Which breathing exercise is best for a panic moment or sudden stress?

For an acute spike, the simplest options are usually the most reliable: extended-exhale breathing (breathe in for about 4, out for about 6–8) or the physiological sigh (two breaths in through the nose, then a long slow breath out). Both lean on the same idea — a longer out-breath than in-breath shifts you toward the body's calming response. The physiological sigh has the single best controlled trial of the techniques on this page: a 2023 Stanford study found five minutes a day of cyclic sighing improved mood and slowed breathing rate more than the same time spent on mindfulness ([Balban et al., Cell Reports Medicine 2023](https://pmc.ncbi.nlm.nih.gov/articles/PMC9873947/)). Importantly, if you are mid-panic, avoid long breath-holds — the air-hunger from holding can make panic worse. Skip box breathing and 4-7-8 in that moment and use a no-hold pattern.

Is 'coherent breathing' actually better than just breathing slowly?

Breathing at around six breaths a minute (0.1 Hz) lines up with your body's natural cardiovascular rhythm and produces the largest swing in heart rate with each breath — this is the 'resonance frequency,' and it reliably increases heart-rate variability and can acutely lower blood pressure ([Shaffer & Meehan 2020](https://www.frontiersin.org/journals/neuroscience/articles/10.3389/fnins.2020.570400/full); [Laborde et al. 2022](https://www.sciencedirect.com/science/article/abs/pii/S0149763422002007)). What the evidence does *not* show is that painstakingly tuning to your exact personal rate gives better real-world results than simply breathing slowly and evenly — the field's own key reference says clinical superiority of precise tuning is not established ([Shaffer & Meehan 2020](https://www.frontiersin.org/journals/neuroscience/articles/10.3389/fnins.2020.570400/full)). So: aim for slow and even, around 5–6 breaths a minute, and don't overthink the exact number.

Can breathing exercises lower my blood pressure?

Slow breathing can lower blood pressure in the short term. Meta-analyses report a small immediate drop in healthy adults and a larger reduction in people with high blood pressure ([Shao et al. 2024](https://link.springer.com/article/10.1007/s12671-023-02294-2); [Cheng et al. 2026](https://pmc.ncbi.nlm.nih.gov/articles/PMC13093598/)). But these trials are mostly short, hard to blind, and the larger figures are at the optimistic end of the literature. Breathing is a reasonable, free, low-risk addition to the things that genuinely move blood pressure — not a replacement for them, and not a reason to change or stop blood-pressure medicine. If you have high blood pressure, keep working with your GP and keep taking what's prescribed.

Does it matter whether I breathe through my nose or mouth?

Nasal breathing is a sensible default — the nose filters, warms and humidifies air, and many of these techniques are taught nose-in, nose-or-mouth-out. That said, the head-to-head evidence on whether nasal versus mouth breathing changes the calming effect of slow breathing is thin, so this is more reasonable practice than proven fact. The part that clearly matters is the pace and the longer out-breath, not which opening you use. If your nose is blocked, breathing slowly through the mouth is fine.

Is breathwork ever dangerous?

Gentle slow breathing is safe for most people. The real danger is a different style of breathwork: forceful, rapid over-breathing (hyperventilation) followed by holding your breath — especially in or near water. Over-breathing blows off carbon dioxide, and it is the rise in carbon dioxide, not a fall in oxygen, that normally drives the urge to breathe. Remove that trigger and you can black out before your body warns you — this is the mechanism of shallow-water blackout, which can be fatal ([StatPearls / NCBI](https://www.ncbi.nlm.nih.gov/books/NBK554620/)). Never do hyperventilation-style or breath-hold breathwork in a pool, bath, or open water. Also check with your GP before starting if you have a heart or lung condition, epilepsy, or are pregnant, or if breath-focus tends to trigger your anxiety.

Stress and anxiety (self-management)

Breathing techniques: what the evidence shows, and when to use which

By Dr HB Lo, FACRRM Reviewed 5 June 2026 7 min read

Slow breathing at about six breaths a minute is the thread behind every method here — it nudges the body's calming (parasympathetic) system and lifts heart-rate variability.

Strongest evidence: coherent breathing (~5.5–6/min) and the physiological sigh (double in-breath, long out-breath). Box breathing and 4-7-8 are popular but less tested. Effects are mostly short-term; this is a wellbeing practice, not a treatment.

Breathe gently and stop if you feel dizzy. Never mix forceful breathing or breath-holding with water. If anxiety is overwhelming, call Lifeline 13 11 14 or Beyond Blue 1300 22 4636.

Almost every “breathing technique” you’ll see online is a variation on one simple idea: slow your breathing to about six breaths a minute, and make the out-breath unhurried. This page explains why that works, walks through the five methods in the drhblo breathing tool, and — most usefully — tells you when to reach for which, with an honest note on how strong the evidence actually is for each.

A grounding point first: breathing exercises are a general wellbeing practice, not a medical treatment. They are not a substitute for advice, therapy or medication for any diagnosed condition. The effects measured in studies are mostly short-term. With that framing, the evidence is genuinely interesting.

How slow breathing works

When you breathe slowly and evenly at around six breaths a minute (0.1 Hz), your breathing rhythm lines up with the natural rhythm of your heart rate and blood pressure. At this “resonance frequency” the heart-rate swing with each breath is amplified several-fold, which is why slow breathing reliably increases heart-rate variability — a marker of a flexible, well-regulated nervous system — and stimulates the baroreflex, the loop that buffers your blood pressure (Shaffer & Meehan, Frontiers in Neuroscience 2020).

The leading explanation for the calming feeling is the longer out-breath. The working model is that a long, slow exhalation increases the activity of the vagus nerve — the main nerve of the body’s “rest and digest” (parasympathetic) system — tipping you toward a calmer state (Noble & Hochman, Frontiers in Physiology 2019). It’s worth being precise here: slow breathing increases vagal activity during practice; it isn’t proven to permanently raise your resting “vagal tone,” and parts of this mechanism are still a working hypothesis rather than settled fact.

Quick translation: slow down, and breathe out for longer than you breathe in. Everything below is a way of doing exactly that.

The five methods

Coherent (resonance) breathing — ~5.5–6 breaths a minute

What it is: smooth, equal breaths, roughly 5.5 seconds in and 5.5 seconds out, no holds.

Evidence: this is the best-understood method. A large systematic review found voluntary slow breathing at ~6 breaths a minute reliably raises heart-rate variability (Laborde et al., Neuroscience & Biobehavioral Reviews 2022), and meta-analyses show acute blood-pressure lowering — small in healthy adults, larger in people with hypertension (Shao et al. 2024; Cheng et al. 2026). Heart-rate-variability biofeedback (essentially trained resonance breathing) has a large effect on self-reported stress and anxiety, though on short-term, self-report measures (Goessl et al., Psychological Medicine 2017).

Best for: a daily general-relaxation practice, and the go-to if you want the option with the deepest physiological evidence.

Extended-exhale breathing — out-breath longer than in-breath

What it is: breathe in for about 4, out for about 8 — no holds. The defining feature is simply that the exhalation is longer than the inhalation.

Evidence: it shares the same vagal-on-the-out-breath mechanism as coherent breathing and cyclic sighing (Noble & Hochman 2019), and the long exhale is the element common to the best-tested techniques.

Best for: the simplest moment-to-moment way to down-shift — and a gentle alternative if breath-holds feel uncomfortable.

Physiological sigh (cyclic sighing) — double in-breath, long out-breath

What it is: two breaths in through the nose (a full one, then a small top-up), followed by a long, slow breath out.

Evidence: this has the single strongest trial of the five. A 28-day randomised study of 100 adults found five minutes a day of cyclic sighing improved mood and slowed resting breathing rate more than the same time spent on mindfulness meditation (Balban et al., Cell Reports Medicine 2023). It’s one good trial in a young, healthy sample — promising rather than the last word.

Best for: a fast reset when stress or anxiety is rising — likely the best evidenced option for acute relief.

Box breathing — 4-4-4-4

What it is: in for 4, hold for 4, out for 4, hold for 4. Popular with the military and first responders for staying composed under pressure.

Evidence: weaker and indirect. In the one head-to-head trial above, box breathing was included but was not the leading arm (Balban et al. 2023). Its reputation rests more on widespread use and plausible mechanism than on strong trial data.

Best for: focus and composure before a demanding task — if you like the structure. Skip the holds if you’re feeling panicky.

4-7-8 breathing — in 4, hold 7, out 8

What it is: a short breath in, a long hold, then a long slow breath out. Widely promoted as a sleep aid.

Evidence: the weakest of the five — no strong primary trial specifically tests 4-7-8. It’s plausible by mechanism (a long exhale and a slowed overall rate), but should be treated as low-evidence rather than proven.

Best for: a wind-down before sleep, if you find it pleasant — on the understanding the evidence is thin. The 7-count hold is long; shorten it if you feel breathless, and avoid holds if you’re anxious.

When to use which — quick reference

Method	Simple pattern	Reach for it when…	Evidence
Coherent / resonance	~5.5 in · ~5.5 out (no holds)	you want a daily calming practice; HRV / blood pressure	Strongest (mechanism, HRV, BP)
Extended exhale	4 in · 8 out (no holds)	you need a simple in-the-moment down-shift	Moderate (shared mechanism)
Physiological sigh	2 in (nose) · long out	stress or anxiety is spiking and you want fast relief	Best single trial (Balban 2023)
Box breathing	4 in · 4 hold · 4 out · 4 hold	focus / composure before a task	Weak / indirect
4-7-8	4 in · 7 hold · 8 out	winding down before sleep	Low (mechanism only)

One-line version: for calm and panic, use a no-hold, long-exhale pattern (physiological sigh or extended exhale); for a daily practice, use coherent breathing; box and 4-7-8 are fine if you enjoy them, but lean on the long out-breath, and drop the holds if anxiety is high.

Is it safe? Who should check with their GP first

Gentle slow breathing is safe for most people. Two cautions matter:

Don’t force it. Breathe gently — don’t drag in huge breaths. Stop and breathe normally if you feel dizzy, light-headed or tingly; that’s usually a sign you’re over-breathing.
Never mix forceful breathing or breath-holding with water. Rapid over-breathing followed by a breath-hold — in a pool, bath or open water — can cause you to black out without warning. The urge to breathe is driven by rising carbon dioxide, not falling oxygen; over-breathing removes that warning, so oxygen can drop to dangerous levels first. This is the mechanism of shallow-water blackout, which can be fatal (StatPearls / NCBI Bookshelf).

Check with your GP before starting if you have a heart or lung condition, epilepsy or a seizure disorder, or are pregnant — and if breath-focus tends to set off your anxiety, choose the gentle no-hold patterns and stop if it feels worse. General relaxation breathing is not a treatment for any diagnosed condition, and shouldn’t replace prescribed care. For everyday consumer guidance, the Better Health Channel has a plain-language overview.

If you are distressed and need to talk to someone now, call Lifeline 13 11 14 or Beyond Blue 1300 22 4636. If you are unwell and unsure what to do, call healthdirect 1800 022 222 (free, 24 hours). In an emergency call 000.

Try it

The free drhblo breathing tool guides you through all five patterns with a visual wave, optional sound and gentle vibration cues — no sign-up, and it runs entirely on your device.

Sources cited

Frequently asked questions

Which breathing exercise is best for a panic moment or sudden stress?

For an acute spike, the simplest options are usually the most reliable: extended-exhale breathing (breathe in for about 4, out for about 6–8) or the physiological sigh (two breaths in through the nose, then a long slow breath out). Both lean on the same idea — a longer out-breath than in-breath shifts you toward the body's calming response. The physiological sigh has the single best controlled trial of the techniques on this page: a 2023 Stanford study found five minutes a day of cyclic sighing improved mood and slowed breathing rate more than the same time spent on mindfulness ([Balban et al., Cell Reports Medicine 2023](https://pmc.ncbi.nlm.nih.gov/articles/PMC9873947/)). Importantly, if you are mid-panic, avoid long breath-holds — the air-hunger from holding can make panic worse. Skip box breathing and 4-7-8 in that moment and use a no-hold pattern.
Is 'coherent breathing' actually better than just breathing slowly?

Breathing at around six breaths a minute (0.1 Hz) lines up with your body's natural cardiovascular rhythm and produces the largest swing in heart rate with each breath — this is the 'resonance frequency,' and it reliably increases heart-rate variability and can acutely lower blood pressure ([Shaffer & Meehan 2020](https://www.frontiersin.org/journals/neuroscience/articles/10.3389/fnins.2020.570400/full); [Laborde et al. 2022](https://www.sciencedirect.com/science/article/abs/pii/S0149763422002007)). What the evidence does *not* show is that painstakingly tuning to your exact personal rate gives better real-world results than simply breathing slowly and evenly — the field's own key reference says clinical superiority of precise tuning is not established ([Shaffer & Meehan 2020](https://www.frontiersin.org/journals/neuroscience/articles/10.3389/fnins.2020.570400/full)). So: aim for slow and even, around 5–6 breaths a minute, and don't overthink the exact number.
Can breathing exercises lower my blood pressure?

Slow breathing can lower blood pressure in the short term. Meta-analyses report a small immediate drop in healthy adults and a larger reduction in people with high blood pressure ([Shao et al. 2024](https://link.springer.com/article/10.1007/s12671-023-02294-2); [Cheng et al. 2026](https://pmc.ncbi.nlm.nih.gov/articles/PMC13093598/)). But these trials are mostly short, hard to blind, and the larger figures are at the optimistic end of the literature. Breathing is a reasonable, free, low-risk addition to the things that genuinely move blood pressure — not a replacement for them, and not a reason to change or stop blood-pressure medicine. If you have high blood pressure, keep working with your GP and keep taking what's prescribed.
Does it matter whether I breathe through my nose or mouth?

Nasal breathing is a sensible default — the nose filters, warms and humidifies air, and many of these techniques are taught nose-in, nose-or-mouth-out. That said, the head-to-head evidence on whether nasal versus mouth breathing changes the calming effect of slow breathing is thin, so this is more reasonable practice than proven fact. The part that clearly matters is the pace and the longer out-breath, not which opening you use. If your nose is blocked, breathing slowly through the mouth is fine.
Is breathwork ever dangerous?

Gentle slow breathing is safe for most people. The real danger is a different style of breathwork: forceful, rapid over-breathing (hyperventilation) followed by holding your breath — especially in or near water. Over-breathing blows off carbon dioxide, and it is the rise in carbon dioxide, not a fall in oxygen, that normally drives the urge to breathe. Remove that trigger and you can black out before your body warns you — this is the mechanism of shallow-water blackout, which can be fatal ([StatPearls / NCBI](https://www.ncbi.nlm.nih.gov/books/NBK554620/)). Never do hyperventilation-style or breath-hold breathwork in a pool, bath, or open water. Also check with your GP before starting if you have a heart or lung condition, epilepsy, or are pregnant, or if breath-focus tends to trigger your anxiety.

Source quality

Sources grouped by evidence tier. AU primary tier first; international where AU is silent or lagging; named-author reconstruction where guidelines have not yet caught up. How tiers work.