Imagine a kettle on the hob, just before it boils. You are standing next to it with a letter in your hand, the one with the window in the envelope, and you can hear the pitch climbing. The lid is starting to rattle. Nothing has gone wrong yet, but everything in the kitchen feels one degree from loud. Now imagine lifting the kettle off the heat. The note drops. The steam thins. You have not fixed the thing that made the water hot, but the sound has come down far enough that you can hear yourself think.
Your breath is the closest thing you have to that kettle handle. And you already know how to use it, because your body does it for you when you are not looking. Somewhere between the hall and the kitchen, with that letter in your hand, your breathing probably goes quick and shallow and high in the ribs. Then, without any instruction from you, you take a double breath in and let out a long, loose sigh, and your shoulders drop half an inch.
You did not choose that. Your body did.
That small, automatic rescue has a name. It is called the physiological sigh: two breaths in through the nose, one on top of the other, followed by one long, slow breath out through the mouth. It shows up in sleep, in crying, and in the seconds after a fright. In 2023, a team at Stanford University asked a plain and useful question about it. If your body reaches for this breath by itself when it needs to, does doing it on purpose help?
This post looks at what they found, what the research cannot tell you, and how you can try it today, in about a minute, with nothing but the lungs you are already using.
What the Stanford study actually tested
The paper, “Brief structured respiration practices enhance mood and reduce physiological arousal”, was published in Cell Reports Medicine on 17 January 2023. It was led by Dr Melis Yilmaz Balban, working with the psychiatrist David Spiegel and the neuroscientist Andrew Huberman, among others, all at Stanford. The team recruited just over a hundred volunteers (Stanford reports 111; the groups that were finally analysed add up to 108) and assigned them at random to one of four practices. Each was done for five minutes a day, for a month.
Three of the groups did controlled breathing. The first did cyclic sighing, which is the physiological sigh repeated rhythmically, with the long exhale emphasised. The second did box breathing, where you breathe in, hold, breathe out and hold again, each for the same count. The third did cyclic hyperventilation, a fast, deliberate over-breathing pattern followed by a hold. The fourth group was the comparison, and they did mindfulness meditation, which means paying steady, non-judging attention to the present moment. Everyone completed questionnaires about their mood and anxiety, and the researchers also tracked how quickly people breathed at rest.
The headline is that every group improved. All four reported better mood and lower anxiety over the month. That is worth pausing on, because it means that five quiet minutes a day, whichever kind you choose, was not wasted time for anyone in the study.
But the people doing cyclic sighing came out ahead. They gained the most in mood, and their resting breathing rate fell, which suggests the body was quietly lowering its own baseline. The difference between cyclic sighing and mindfulness reached statistical significance (P < .05), which is the researchers’ way of saying the gap was unlikely to be chance. For the controlled-breathing groups, the average improvement in positive affect, meaning feelings such as energy, enthusiasm and calm, was around 1.91 points on the questionnaire used. That is a modest, measurable lift, not a transformation, and it is best read as an average across a group rather than a promise for any one person. Resting heart rate, interestingly, did not change in any of the groups.
It is a small result, honestly reported. But five minutes a day is a small ask, and it is one of the few mood tools that needs no appointment, no waiting list and no money.
Why a longer breath out seems to help
Here is the mechanism in plain terms. When you breathe in, your heart speeds up very slightly. When you breathe out, it slows. This is called respiratory sinus arrhythmia, and it is the reason your pulse rises and falls with your breath. Stretch the exhale and you spend longer in the slowing half of the cycle. Spiegel has described this as using the exhale to engage the parasympathetic nervous system, the part of your body’s automatic wiring that handles rest and recovery.
The second, smaller inhale is the part people find most curious. A popular explanation, drawn mostly from laboratory and animal work, is that when you are stressed and breathing shallowly, some of the tiny air sacs in your lungs, called alveoli, partly collapse, and a second sip of air helps open them again so the long exhale can clear carbon dioxide more efficiently. It is a plausible account. It was not tested in this study, so it is best held as a reasonable idea rather than a settled fact.
What matters more is the practical point. You cannot tell your heart to slow down. You can tell your breath to get longer, and your heart tends to follow. Breathing is one of the very few body systems that runs on its own and also lets you take the controls.
That matters when anxiety starts to loop. You notice your chest tightening, and your mind adds, this must be really bad, and the alarm gets louder. A long, slow exhale gives you something to do in that moment other than argue with your own thoughts.
Does one minute in a real moment help?
You may be wondering whether any of this survives contact with real life. It is a fair question. The Stanford volunteers practised on a schedule, in calm conditions, for five minutes. Your difficult moments probably do not arrive on schedule. They arrive in a car park, in a corridor outside a meeting, or at the foot of the stairs with a form you have been avoiding.
That gap is exactly what a 2026 pilot study in the journal Anxiety, Stress & Coping set out to explore. It tested one-minute cyclic sighing against box breathing during real-life moments of anxiety. Its detailed results were not available to read at the time of writing, so this post makes no claim about what it found. What can be said is that researchers are now asking the question in everyday conditions and with one minute rather than five, which is the version of the question you actually care about.
It was a pilot, a first small look at whether an idea deserves a proper trial. Treat it as a sign of where the research is heading, not as evidence that the practice works in a crisis.
What this research cannot tell you
I want to slow down here, because hope without honesty helps nobody. These limits are not there to talk you out of trying this. They are there to protect you, so that you do not carry a headline into a conversation with your GP, your therapist or your family and expect it to bear more weight than it can.
The Stanford volunteers were healthy. They were not people with a diagnosed anxiety disorder, panic disorder or depression, so the study cannot tell you how the same practice would work for you if you are. Sara Lazar, a Harvard neuroscientist who commented on the work, described it as “just one study with a pretty small sample size”, and that is a fair summary. The benefit was modest. And the comparison group, mindfulness, improved too, so nobody should read this as breathing beating other approaches. It is one tool among several, not a treatment.
Notice, too, who was not in the study. If you have ADHD (attention-deficit hyperactivity disorder), the researchers did not test this on you. If you are autistic, the same is true. Applying it to your own brain is an extension of the findings, not something they showed, and it is best treated as a reasonable thing to try rather than a promise.
Some people also find that slow, deliberate breathing makes them more aware of their body and more anxious, not less. If that happens, it is a real response and not a failure of technique. Stop. Try something else, such as walking, pressing your feet into the floor, or naming five things you can see, and mention it to a clinician if you have one.
And if you are waiting for an assessment, newly diagnosed, or holding a letter that made your chest tighten before you had opened it, this is not a substitute for any of the help you are owed. It is something to do with your hands, in a manner of speaking, while you wait for that help to arrive.
How to try the physiological sigh
The practical part takes a minute to learn and needs no equipment. Start by sitting or standing somewhere you will not be interrupted, with your shoulders loose.
Breathe in through your nose until your lungs feel mostly full. Then take a second, shorter sip of air through your nose, on top of the first, to fill the last of the space. Now let it all out slowly through your mouth, as if you were fogging a window or sighing with relief, until you feel empty. Aim for the exhale to take longer than both inhales put together.
That is one round. Repeat it for a minute or so, which is perhaps five or six rounds, and then let your breathing return to normal. In the Stanford study the practice ran for five minutes a day, so if you like it, that is a sensible target for a daily habit. In a hard moment, three or four rounds is a good start.
Go gently. If you feel dizzy or light-headed, breathe normally and try again later with smaller breaths. You are not trying to force anything. You are trying to make the out-breath unhurried.
Where you do it matters as much as how. Choose three places in advance: standing at the kettle, in the car before you turn the engine off, in the lift at work. Tie the breath to the place and it stops being something you have to remember in the middle of a bad moment. Try it once now, while nothing is wrong, so your body knows the shape of it before it needs it.
Which of those three places would you pick first?
A small habit with an honest ceiling
A breathing exercise will not fix a job that is wearing you down, a bill you cannot pay, or a mind that has been anxious for years. What it can do is lower the volume, for a minute, so that you can think about the next thing clearly. That is a smaller promise than most wellness advice makes. It is also the one the research supports.
It costs you nothing. There is no app to download, no subscription, no ten-week course. Your body already knows this breath, and the evidence so far suggests that practising it on purpose, in small amounts and regularly, is worth a minute of your day.
Tonight, before you reach for your phone, lift the kettle off the heat. Two in, one long out. See what changes, and tell someone you trust if it helps.
Source: Balban, M. Y., Neri, E., Kogon, M. M., Weed, L., Nouriani, B., Jo, B., Holl, G., Zeitzer, J. M., Spiegel, D. & Huberman, A. D. (2023). “Brief structured respiration practices enhance mood and reduce physiological arousal.” Cell Reports Medicine, published 17 January 2023 (Stanford University School of Medicine); participant numbers as reported by Stanford and by MDedge; comment from Sara Lazar (Harvard) as quoted in press coverage. Also: a 2026 pilot study of one-minute cyclic sighing versus box breathing in real-life moments of anxiety, Anxiety, Stress & Coping. This article is for information and is not a substitute for medical advice.
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