The research behind the breathing
Neshi paces breathing patterns that researchers have studied. This page sets out what those studies found, how strong the evidence is for each pattern, and what none of it claims.
Why slowing the breath does anything at all
Breathing is unusual among body functions in that it runs automatically but can also be taken over deliberately. That makes it a rare direct handle on the autonomic nervous system, the part of you that governs heart rate and the stress response without asking permission.
When you slow your breathing to roughly six breaths a minute, heart rate begins to swing in time with it, rising on the inhale and falling on the exhale. At that pace the swings reach their largest amplitude, an effect known as resonance. A 2018 systematic review of slow breathing research found consistent associations with increased heart rate variability and shifts in autonomic balance, alongside reports of reduced arousal and improved mood [2].
Exhale length matters more than total breath volume. A longer exhale than inhale is associated with greater parasympathetic activity, which is the branch of the nervous system responsible for settling rather than mobilising. This is why most of the patterns in Neshi spend longer breathing out than in.
The patterns, and how well supported each one is
Cyclic sighing Randomised trial
Double inhale through the nose, then a long slow exhale. Neshi uses about 2.4 seconds in and 6.6 seconds out.
This has the best evidence of any pattern in the app. A randomised controlled trial at Stanford, published in Cell Reports Medicine in 2023, assigned 108 participants to five minutes a day of one of three breathing practices or of mindfulness meditation, for one month [1]. Cyclic sighing produced the greatest improvement in mood and the largest reduction in respiratory rate, outperforming both the other breathing patterns and mindfulness meditation.
Worth being precise about the finding: the clear results were in self reported mood and in breathing rate. The trial did not establish that cyclic sighing improves heart rate variability more than the alternatives.
Coherent breathing Well studied
Equal in and out at about 5.5 seconds each, roughly 5.5 breaths a minute.
Breathing at close to six breaths a minute sits at the resonance frequency of the baroreflex, the loop that regulates blood pressure. Paced breathing at this rate reliably produces the largest heart rate oscillations, and the 2018 review found slow breathing at these rates associated with higher heart rate variability and lower physiological arousal [2].
Individual resonance frequency varies, roughly between 4.5 and 6.5 breaths a minute, so 5.5 is a sensible default rather than a precise personal figure.
Box breathing Mechanism and practice
Four seconds each of inhale, hold, exhale, hold.
Box breathing was one of the three patterns tested in the Stanford trial [1]. It improved mood over the month, though less than cyclic sighing. Its equal phases keep the breath at a slow, regular rate without an exhale bias, which fits its reputation as a pattern for staying calm and alert rather than for winding down.
4-7-8 breathing Mechanism and practice
Inhale four seconds, hold seven, exhale eight.
This pattern is popular for winding down and has a plausible mechanism, since it combines a long breath hold with an exhale twice the length of the inhale, both of which push toward the settling side of the nervous system [2]. It has not been tested in a large trial of its own, so treat it as a sensible application of the slow breathing evidence rather than a separately proven protocol.
Diaphragmatic, pursed lip and alternate nostril Mechanism and practice
Diaphragmatic breathing, meaning breathing into the belly rather than the upper chest, is the foundation the other patterns rest on and is widely used in clinical breathing instruction. Pursed lip breathing slows the exhale by adding resistance. Alternate nostril breathing comes from yogic practice and is used to settle attention. All three are covered by the general slow breathing literature [2] rather than by dedicated trials at the scale of the Stanford study.
What this evidence does not say
Neshi is a general wellness app. It is not a medical device, it does not diagnose anything, and it does not treat any condition. The studies above measured things like mood, breathing rate and heart rate variability in mostly healthy adults over short periods. They do not show that breathing exercises replace medical care, and nothing here should be read as clinical advice. If you are dealing with a health condition, including anxiety or a breathing disorder, talk to a doctor. If a pattern makes you dizzy or uncomfortable, stop and breathe normally.
References
- Balban, M. Y., Neri, E., Kogon, M. M., Weed, L., Nouriani, B., Jo, B., Holl, G., Zeitzer, J. M., Spiegel, D., and Huberman, A. D. (2023). Brief structured respiration practices enhance mood and reduce physiological arousal. Cell Reports Medicine, 4(1), 100895. PubMed
- Zaccaro, A., Piarulli, A., Laurino, M., Garbella, E., Menicucci, D., Neri, B., and Gemignani, A. (2018). How breath control can change your life: a systematic review on psycho physiological correlates of slow breathing. Frontiers in Human Neuroscience, 12, 353. Full text