Anuloma Viloma TimerCyclic sighing. Cardiac coherence. 4-7-8. Box breathing. Vagus toning.
Five different names you have probably read in the last twelve months, each presented as a discrete technique with its own founder, its own protocol card, its own podcast cycle. Four of them were popularised in the last fifty years. One was popularised in the last five. All of them describe slow, paced, nasal-led breathing inside a narrow rate band. All of them produce results because of the same physiological mechanism. And all of them are downstream of a practice that was codified in writing in India more than 2,500 years ago. Its name is pranayama. The specific structured form most of these rebrands keep gesturing toward is nadi shodhana, also called anuloma viloma.
This piece is the receipt.
What Each Modern Name Actually Is
Cyclic sighing. Popularised in 2023 by a Stanford randomised trial that compared it to meditation and to box breathing. The pattern is a long nasal inhale followed by a second short top-up inhale, then a long extended nasal exhale. The mechanism the paper credited was extended exhalation activating the parasympathetic nervous system through vagal afferents. That is the same mechanism a slow exhale in pranayama has always activated, for the same reason.
Cardiac coherence. Popularised in the 1990s by HeartMath researchers and adopted by the French health ministry in the 2010s. The protocol is six breaths per minute, sustained for five minutes, three times a day. Six breaths per minute is roughly a five-second inhale and a five-second exhale, the rate that maximises heart rate variability in the high-frequency band. The 2025 PubMed scoping review on slow breathing and HRV converged on the same number: 5.5 to 6 breaths per minute.
4-7-8 breathing. Popularised in the 2010s by Andrew Weil. Four-second inhale, seven-second hold, eight-second exhale, through the nose, repeated four times. It is a specific ratio of a much older pattern: ratio-controlled nasal breathing with a held phase between inhale and exhale. The held phase has a Sanskrit name. It is called kumbhaka.
Box breathing. Popularised in the 1980s by US Navy SEAL trainers and in the 2010s by Mark Divine and others. Four-second inhale, four-second hold, four-second exhale, four-second hold. Equal-ratio nasal breathing with both an inhalation hold (antara kumbhaka) and an exhalation hold (bahya kumbhaka). Both holds, again, are not new. They were named in writing centuries before any Navy existed.
Vagus toning. A 2025 wellness umbrella term covering everything from cold plunge to humming to chanting to slow breathing. The slow-breathing component is the most evidence-rich of the bunch. The MDPI 2025 head-to-head trial in Journal of Clinical Medicine put deep nasal breathing against transcutaneous auricular vagus nerve stimulation (a $300 device class) and the breathing matched or beat it on multiple parasympathetic HRV parameters.
Five names. One mechanism. Slow, paced, nasal breathing inside a 5 to 7 breaths-per-minute window, with optional held phases.
What Pranayama Actually Codified
The Hatha Yoga Pradipika (15th century) and the Yoga Sutras of Patanjali (compiled roughly 2,500 years ago, traditions place its origins earlier) wrote down structured breath practice in detail that maps cleanly onto every protocol above. The relevant Sanskrit vocabulary, with the rough modern translation:
- Puraka is the inhale.
- Rechaka is the exhale.
- Kumbhaka is the held breath. Antara kumbhaka is the hold after the inhale (4-7-8 lives here). Bahya kumbhaka is the hold after the exhale (the second pause in box breathing lives here).
- Nadi shodhana is the alternated, structured form: inhale through one nostril, hold, exhale through the other, hold, repeat. It is also called anuloma viloma. The Sanskrit name nadi shodhana literally translates as “channel cleaning.”
A traditional nadi shodhana session paced at one full nostril cycle every ten seconds, with brief holds, is by construction a 5 to 7 breaths-per-minute, ratio-controlled, nasal-only breath practice with kumbhaka phases. It is structurally the union of cardiac coherence and 4-7-8 and box breathing, with the additional discipline of nostril alternation that the modern rebrands drop.
The 2025 PLOS One high-density EEG study on alternate nostril breathing confirmed the alternation matters. The paper found that alternated nostril breathing suppressed alpha and mu oscillations over central and parietal areas more strongly than left-nostril-only breathing, and increased frontal midline theta. Translated: the act of switching nostrils produces a measurable additional neurological effect on top of slow nasal breathing alone.
Cyclic sighing, cardiac coherence, 4-7-8, and box breathing all leave that effect on the table. Nadi shodhana keeps it.
Why the Renaming Keeps Happening
Three reasons, none of which are mysterious.
The first is that English wellness markets reward novelty. A protocol that is 2,500 years old does not get a podcast tour. A protocol invented by a researcher you can interview, named a year ago, does. The branding cycle is doing what branding cycles do.
The second is that the original Sanskrit terminology is unfamiliar enough that wellness publications quietly drop it. “Nadi shodhana” is harder to put on a magazine cover than “the 4-7-8 method.” That is a media-economics problem, not a science problem.
The third, more honest reason, is that the modern rebrands often genuinely simplify the practice. Box breathing is easier to teach in a tactical-medic course than full nadi shodhana with mudra and traditional pacing. Cardiac coherence is easier to prescribe in a French clinic than to walk a patient through Sanskrit. The simplifications work. They just are not new techniques. They are subsets of an older one.
What the Research Suggests for a Lay Reader
If you have already tried 4-7-8, box breathing, or cardiac coherence and felt them work, the takeaway is not that any of them are wrong. The takeaway is that they are smaller versions of a more complete practice. Adding the nostril alternation costs you nothing and the EEG evidence suggests it does measurable additional work.
If you have not tried any of them, the most parsimonious place to start is the original. Five seconds in through one nostril, two-second hold, five seconds out through the other, repeated for five minutes. That is the cadence the 2025 A52 Breath Method narrative review (Wiley Stress and Health, 465 articles screened) named clinically optimal for vagal tone, HRV, parasympathetic activity, and cortisol reduction. It is also functionally what nadi shodhana has always been.
A timer helps. Most people lose count around the third minute.
The App
Anuloma Viloma Timer is free on the App Store. No subscription necessary. The default pacing matches the 5-second inhale, 5-second exhale, 2-second hold cadence the research keeps converging on. The Apple Watch companion runs the same session on the wrist. The watch logs your resting heart rate before and after, so the experiment runs itself.
If you have been trying the rebrands one at a time, this is the original. The names will keep changing. The protocol does not.