Hey, listen up, Chiefs fans … that is, if you can still HEAR.
What? No. We didn’t say REAR.
Thank you, that would be nice.
But, no, sorry, what we said is that if, IF you can still hear after attending Sunday’s sacking of the Oakland Raiders and enduring the crowd’s record-breaking 137.5-decibel roars, you might try listening to the voice of Kansas City audiologist Jim Robertson.
The good doctor, an ear specialist for 39 years, knows that most of you will probably choose to tune out his warning of ear damage as killjoy blathering.
“They’ll just think I’m being a crank, right?” he said Tuesday.
Still, his quiet message is clear: Arrowhead Stadium’s noise may help the Chiefs, but it’s probably hurting your ears. Robertson isn’t the only one saying smart fans should think about taking precautions.
“I don’t want this to be a spoilsport thing,” said physician Hinrich Staecker, an expert on hearing and balance at the University of Kansas Hospital, “but people ought to be aware.”
Aware, for instance, that decibel readings are logarithmic, meaning that every 10-decibel increase equals a 10-fold increase in sound pressure. That means that a reading of 20 decibels is 10 times more intense than 10 decibels. A reading of 30 decibels is 100 times louder and 40 decibels is 1,000 times more intense.
A reading of 120 decibels is a rock concert at someplace like the Sprint Center; 130 decibels is like standing 100 feet from a jet engine.
Arrowhead on Sunday, according to an adjudicator for the Guinness World Records, reached a peak intensity of 137.5 decibels.
Both Robertson and Staecker point to the Occupational Safety and Health Administration, which publishes guidelines on “permissible noise exposure” in the workplace. According to OSHA rules, workers should spend no more than 30 minutes in an environment of 110 decibels, a noise equal to somewhere between a power mower and a pneumatic riveter, without ear protection.
At 115 decibels, it’s 15 minutes or less. In general, the time is cut in half for every 5-decibel increase: 7.5 minutes at 120 decibels, 3.25 minutes at 125 decibels. At 135 decibels, permissible exposure is less than 50 seconds.
“As much as I can enjoy the so far winning season of the Chiefs, as someone who has been practicing audiology for 39 years, I have concerns about the stated noise levels,” Robertson wrote Monday in an email to The Star. “I realize that with all the rah rah going on right now, it would be difficult to focus on anything negative about those noise exposures…
“I cannot stress enough that hearing protection devices must be used at Arrowhead if these dB levels continue as they surely will with this winning season.”
Staecker, the KU physician, said that on Monday his office received calls from Arrowhead fans who found their ears still ringing. That’s a sign of hearing damage.
Harm can come in two ways or a combination: damage to the ear’s outer or inner sensory hair cells, or damage to the connection between the ear’s inner sensory hair cells and the endings of nerves that transmit sound to the brain.
“The connection between the inner hair cells and the nerve endings can snap off,” Staecker said.
Just as shooters wear ear protection when firing guns, more fans might think of doing the same, he said.
Although the ringing can go away, research suggests that even damage that seems temporary may have long-term consequences, causing loss in hearing perhaps years after the initial insult.
“Even if the hearing seems to recover,” Staecker said, “some permanent damage is done.”
In principle, Tom Mardikes agrees, although he is less alarmist.
A former Chiefs season ticket holder, Mardikes also is a professor of sound design and chairman of the theater department at the University of Missouri-Kansas City.
He maintains that although prolonged exposure at such high decibel levels is unquestionably bad, the exposure at Arrowhead is far shorter than the three-plus hours that a game lasts. The noise spikes with the action.
“There are two big definitions we work with,” Mardikes said. “The 120 decibels is the threshold of feeling. It is where you feel discomfort 50 percent of the time. The threshold of pain is 140 decibels. That is where you feel pain 50 percent of the time.”
Arrowhead’s noise, he said, is “below the threshold of pain. Is it safe?”
He thinks on it.
“The thing is ...,” he said, “how long you’re exposed to it.”
The way Mardikes figures, although the noise at the stadium is intense, it tends to spike for a few seconds with the action and when the defense is on the field.
“It isn’t that long,” he said. “If you’re looking at your total exposure over the course of the game, it is going to be less than 60 seconds, two minutes or three minutes. If you look around, a lot of people are yelling, but they also have their fingers in their ears.”
Certainly, ear protection is a great idea, but if not …
“As long as they have a great defense,” Mardikes said, “I think it’s worth it.”