Whistle blowing could cause referees to suffer hearing loss, a study of sports refs and the whistles they use has warned.

Western Michigan University professor Greg Flamme says it all started when one of his doctoral students mentioned how his hearing had declined after years of refereeing basketball games. After talking it over, the pair made a connection between the shrill sound of student's whistle and his hearing, Flamme told CBC News in Windsor Wednesday.

Flamme is a co-author of Sports Officials’ Hearing Status: Whistle Use as a Factor Contributing to Hearing Trouble, published in The Journal of Occupational and Environmental Hygiene.

“We wound up having him wear a portable noise dosimeter, which measures how much noise you’ve been exposed to while he was at a basketball game, doing sports officiating,” Flamme said. “Turns out he was exposed to nearly 36 times the maximum daily dose in that one game.

A single whistle blow ranged between 104 to 116 decibels, far exceeding safe noise levels.

"I did expect the numbers to be kind of high, but I didn’t expect them to be that high," Flamme said.

A factory worker, for example, shouldn't be exposed to a decibel level of 90, according to University of Windsor professor Colin Novak, who is an expert in noise.

"I definitely can see the link that they have found there. Whistle noise typically has a sound pressure level of about 105 to 115 decibels,” said the acoustics specialist. “A couple of whistle blows won’t do it but being repeatedly exposed to that level will cause various types of hearing impairments.”

Researchers started by asking officials how well they hear in general and if they ever experience ringing — known as tinnitus — in their ears after they finish officiating.

“The rate of tinnitus that was reported was much higher than we might have expected based on national norms,” said Flamme. “The same subjects reported hearing issues at a much higher rate that the norm in most of the Midwestern U.S..”

Researchers also measured the sound outputs of different whistles. They found just one whistle blow, anywhere between six and 90 seconds in length, could reach 100 per cent of what would be considered allowable for human hearing.

Whistle maker disagrees

Researchers found Canadian-made Fox 40 whistles were used by more than 50 per cent of the referees studied. Those whistles rang in, on average, at 106 decibels per tweet. According to Flamme, damage could be done by whistles at that volume in 48 total seconds, which equates to roughly 96 whistle blows, each roughly half a second in length.

The company, based in Hamilton, Ont., said the conclusions of the study were simply incorrect.

“It is common knowledge that short blasts that allow the ear drum to rest between blasts will not cause damage … unless you're blowing the whistle continuously into your own ears for 48 seconds, the whistle should not cause harm,” according to the company's written statement to CBC News.

The organization went on to jokingly add, “A referee should not be in a position to continuously use his whistle for 48 seconds … if a referee ever blows 96 penalties in 48 seconds then he should give up refing.”

The company said that constant noise from music, noise-makers, and buzzers at the games were to blame — not their whistles — which they say are designed to push the noise way from the ref.

“We know that whistles are potentially a factor, but we can’t rule in or out the factor from exposure to crowd noise or music or other factors that the person may be involved with,” said Flamme. “All we can say from this is that we can’t rule out the whistle as a potential contributor to hearing impairment … stadium and crowd noise is a whole other study.”

Researchers recommend changes

Flamme recommends preventative measures, but he said most referees feel like they hurt performance.

“When goalies started to wear masks … the complaint was it would impair their ability to play the game properly, but when they got a puck in the face a couple times they changed their ideas. I think the referees have to do the same thing,” according to Novak.

Windsor, Ont., referee Geoff Astles, who officiates high school, college and university basketball games, has been on the hard court for 18 years and he hasn’t notice a drastic change in his hearing.

“I honestly don’t feel like it’s been a problem for me, but in fairness, I didn’t take a test 18 years ago to compare it,” said Astles, who added that his hearing wasn’t all that great to begin with.

He said just because he hasn’t noticed a difference, doesn’t mean researchers are wrong.

'It's my hearing, so I'm concerned.'— Referee Geoff Astles

“It’s my hearing, so I’m concerned. The newer whistles definitely have a higher pitch,” he said. “Obviously you need people to hear you so they can stop the action … you also want to blow the whistle strongly. If you don’t, coaches may question your call because you don’t seem confident.”

Music and noise makers have added to crowd noise so a louder whistle came in to play in the last few years, Astles said.

Even if the whistle is costing him his hearing, Astles said he would rather wear ear protection than stop hitting the hard wood.

“I’m not sure coaches would appreciate me wearing the ear plugs,” he joked. “but that’s something I might think about down the road."

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