The question: Does making your exhale longer than your inhale calm you down more than breathing with equal inhales and exhales?
The short answer: In a 12-week randomized trial at Vanderbilt, 99 healthy adults practiced slow breathing with either a longer exhale or equal inhales and exhales, and both groups reported significantly less anxiety. The longer-exhale group improved slightly more, but the difference was small and not statistically significant. Because there was no group without a breathing program, the trial can't separate the breathing itself from the instruction and attention.
What the study did
A team at Vanderbilt University recruited 99 healthy adults aged 30 to 60. People with anxiety disorders were excluded, and people who were already very relaxed were screened out. For two weeks, everyone learned the same basic slow breathing. They were then randomized for 10 weeks: one group gradually made the exhale longer than the inhale, and the other lengthened both phases equally. Each person had a private 45-minute weekly class with a yoga teacher, practiced at home about five times a week, and wore smart shirts that recorded their breathing for a week at a time. The study called it focused breathing, not relaxation. Anxiety was measured with the PROMIS Anxiety questionnaire.
What it found
PROMIS Anxiety scores dropped by about 5.4 points in the longer-exhale group and about 4.3 points in the equal group. Both drops were statistically significant compared with where each group started. The gap between groups was about 1.1 points, which the researchers rated a small effect, and it was not significant (p = 0.35). On resting heart rate variability, the high-frequency measure went up in both groups, slightly more with the longer exhale, but none of those changes were significant. RMSSD also didn't change significantly in either group. By the end, both groups averaged under three breaths a minute in class, reached gradually over months with a teacher.
What it doesn’t show
There was no group that skipped breathing practice, so the trial can't say how much of the improvement came from breathing rather than weekly classes, attention or expectations. A non-significant gap is a small lean, not proof that the two patterns are equal. Participants were healthy adults, not people with anxiety disorders. And people reporting less anxiety is a different claim from a physiological measure improving.
Key points
- Both longer-exhale and equal-ratio slow breathing were followed by significantly lower anxiety scores over 12 weeks.
- The longer exhale leaned slightly better, but the gap was small and not statistically significant.
- Jesse's teaching takeaway: treat the longer exhale as an option, not a requirement, and don't force extra counts if they make your practice a struggle.
Common questions
Why are longer exhales supposed to be calming?
Your heart rate naturally speeds up on the inhale and slows on the exhale, a rhythm called respiratory sinus arrhythmia. The idea is that more time on the exhale means more of the calming phase. This trial tested whether that adds a measurable anxiety benefit over weeks.
Should I stop using a longer exhale?
No. The longer-exhale group improved too, and failing to show an extra benefit doesn't make a technique useless. Jesse suggests using whichever pattern feels comfortable.
Did anyone feel lightheaded?
Lightheadedness was the most common side effect during classes, reported nine times, and all events in class were rated mild. Participants worked down to very slow breathing gradually with a teacher, so the very slow pace they reached isn't a target.
Study cited: Birdee, G., Nelson, K., Wallston, K., et al. (2023). Slow breathing for reducing stress: The effect of extending exhale. Complementary Therapies in Medicine, 73, 102937. https://doi.org/10.1016/j.ctim.2023.102937
Practice this: Coherence Breathing (5 In, 5 Out) for Stress Relief | 10 Min
Read the full transcript
Auto-generated from the video captions, so expect small errors.
Welcome back to the Breathworks channel. I'm Jace. This is Decoding Breath. You've probably heard this advice. If you want to calm down, make your exhale longer than your inhale. It sounds simple until you're running out of breath. You've still got three counts left, and now relaxing has become another thing you're trying to get right. Are those extra seconds at the end actually helping? So, a 12-week randomized study at Vanderbilt put the question to the test. People practicing longer exhales reported less anxiety, but so did the people whose inhales and exhales were the same length, and the longer exhale group didn't demonstrate a significant advantage. We're
going to get into this. So, here's the short answer. The study didn't establish that a longer exhale was better for reducing anxiety, but don't throw out your favorite breathing exercise just yet. There is a difference between a practice helping and one particular feature being the reason why it helps. And when the researchers looked beyond how people felt, the story got more interesting. So, let's start with why the longer exhale idea makes sense. So, your heart rate normally changes with your breathing. Often speeding up, and you can check this. Speeds up during your inhale, and it slows down during your exhale. The rhythm has a name,
and it's called respiratory sinus arrhythmia. Now, you can see the appeal. If the heart slows on the way out, spend more time on the way out, right? So, more of the calming part should mean more calm. It's a relationship hypothesis, but your heart slowing down during one exhale isn't the same thing as you feeling less anxious weeks of practice. That explanation gets us to a question. It doesn't get us to an answer. Gergely Berdi and colleagues tested it in a study published in complementary therapies in medicine in 2023. They enrolled 99 healthy adults in a program that began with two weeks of basic slow breathing
instruction. Eligible participants then spent 10 weeks practicing one of two patterns. One group gradually made their exhale longer than their inhale. The other group gradually lengthened both phases equally. Both had private instruction and both had home practice. So, the comparison wasn't breathing versus doing nothing in the study. And both groups were doing the work. The question was whether the extra time on the exhale added something. To find out how people felt, the researchers used the promise anxiety questionnaire. It measures reported anxiety symptoms, not whether someone liked the exercise. A lower score means fewer symptoms. And the scores went down in both groups. The longer exhale
group improved by about 5.4 points. The equal group improved by about 4.3 points. Those are questionnaire points, not percentages. And both reductions were statistically significant compared with where each group started. So, yes, people in both programs reported less anxiety. That part of the result is clear. But, look at those numbers and it's tempting to say 5.4 beats 4.3, right? Longer exhale's won, right? Well, not so fast. The difference was about 1.1 points. And people's responses varied enough that the study couldn't establish a statistical significant advantage for the longer exhale. So, both groups improved significantly. Neither significantly outperformed the other. That's the questionnaire finding, and that's
the one I want you to remember. It doesn't prove the patterns are exactly equal, though. It means this trial didn't demonstrate that extending the exhale gave people an extra anxiety benefit. And because there was no group receiving no breathing program, we can't say how much of either group's improvement just came from breathing alone rather than instruction, expectations, or other changes over time. Now, there's another way the longer exhale could have stood out. Maybe the two groups felt better by similar amounts, but their physiology told them something different. The researchers also measured heart rate variability, or HRV, the variation between heartbeats. Their main HRV measure, high-frequency
HRV, didn't improve significantly in either group, and it didn't show a significant advantage for the longer exhale group, either. So, the questionnaire and the main HRV measures gave different results. People reported fewer anxiety symptoms, the researchers didn't find a corresponding significant improvement in that HRV measure. It doesn't mean the improvement people reported was imaginary. It means I feel less anxious and this physiological measurement improved aren't interchangeable statements. Now, we shouldn't use one as proof of the other. And notice what happened to that convincing explanation we started with. A longer exhale was supposed to give us more of the calming effect, but in this trial, it
didn't establish an advantage on either the anxiety questionnaire or the main HRV outcome. That matters the next time you're halfway through a breathing exercise stretching the exhale because someone said equal length breathing isn't good enough. So we did see some results, but would I tell you to abandon a comfortable equal length practice on the strength of this research? No. The people using equal length breathing also reported significantly less anxiety and a longer exhale group didn't demonstrate that it did better. Would I tell you to stop using a longer exhale technique if you liked it? Also, no. Failing to establish superiority doesn't make an exercise useless.
My teaching takeaway is simpler. Treat the longer exhale as an option, not an admission requirement for a technique. If adding those extra counts makes your practice struggle, this study doesn't give you a reason to force them in a pursuit of some proven extra benefit. That benefit wasn't established in this test and there's a detail worth remembering before you try to reproduce the experiment. These participants developed very slow breathing with repeated instruction over weeks. Some reported light-headedness. This isn't a challenge to see how slowly you can breathe and it's not a reason to push through dizziness or distress. They had people guiding them. It also wasn't
an anxiety disorder treatment trial. These were healthy adults and people with anxiety disorders were excluded. The result shouldn't be used to replace professional care. So, if you take one thing away, let it be this. Both breathing groups improved on the anxiety questionnaire, but making the exhale longer didn't demonstrate a significant extra benefit. You can keep a longer exhale in your options without turning it into a rule everybody has to follow. The next time you hear longer is better, you've got a useful question to ask. Better than what? And better on which outcome? Have you ever made a breathing exercise harder because you thought longer exhales
were the part that made it work? Tell me in the comments. This study and our free circle community are linked in the description if you'd like to keep this conversation going. Next, we're looking at humming and nasal nitric oxide. When a breathing practice makes a measurement go up, how do we know that it's actually a benefit? That's where we're going to go next in next episode. So, thanks so much for watching. We'll see you next time.