Intro
Have you ever been going through your day, like the absolute superhero you are, and been like – “I just can’t speak – or sing – another word?” You’ve probably experienced vocal fatigue.
Welcome to The Voice Science Podcast, where we dive into the science behind all things singing and teaching. Here, you’ll learn how the voice works and discover practical tips to train it more efficiently. I’m Drew and I’ll be your guide for this educational episode about vocal fatigue.
A quick disclaimer: vocal fatigue is a very real thing, this episode is meant to provide education and entertainment. If you think you may be experiencing vocal fatigue please consult your doctor for medical guidance.
One more thing before we dive in, if you have questions about this episode or questions about the voice and singing in general, we’d love to hear from you. You can reach out to us on our website at voicescience.org/contact/. We’ll reach back out with an answer, answer your question in a future episode, or both.
What is Vocal Fatigue?
I like to define Vocal fatigue as: the sensation of increased difficulty phonating, felt through increased respiratory load and exhaustion of auxiliary muscles of phonation. This may be leaving you more confused than when we started so let’s dive in.
Muscles of Expriation
The first part is the sensation of increased difficulty phonating felt through increased respiratory load. As we get more and more tired and need to continue to speak or sing there is a natural tendency to try and push more and more air to be heard. This tendency starts to activate muscles of expiration like the internal intercostal muscles (one of the muscles between your ribs and several abdominal muscles. These muscles are used surprisingly rarely for respiration outside of exercise. Unfortunately, this increased respiratory load can cause increased sensations of vocal fatigue!
Muscles of Adduction
The second part of the definition is the auxiliary muscles of phonation. Rather interestingly study after study has found that the muscles of phonation are extremely fatigue resistant, what this means is that your vocal fatigue is almost certainly not actually a fatiguing of your vocal folds! However the same may not be true for all of the muscles that help your vocal folds to adduct. In this case, the Lateral Cricoarytenoids and the Interarytenoids. These muscles are absolute champs working day and night to adduct your true vocal folds but the increased load can make them tired.
But vocal fatigue is not just a sensation of tiredness; it can also be a very real increase in the effort to phonate. As you phonate for a period of time the viscosity of your vocal folds can increase. If you’re not familiar with the term viscosity, it is a term that most often is used to describe how liquids flow, honey, for example, has a high viscosity and flows slowly, whereas water has a lower viscosity and flows easily. When the viscosity of the true vocal folds increases there is an increase in the amount of subglottal air pressure that is required to start and sustain phonation. Additionally, in females, it has been shown that a majority will develop an anterior glottal chink, a small gap in the closure of the vocal folds at the front of the vocal folds when vocal fatigue occurs. This gap is literally leaking air!
Prevention
That’s great… but what can we do about it? Great! I’m glad you asked. There are three big things that science tells us that we can do. We can reduce vocal dosage, stay hydrated, and ensure recovery time.
Reduce Vocal Dosage
Vocal dosage is an interesting concept. Every time you speak or sing you are dosing, the vocal folds are slamming together at a rate determined by the fundamental frequency, which could be as low as a few dozen times per second or over a thousand times a second if you are singing a soprano singing a high C. All of those collisions, all of the pressure load, and all of the minutes and hours of usage combine to be your vocal dosage. As the dosage increases the amount of fatigue will increase, as well as the microscopic damage to the vocal folds, think of clapping your hands 10,000 times (something that is less than 10 seconds for that soprano), it would hurt right? We’ll be back to this in just a minute.
Stay Hydrated
A real key to fatigue prevention is hydration. I know you’ve probably been hounded to stay hydrated. Well for good reasons. A 2000 study by Solomon and DiMattia found that voice users who are dehydrated fatigue twice as quickly or put the opposite way. If you are well hydrated you can fend off vocal fatigue for twice as long! Depending on where you live and the time of year this is much easier said than done as humidity in the air also plays a significant role. So break out those humidifiers, but remember to clean them regularly… mold… ew.
Recovery
Now, remember the idea of clapping your hands 10,000 times? How long would it take for your hands to stop hurting? After 10,000 claps, the stinging pain would probably subside in a short while, but your hands would be tender for a while. Your true vocal folds go through a similar process. According to a 2009 study by Hunter and Titze, your true vocal folds recover 90% of the way in a few hours, taking a full 72 hours to recover completely. Showing the same recovery pattern as a chronic injury. The important takeaway is if you have a big day lots of speaking or perhaps a performance, or maybe you just went to that concert and sang your heart out. That is a significant vocal load and will require significant recovery.
If you are an individual who is more curious about the prevention of vocal fatigue while speaking rather than singing I also have two more for you. You can increase the brightness in your voice while speaking, we covered ring and twang in the last episode they are tremendous at reducing the intensity that you need to speak at to be heard. And there is a tendency especially for higher voices to lower their speaking voice for a whole host of reasons, this lowering of the fundamental frequency will potentially give you an air of authority or make you sound older but will make you work harder to be heard; raising the pitch of your voice just a little will help your listener’s brains hear you as louder.
Recap
Vocal fatigue is a real challenge for singers and speakers alike, but understanding what’s happening under the hood can help us prevent and manage it. We explored how fatigue isn’t just about your vocal folds wearing out—those tiny muscles are incredibly resilient—but rather the increased respiratory load and auxiliary muscle effort that make phonation feel harder over time. We also looked at how changes in vocal fold viscosity and closure can impact efficiency and contribute to that frustrating “leaky” feeling in your voice.
The good news? There are science-backed strategies to combat vocal fatigue. Reducing vocal dosage, staying hydrated, and allowing for proper recovery can make a huge difference in your vocal stamina. And for those who rely on their voice for speaking as much as singing, simple adjustments like increasing brightness and avoiding unnecessary pitch lowering can reduce strain and extend your vocal endurance.
Outro
That’s a wrap for this episode of The Voice Science Podcast! If you found this helpful, be sure to subscribe and leave a review—it helps more singers and teachers discover the science behind healthy, efficient voice use.
Got a question about vocal technique, pedagogy, or voice science? I’d love to hear from you! Reach out at voicescience.org or connect with me on social media.
Until next time, take care of your voice, stay hydrated, and keep singing smart!
Hunter, E.J., Titze, I.R., 2009. Quantifying Vocal Fatigue Recovery: Dynamic Vocal Recovery Trajectories after a Vocal Loading Exercise. Ann Otol Rhinol Laryngol 118, 449–460. https://doi.org/10.1177/000348940911800608
Pearl Solomon, N., Stemmle DiMattia, M., 2000. Effects of a vocally fatiguing task and systemic hydration on phonation threshold pressure. Journal of Voice 14, 341–362. https://doi.org/10.1016/S0892-1997(00)80080-6