That loud fitness class could be making you deaf, study shows

UNITED STATES – In today’s trendy, nightclub-like fitness classes, the blaring music meant to push gymgoers through one more rep could also be putting their hearing at risk.

The sound levels in group exercise classes can reach as high as 108 dBA, a decibel scale adjusted for human hearing. That is as loud as a rock concert, according to some research. The thinking goes, the louder the music, the harder people will exercise. 

A group of researchers at the University of Southern California (USC) decided to put that theory to the test. Their findings: Turning down the volume will not kill the vibe – and it may save exercisers from long-term, noise-induced hearing damage. 

While not all classes hit rock-concert levels, most operate above the safe 85 dBA threshold. With instructors and participants often attending 30- to 60-minute classes multiple times a week, the damage can add up quickly.

“I see more younger adults, people in their 20s and 30s, coming in with hearing changes or ringing that doesn’t go away,” said Dr Janet Choi, a head and neck surgeon at Keck Medicine of USC who specialises in ear disorders and co-authored the study.

While age-related hearing loss has long been expected later in life, she said cumulative recreational noise exposure is shifting that timeline.

The study surveyed dozens of participants after both typical-volume and reduced-volume classes, measuring perceived exertion and motivation.

The team found that while music volume does affect energy levels up to a point, there is a ceiling. A plateau effect occurred at around 80 dBA.

“Once it hits around 80 decibels, it really doesn’t have to be any louder than that,” Dr Choi said. “That would protect hearing for both instructors and participants.”

Ms Jennifer Morgan, 50, attends Orangetheory in Utah three to five times a week. She recently tried Orangetheory’s newly launched Hyrox class, a workout composed of eight different exercise stations each separated by a 1km run. Paired with blasting music, Orangetheory advertises it as a test of strength and stamina. 

For Ms Morgan, the volume was also a part of the challenge. As coaches shouted over the soundtrack, it felt like “loud on top of loud”, she said. Her Apple Watch regularly flashed noise warnings.

After noticing another participant wearing earplugs, she bought a pair and now wears them religiously. “It’s lowered my anxiety about having so much stimulation,” she said. 

Ms Morgan finds it telling that some gyms offer earplugs at the front desk rather than lowering the music itself. 

“I understand that music can make or break a class,” she said. “But we need to be taking into consideration not only the patrons and their hearing, but also the long-term effects on coaches.” 

Orangetheory did not immediately respond to a request for comment.

According to the World Health Organisation, exposure to 100 dBA should be limited to 15 minutes. As volume increases, safe listening time decreases rapidly.

Noise-induced hearing loss affects roughly 25 per cent of adults and is typically permanent, caused by irreversible damage to the delicate hair cells of the inner ear. 

Even short-term overexposure can cause what audiologists call a “temporary threshold shift”, muffled hearing or ringing that can last for hours or days.

Over time, those shifts can accumulate into lasting damage. BLOOMBERG