All those fist-banging hot dogs that dance in the NFL end zones have a new way to keep their cool: air-conditioned shoulder pads.
Blowing cool, dry air under the soccer pads after vigorous exercise appears to keep core temperature low, reduce heart rate and make the player feel cooler, University of Florida researchers report. .
The specially designed pads have been used during (sideline) games by a number of NFL and college teams – including the Dallas Cowboys, Indianapolis Colts, Jacksonville Jaguars and United Bruins. ‘UCLA – but had not been tested for its effects on temperature, says lead author MaryBeth Horodyski, research director in the university’s department of orthopedics and rehabilitation.
Even small reductions in core temperature can be significant, she says. “Many don’t realize that it is not uncommon for athletes, especially South East soccer players in August and September, to have a core body temperature above 103 when competing.”
But as the body temperature approaches 104 degrees, a person may begin to experience heat illness from exertion, which can lead to a series of symptoms including feeling light-headed and mild nausea. Further increases in temperature put the person at risk of heat stroke.
Horodyski, who has no financial interest in the equipment, presented the results last week at the American Orthopedic Society for Sports Medicine’s annual meeting in Orlando. Investigators tested 15 athletes under two conditions in a room heated to 92 degrees.
In the first condition, the athletes jogged and sprinted on the treadmill while wearing a t-shirt, shoulder pads, shorts, a football shirt on the pads and a helmet. In the second, the same athletes performed the same exercise, but the air cooled to 60-65 degrees was pumped through special shoulder pads during the rest and recovery sessions.
In both conditions, the athletes completed three 15-minute exercise sessions separated by 10-minute rest periods, followed by a 20-minute recovery.
At regular intervals, the researchers measured core temperature (via an ingested sensor), heart rate, body weight and fluid intake. They also measured participants’ subjective impressions, such as perceived body heat and thirst.
Subjects in the cooling group displayed significant differences in core body temperature at the end of the second cycle of rest and at five, 10, and 15 minutes of the recovery period. The biggest difference occurred during recovery, when the cooling group displayed an average core body temperature of 100.3 degrees Fahrenheit, compared to 101.7 degrees for the control group.
Athletes in the cooling group also recorded an average heart rate significantly lower than in the control group, of around eight to 10 beats per minute.
“It’s extremely important to test new devices in randomized controlled trials like this,” says Rebecca Lopez, heat and hydration researcher at the University of Connecticut.
Misused, cooling devices could lead athletes to assume their body temperature is lower than it is.