What 4-7-8 breathing is
4-7-8 breathing is a slow breathing pattern. You breathe in through your nose for 4 seconds. You hold for 7 seconds. You breathe out for 8 seconds. One full cycle takes 19 seconds. That works out to about 3.2 breaths a minute. Normal resting breathing for adults is about 12 to 20 breaths a minute [Russo et al. 2017]. So 4-7-8 is much slower than your usual pace.
The long exhale and the hold are the point. At around six breaths a minute, breathing and the blood-pressure rhythm of the baroreflex line up. That is why heart-rate swings grow [Russo, Santarelli & O'Rourke 2017]. 4-7-8 sits below six breaths a minute, with an exhale twice as long as the inhale. That shape is what makes it feel different from a steady in-and-out breath.
Dr. Andrew Weil popularised 4-7-8 as a relaxation and sleep exercise. He suggests four cycles at a time to begin. The pattern is easy to remember, which is likely why it spread. You do not need a device to count it.
What the research says
Evidence specific to 4-7-8 is thin. No large trial has tested this exact pattern against a control. The general slow-breathing evidence applies instead, because 4-7-8 is slow breathing with a long exhale and a hold.
A 2018 systematic review of 15 studies in healthy people found slow breathing under 10 breaths a minute was associated with increased HRV and respiratory sinus arrhythmia. It was also associated with EEG changes (more alpha, less theta) and reports of increased comfort, relaxation, pleasantness, vigor and alertness. The same review reported reduced arousal, anxiety, depression, anger and confusion. The review is of healthy subjects and the studies are small [Zaccaro et al. 2018].
A 2020 meta-analysis of 58 randomized controlled studies of HRV biofeedback found a small to moderate effect in its favour. The largest effects were for anxiety, depression, anger and athletic or artistic performance. The smallest were for PTSD, sleep and quality of life, each based on a small number of studies. The authors call it useful as a complementary approach and say further research is needed for particular uses [Lehrer et al. 2020].
A 2017 study at Brigham Young University compared three groups for 15 minutes: breathing at the individual resonance frequency, breathing one breath a minute faster, and sitting quietly. The resonance group reported higher positive mood than the other two. They showed a higher LF/HF HRV ratio than the control group. They also had lower systolic blood pressure during a stressful mental task afterwards [Steffen et al. 2017].
These are associations from small or moderate studies, not proof. Individual results vary. This site is educational and not medical advice.
How to practise 4-7-8
The 7-second hold is hard at first. Most people can do a 4-second inhale and an 8-second exhale before they can hold for 7. Build up over days. Start with a shorter hold, such as 4 seconds, and keep the inhale and exhale the same. Once that feels easy, add a second to the hold every few days until you reach 7.
Weil suggests four cycles at a time to begin. That is about 76 seconds of practice. You can do one set in the morning and one before bed. When four cycles feel comfortable, add a cycle at a time. Twenty minutes a day is the practice dose in Leah Lagos's program and in most HRV biofeedback studies [Lehrer et al. 2020].
Breathe through your nose where possible. Keep the breath light and unforced. Over-breathing causes light-headedness. Sit or lie comfortably. Stop if you feel dizzy.
Here is a worked example. Suppose you want to practise at 4-7-8 for 10 minutes. Each cycle is 19 seconds. Ten minutes is 600 seconds. 600 divided by 19 is about 31.5 cycles. So you would complete about 31 full cycles in 10 minutes. If you start with four cycles, that is 76 seconds. You can build from there.
If you want a different slow pattern, try the box breathing timer (4-4-4-4, about 3.75 breaths a minute) or the coherent breathing page (about 5 to 6 breaths a minute with equal inhale and exhale). To find your own best rate, use the resonance frequency test. The breathing pacer can guide any pace you choose.
Who should check with a clinician first
Anyone who is pregnant, has a heart or lung condition, a history of fainting, panic disorder, or epilepsy, or is being treated for a mental health condition should check with a clinician first. Slow breathing can lower blood pressure and heart rate. People on medication for either should ask their clinician. Nothing on this site is medical advice, a diagnosis or a treatment.
If you want to measure your HRV while you practise, you need a Bluetooth chest strap (for example the Polar H10) and an HRV app (for example Elite HRV, HRV4Biofeedback or Kubios). Wrist wearables measure HRV overnight and are not suited to a two-minute paced test. The site sells no device and has no affiliate relationship with device makers. See HRV chest strap for more.