During her first workout at Orangetheory Fitness in Fairfax, Donna Reid was blown away by two things: “how hard it was and how loud it was.” The 51-year-old adored the studio’s interval training program — a mix of treadmill, rowing machine and resistance exercises — but when it came to the accompanying music assaulting her eardrums, well, that didn’t seem so sound.

“I want to do something good for my body. I don’t want to do something detrimental at the same time,” says Reid, who asked the trainer to turn down the volume. She got her wish for a few minutes. But when it soon crept up again, Reid knew she’d need a different tactic.

She’s settled on earplugs, which she brings without fail to her five Orangetheory sessions each week. A couple of classmates have commended this strategy, although they haven’t followed her lead. As for the rest?

“When it’s a song they like, they’ll yell out to the trainer to crank it up. I think they’re crazy,” Reid says.

At the very least, they’re probably not thinking about the potential ramifications of that request. Loud noise, like sun exposure, is the sort of thing that might not seem harmful at any given moment, but the cumulative effects can be devastating and irreversible, says Deanna Meinke, a professor of audiology at the University of Northern Colorado and co-director of Dangerous Decibels, a public health campaign targeting noise-induced hearing loss.

Asuka Boutcher teaches a dance class at her Springfield studio, Kazaxe, in December 2013. She says loud music is what gives her classes a club-like atmosphere that lets students lose their inhibitions. (Teddy Wolff/For Express)

Researchers have raised concerns about music at gyms since the 1980s, Meinke notes, but the fitness industry doesn’t seem all that interested in dialing it down. A study released last year by Australia’s National Acoustic Laboratories compared sound levels from fitness classes in 2009-2011 with those from 1997-1998. The finding: High-intensity offerings are even noisier than they were a decade ago, with indoor cycling classes topping the list of culprits, blaring tunes as loud as 99 decibels.

As a general rule, adults can safely tolerate 85 decibels for up to eight hours. But get even a tiny bit above that, and the time frame shrinks rapidly, Meinke says. The human ear can handle 91 decibels for two hours, and 94 decibels for just one hour.

A sign that it’s too loud: You experience ringing in your ears — tinnitus — after you’ve stepped out of the gym. You might also have temporary hearing loss, but the effect is often too slight to notice, says Matthew Bakke, chairman of the audiology department at Gallaudet University. If you think it may be too loud, it probably is. But the more you’re exposed to loud music, the less likely you are to mind it, he adds.

Once permanent hearing loss creeps in, however, you won’t be able to ignore that. The condition isn’t like sticking in an earplug, which muffles everything. Instead, soft sounds are blocked and loud noises seem to get louder, Bakke explains. That’s why, as we age, we tend to be bothered more by blasting music. (Or, as Bakke puts it: “I sound like a crotchety old man.”)

As seniors become an increasingly important target for the fitness industry, trainers need to take extra note of noise, says Bernadette O’Brien, an 84-year-old aerobics instructor, who raises these issues at conferences around the world. Music is an integral part of all of her classes — “It creates a mood, makes you feel nice and encourages you to move,” she says.

But turn it up too loud, and “the chronologically enriched” won’t be happy about it. “And they will tell you,” O’Brien adds. To prevent that, she recommends just 60 decibels for seniors.

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A Kazaxe class. (Teddy Wolff/For Express)

That’s a little overcautious, says Meinke, who notes that normal conversation is 65 decibels. Still, she’d like to see volume levels come down overall to that 85-decibel level, accompanied by an education push in gyms. Audiologists could lead classes in hearing health, Meinke suggests, and clubs could lend out noise dosimeters, devices that are worn throughout the day to measure cumulative exposure.

These days, however, you’d be lucky simply finding a fitness facility that has a noise policy of any kind — at least one that its management will discuss publicly. Orangetheory Fairfax declined to comment for this article, as did SoulCycle, the indoor cycling studio that’s recently added two locations in the D.C. area.

Booming bass may be bad for your ears, but it’s good for business, says Teri Bothwell, group fitness director of Sport & Health. The local gym chain trains instructors to keep their playlists near the 90-decibel mark by using sound monitors (which are now available as apps and accessible to anyone with a smartphone). That safety decision has led to occasional complaints from members demanding louder tunes, particularly in Zumba classes.

“They’re not happy, and some of them have gone somewhere else,” Bothwell says. “At boutiques, it’s a party and it’s loud, and that’s part of what people pay for.”

The ones who are really paying, however, are the instructors who spend countless hours in these environments. Even in gyms that pay attention to noise, “it’s the industry joke that we’re all deaf at 35,” Bothwell adds.

Asuka Boutcher, who teaches crowds of up to 300 students at her studio, Kazaxe, in Springfield, jokes that she’s surprised she can still hear at all. Loud music is what gives her dance classes a clublike atmosphere that lets students lose their inhibitions. “It’s a chance to be crazy and go wild. If the music’s too low, no one is going to work out to that,” she explains.

But while she’s willing to put her own hearing at risk, Boutcher recognizes that it’s not a laughing matter. That’s why she’s settled on the same solution Reid did: earplugs. There’s a big bucket of them available free for any student.

“It’s surprising other fitness classes don’t do it,” Boutcher says. “Because it’s an obvious thing to do.”