physiological responses to preserve heat. Mental status changes may also develop as the condition worsens."
Whereas hypothermia constitutes a global process within the body, frostbite usually affects focal areas in the extremities.
"Frostbite is seen with prolonged exposure to freezing or subfreezing temperatures and results from shunting of blood away from the skin due to the constriction of blood vessels exposed to the cold," Matava clarified. "This leads to damage of skin and underlying tissue, most often of the nose, ears, fingers or toes."
He added that cold air can also affect a player's airways by inducing a process known as "bronchospasm." In this scenario, the airways within the lungs of susceptible individuals tighten in response to the cold, sometimes leading to an asthma attack.
To safeguard against emergencies, players with a history of asthma will have an inhaler on the sideline in the event they develop difficulty breathing or wheezing.
Nevertheless, despite such potential cold-weather complications, the true threat of cold weather may rest not on the field, but in the stands.
"Fans should not attend games in extreme cold if they have any chronic medical conditions that reduce their ability to tolerate the cold," Matava warned. "They should dress appropriately—in multiple layers with skin covered—and get into a warm environment if they develop any signs or symptoms of frostbite or hypothermia."
He also cautioned against the masking effects of excessive alcohol consumption.
"Alcohol causes vasodilation—dilation of small blood vessels in the skin—which gives a warm, flushed feeling. (However, one) loses heat because the blood flow has increased. Ultimately, body temperature drops as a result of the heat that is dissipated through the skin."
On the field, NFL physicians and medical staff are not immune to the cold, either. Matava remembered one game in particular at, where else, Lambeau Field.
"The coldest game I have attended was a night game in Green Bay, Wis., in December when it was 18 degrees. It was definitely cold."
Similar to fans in the stands, sideline personnel cannot keep warm as efficiently as actively exercising players.
"The problem with being on the sideline is that you aren't able to generate body heat with activity as the players do. We always dress in layers and will often put hand warmers in our gloves and shoes. And we drink the chicken broth."
Yet just how cold does it get on the sidelines?
"On that particular night, I actually burned my face by placing it too close to the space heater," Matava recalled. "I will never do that again."
Dr. Dave Siebert is a resident physician at the University of Washington who plans to pursue fellowship training in Primary Care (non-operative) Sports Medicine. All quotes were obtained firsthand.