up the beat – not the volume!

A comparative study shows that many instructors are still cranking the volume in classes up too high for safety.

Since the golden days of aerobics, when leotards, legwarmers and headbands were the height of fitness fashion, music has been an integral feature of group exercise. Back then classes were loud – both the music and the fashion! In today’s group exercise studios the fashion has quietened down, but the music remains as loud as ever.

Along with my team from the National Acoustic Laboratories, I teamed up with the University of Newcastle to compare noise levels in today’s fitness classes (2009-2011) with those recorded over a decade earlier (1997-1998). In total, we measured noise levels in 100 fitness classes in Newcastle and Sydney. We found that while noise levels in low-intensity classes (like BODYBALANCE™ or BODYPUMP™) have dropped slightly, noise levels in high-intensity classes (like Spin or BODYCOMBAT™) are higher than ever, with an average noise level of 93 decibels.

The graph in Figure 1, opposite, shows how the different class types compare. The Spin/RPM™/Cycle class can be seen to be the noisiest class type, with the noise level reaching as high as 99 dB – about as loud as an average nightclub. Some participants we spoke to came out of their Spin classes wearing earplugs – they loved the workout but hated the noise!

  • A comparison of fitness classes from 2009-2011 with those from 1997-1998 found that noise levels remain too high in many classes
  • Indoor cycle classes were the noisiest class type – with the noise level reaching as high as 99 dB
  • Exceeding recommended workplace volume levels increases your likelihood of sustaining hearing damage – and may be unlawful
  • Research from physiology labs suggests that increasing the tempo, not the volume, is the best way to get your class moving.

So what do these findings mean – and what are the implications for your health, safety, and ultimately your hearing? Australian workplace health and safety laws stipulate that our noise exposure at work must not exceed an average noise level of 85 dB over an 8-hour period. With every 3-dB increase in noise level, the time period must be halved. So while 85 is considered to be acceptable for eight hours, 88 dB is only OK for four hours, and 91 for two hours, and so on. For volumes of 94 dB (around the average of high-intensity classes), the maximum daily dose is one hour. Exceeding this noise dose increases your likelihood of sustaining hearing damage.

Let’s think about this from your point of view. You’re a casual fitness instructor teaching six 1-hour classes a week. On Mondays and Tuesdays you teach a 1-hour class where the noise level is 94 dB. So far, so good. But on Wednesday, you teach four hour-long classes. Remember, the allowable noise limit for four hours is 88 dB, but if the output from your sound system is at 94 dB, by the time you have finished work for the day, you will have exceeded the daily legal noise limit four times over. This has implications for you and your employer – you may be damaging your hearing, and he or she may be breaking the law.

Remember also that noise exposure is cumulative and teaching fitness classes may not be your only source of exposure. If you do anything where the noise level exceeds 85 dB (e.g. work a second job, use power tools, visit nightclubs, or even attend fitness classes yourself), then your total noise exposure will be even higher and your risk of hearing damage increases.

There’s some troubling new evidence that noise-related hearing damage could have far-reaching impacts on our health and wellbeing, and at a younger age than first thought. Researchers have discovered that noise exposure (at the typical noise levels found in fitness classes) damages the neural connections which transmit sound from the ear to the brain – making it hard to hear, especially in noisy places like cafes, bars and restaurants. You might not notice it at first – and you won’t yet need a hearing aid – but damage has occurred. Often the first sign is when people find it hard to hear and participate in conversations. This can make socialising frustrating and tiring, causing some people to withdraw from social situations. Social withdrawal can lead to isolation which, in turn, can lead to early cognitive decline, something we all want to avoid!

You might think that damaging your hearing or experiencing some hearing loss isn’t such a big deal. After all, most of us will suffer some sort of hearing loss by the time we reach 70 – and that’s ages away, right? Besides, if it does happen you can always get a hearing aid – surely that fixes everything? But it’s not that simple. Even though age-related hearing loss is common, we know that many people who are exposed to noise throughout their working lives end up with hearing loss that is more severe and/or starts earlier than it would otherwise. And despite huge advances in hearing technology there is no device that will fix or restore your hearing in the way, say, that glasses ‘fix’ many vision difficulties. The best solution is prevention – decreasing your noise exposure and thus minimising your risk.

The good news is that turning down the volume could benefit more than your ears – it may also help your business. In our study we asked clients to nominate their preferred noise level. On a scale of 1-7, the clients chose ‘5’ (which equates to about 70 per cent of maximum volume) while instructors preferred a level of ‘6 out of 7’ (about 85 per cent). So, if you turn the volume down a little – say two or three dB, you’ll not only be protecting your hearing, you’ll be meeting the needs of your clients to boot.

But isn’t loud music a great motivator? Our research suggests that most instructors (around 85 per cent) believe that loud music is motivating, but not all clients agree. Around 30 per cent of clients told us that they considered loud music to be stressful, or have no effect at all. In fact, research from physiology labs suggests that increasing the tempo, not the volume, is the best way to get your class moving.

Figure 2, below, illustrates the noise output from a very loud RPM™ class where the noise level was 99 dB. At this level, it’s only safe to be exposed for 20 minutes. A 50-minute class like this is exposing the instructor to 2.5 times the daily workplace noise limit. You’ll notice also that apart from the first few minutes of warm up and the last couple of minutes of cool down, the noise level pretty much hovered between 94 and 102 dB throughout the class. The instructor cranked up the volume and left it there!

So what are some ways to use music in your classes and lower your risk? A better alternative might be to mix it up and use volume as a way of creating interest and variation in the class. Volume could also be used as a way of introducing interval training during a class: you could use low volume to indicate a low intensity period and follow it up with a higher volume to mark a high intensity period.

Better still, experiment with tempo. The advice from physiologists is that music tempo is the most important factor for increasing exercise speed and heart rate. Research conducted in cycle classes shows that increasing the tempo of music significantly increases cyclists’ pedal power, speed, and heart rate, so look for tracks with higher beats per minute rather than simply turning up the volume.

You could also explore other creative solutions to get your clients motivated. Why not consider using visual rather than auditory stimuli – or spice up your timetable by holding some ‘quiet’ classes? Advertise these to your participants and get their feedback – you might be surprised by how many people turn up.

As a health and fitness professional it makes sense for you to ensure your work environment is a safe and healthy one. Don’t work hard to improve physical health at the expense of your hearing health.

Here are some tips to help you deliver great workouts without causing hearing damage to yourself or participants:

  • Measure your noise levels. The facility you work in may invest in equipment such as the SoundEar, or you may download a smartphone app that gives accurate noise level readings.
  • Consider how many classes are taught each day and by whom – share the dose load to keep everyone safe.
  • Use this table to work out the safe noise limit for your classes.
    Noise level (LAeq) Maximum Daily Exposure Duration
    85 dB 8 hours
    88 dB 4 hours
    91 dB 2 hours
    94 dB 1 hour
    97 dB ½ hour
  • Mark the safe volume on your sound system and stick to it!
  • If you are the group exercise manager or facility operator, conduct regular audits – maybe once every three months. Make sure instructors are part of the process and make adjustments if you need to.
  • Experiment with tempo, visual stimuli and volume variation to get your clients moving and keep them motivated.
  • Talk with your clients and explain any changes and why you’re making them. Get feedback from all your clients – not just those who are the most vocal!

Remember, your hearing health is in your hands. By turning it down a notch, not only will you avoid hearing damage, you’ll also be better meeting the needs of your clients, and ensuring a truly healthy environment for all gym users.

What does Les Mills say?

Regarding volume in classes, Michelle Dean, training manager at Les Mills Asia Pacific, says:
‘When it comes to the volume of music within a club, this is something that is managed between the instructor and the club. If anyone is unsure about what the optimal volume should be, we recommend SoundEar – a tool that enables a club to measure and manage the noise level within their gym environment.’

‘Through ongoing education of our Instructors we teach them the importance of using their voice correctly – warming up, not shouting and how to deliver an amazing workout vocally without damaging their vocal cords. In addition to this, we educate them around the importance of a microphone and how to use it effectively when instructing classes.’


Elizabeth Beach is a researcher at the National Acoustic Laboratories. She began working in the area of hearing loss prevention after completing her PhD in psychology. Her main area of research is leisure noise, its contribution to overall noise exposure and how it might be affecting our hearing acuity. elizabeth.beach@nal.gov.au