Anuloma Viloma TimerMental Health Awareness Month starts today. A 2025 trial put breathwork at a Cohen’s d of 1.44 for anxiety. That is a large effect size by every benchmark statisticians use, larger than most antidepressants register in their own pivotal trials, and the trial that produced it is still in the early window of wellness-media coverage.
The paper, “Efficacy of online conscious connected breathwork in reducing symptoms of anxiety: a randomized waitlist control trial,” appeared in the Journal of Affective Disorders in late 2025 and is now circulating widely as Mental Health Awareness Month opens. It is worth reading the methodology before reading the headline, because the result hangs on a few choices that are easy to miss.
What the trial actually measured
The researchers recruited 107 adults (80 percent women, mean age 41) who reported anxiety symptoms above a screening threshold. The intervention was six weekly 90-minute group sessions of conscious connected breathwork delivered entirely online. The control group was a waitlist condition: same screenings, same outcome measures, no intervention until after the study window closed.
The primary outcome was a validated anxiety scale measured before the intervention and after the six-week window. The intervention group showed a statistically significant reduction in anxiety scores at p less than .001, and the standardised mean difference between intervention and control reached a Cohen’s d of 1.44.
That number is the one to sit with. A Cohen’s d of 0.2 is generally called a small effect. A d of 0.5 is moderate. A d of 0.8 is large. A d of 1.44 is what researchers usually describe as a very large effect, the kind of result that almost never appears in psychiatric trials of medication. The most commonly prescribed SSRIs typically post effect sizes in the 0.3 to 0.4 range against placebo in their pivotal trials. A breathwork intervention reaching 1.44 against a waitlist control is not a small finding.
Why the effect is biologically plausible
The mechanism the authors cite is the same one that has appeared in every other rigorous breathwork study published this decade. Prolonged conscious breathing, particularly slow nasal breathing with extended exhales, stimulates the vagus nerve. Vagal stimulation shifts the autonomic balance from sympathetic dominance (the fight-or-flight register that anxious bodies live in) toward parasympathetic recovery (the register that rest, digestion, and emotional regulation depend on). The shift is measurable in heart rate variability, in cortisol, and in subjective state.
The authors also cite a neurobiological component. Sustained slow breathing increases cortical blood flow to brain regions that the anxious brain tends to under-use, including the prefrontal cortex and the insula. The same regions are repeatedly implicated in emotional regulation and interoception. The trial’s qualitative interviews suggest a third mechanism that quantitative outcomes do not capture: an embodied, nonverbal kind of processing that happens during a long breathwork session, where material the conscious mind has been ignoring surfaces and resolves without ever becoming a sentence.
Why this matters for alternate nostril breathing
Conscious connected breathwork is not the same protocol as alternate nostril breathing. The 2025 trial used continuous circular breathing through both nostrils for sessions an hour and a half long. Anuloma Viloma is structurally different: a controlled alternation between nostrils, slower in pace, designed for shorter daily sessions of 5 to 20 minutes.
The mechanism, however, overlaps substantially. Both protocols depend on slow nasal breathing for the vagal effect. Both rely on extended exhales to produce the autonomic shift. Both operate in roughly the same resonance-frequency range that other breathwork research has identified as the optimum for HRV gain. What alternate nostril breathing adds is a structural rhythm that beginners can learn and repeat without the supervision of a facilitator. That is not a small advantage when the goal is daily practice rather than a six-week course.
If a single protocol could reach a Cohen’s d of 1.44 for anxiety in six 90-minute sessions, the daily five-minute version of the same family of techniques is unlikely to be a wasted investment.
What this changes about the month ahead
Mental Health Awareness Month tends to drift between two registers. One is heavy: campaigns about crisis lines and stigma reduction, both important and not the subject of this post. The other is light to the point of being unhelpful: vague suggestions about self-care that translate to nothing measurable and nothing repeatable. The 2025 trial sits in a third register, the one that actually moves a body from anxious to regulated. It is the register where a specific, structured, nonpharmacological intervention produces a measurable result, and the act of doing it daily is the thing that compounds.
If you are reading this in May with a felt sense of low-grade chronic anxiety that has not responded to anything you have tried, a five-minute alternate nostril breathing practice is not going to feel like much on day one. It will feel like nothing on day two. By day fourteen, the floor of the autonomic system is somewhere different. That is the entire mechanism the trial measured, scaled into a daily habit.
The Journal of Affective Disorders trial is the cleanest piece of evidence the literature offers right now. Breathwork is not a soft suggestion. It is a measured intervention with a Cohen’s d that most clinical psychologists would consider large. The five-minute version is the one you can actually do.
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References
- Efficacy of online conscious connected breathwork in reducing symptoms of anxiety: a randomized waitlist control trial. Journal of Affective Disorders, 2025. https://www.sciencedirect.com/science/article/abs/pii/S0165032725020075
- The A52 Breath Method: A Narrative Review of Breathwork for Mental Health and Stress Resilience. PMC, 2025/2026. https://pmc.ncbi.nlm.nih.gov/articles/PMC12341363/
- Nadi Shuddhi Pranayama and HRV in Young Adults. PMC12331837. https://pmc.ncbi.nlm.nih.gov/articles/PMC12331837/