Breathing Techniques Compared: What Head-to-Head Studies Show

What has actually been compared?

Box breathing, four-seven-eight, cyclic sighing and plain slow breathing are often presented as competing tools, each with its own promise. Very few studies have put them side by side. This page collects the direct comparisons that exist, says what each one found and in whom, and marks the questions nobody has tested. Almost every result below comes from a single study, so each is a lead rather than a settled answer.

Heart rate variability (HRV) is the beat-to-beat variation in the interval between heartbeats. Several of the studies measured it; others measured mood, anxiety, heart rate or pain. How breathing shapes HRV in general is explained on breathing and HRV.

Cyclic sighing or mindfulness meditation?

The largest direct comparison is a remote randomized trial of three daily five-minute breathing exercises, compared with the same amount of mindfulness meditation over one month [S1]. The three breathing exercises were cyclic sighing, which emphasizes long exhales; box breathing, with equal inhale, hold, exhale and hold; and cyclic hyperventilation with retention [S1]. Breathwork as a whole, and especially exhale-focused cyclic sighing, improved mood and lowered breathing rate more than meditation [S1]. In one RCT, then, cyclic sighing done for 5 minutes a day came out ahead of meditation. One author was an adviser to WHOOP, the wearable maker that donated the wrist straps used to record breathing and heart data. The abstract does not report statistics comparing the breathing styles with each other, so it does not show that cyclic sighing beat box breathing.

What seems to matter is the long exhale, not the sigh. In a laboratory protocol with 250 healthy college students, single deliberate sighs raised heart rate, blood pressure and low-frequency HRV — a pattern consistent with activation of the sympathetic, "fight or flight" branch [S2]. That does not contradict the trial: cyclic sighing is a repeated pattern built around slow, extended exhales, while a single sigh is a brief jolt. Slow breathing is associated with higher vagally mediated HRV; whether a longer exhale adds anything beyond slowing the breath is still debated. In a twelve-week trial in healthy adults, slow breathing with a longer exhale did not reduce stress more than slow breathing with an equal exhale [S6].

Box breathing or slow breathing after exercise?

In one study after interval training, breathing at six breaths per minute lowered heart rate more than box breathing. The crossover trial included 40 physically active university students, each doing three interval-training sessions on a spin bike [S3]. During recovery they used spontaneous breathing, box breathing (4 seconds each to breathe in, hold, breathe out and hold) or breathing at 6 breaths per minute (5 seconds in, 5 seconds out) [S3]. Heart rate after exercise was 164.65 bpm after box breathing and 154.77 bpm after breathing at 6 breaths per minute (Cohen's d = 0.907), and perceived exertion was 17.27 after box breathing and 15.25 after breathing at 6 breaths per minute (Borg scale) [S3]. Box breathing also showed a trend towards a slower return to resting heart rate, but that difference was not significant [S3]. The authors conclude that box breathing may add physiological and perceptual stress straight after hard intervals [S3].

The context matters. In a randomized trial with 62 cadets (44 men and 18 women) recovering from a maximal exercise test, both box breathing and cyclic sighing sped up the recovery of high-frequency HRV compared with breathing normally [S4]. That trial compared structured breathing with no technique, not box breathing with slow breathing, and it did not rank the two styles. More on recovery after training is on exercise and HRV.

Box breathing or a long exhale before stress?

In a randomized trial with 66 adults, 22 in each group, participants breathed normally, with a prolonged exhale or in a box pattern before a virtual version of a standard public-speaking and mental-arithmetic stress test [S5]. Both techniques blunted the rise in heart rate, state anxiety and salivary alpha-amylase, a marker of stress arousal, compared with normal breathing [S5]. Neither won: the two were equivalent. HRV, cortisol and cognitive performance were unchanged across all three conditions [S5]. That null result for HRV is part of the finding, not a footnote.

What is known about four-seven-eight breathing?

Four-seven-eight breathing means breathing in for a count of four, holding for seven and breathing out for eight. Three small studies tested it in different settings.

• Heart rate variability: not shown. In an analyst-blinded crossover study of 34 university students (19 men and 15 women), each doing three ten-minute conditions, a single session of four-seven-eight or alternate-nostril breathing did not change standard HRV measures [S7]. Its subjective effects depended on sex: four-seven-eight was associated with less stress and negative affect in women, alternate-nostril breathing with larger reductions in men [S7]. "Not shown" does not mean an effect is impossible; it means this one study did not find it.
• Before a medical procedure: shown in one trial. In a randomized trial of 75 older adults before an endoscopy, 25 in each group, fear and anxiety scores were lower after four-seven-eight breathing or squeezing a stress ball than in the control group, and the anxiety drop was larger with the breathing [S8].
• Sleep: one study in people with tinnitus. In a randomized trial of 48 people with tinnitus (23 practising for 6 weeks, 25 controls), four-seven-eight practice lowered tinnitus handicap, stress, anxiety and insomnia-severity scores compared with an information session alone [S9]. Sleep was a secondary outcome, and the population was people with tinnitus, not healthy sleepers.

What about one-minute practices?

Short practices have partial support. In a pilot study in daily life, 47 university students used one minute of box breathing or cyclic sighing at moments of acute threat; both reduced state anxiety more than a passive control [S10]. There was an unexpected cost: reaction times on an attention test were longer after either exercise than after the control [S10]. In a pilot trial in an orthopaedic clinic, a single four-minute recorded session of cyclic sighing in the waiting room reduced pain unpleasantness and intensity compared with an attention-matched control; anxiety and depression symptoms did not differ [S11]. Both are small pilots, and neither measured HRV.

What has never been tested?

• Four-seven-eight and falling asleep in healthy people: no data. No indexed study has tested whether it helps healthy people fall asleep. The popular promise that it puts you to sleep in a minute is a media claim with no study behind it.
• Box breathing against four-seven-eight: never compared directly. No study has put the two head to head on any outcome.
• Repeated practice of named techniques and HRV. The HRV results above come from single sessions or from trials that did not report HRV between styles.

What is the overall picture?

Slow breathing has the broadest support. A meta-analysis of 223 studies found higher vagally mediated HRV during slow breathing, right after a session and after multi-session programmes [S12]. Patterns with a long, slow exhale have the most consistent results in the comparisons above [S1] [S5], although a longer exhale has not clearly beaten an equal one [S6]. Branded techniques have rarely been tested against each other, and no named technique has been shown to beat ordinary slow breathing. The full evidence on slow breathing is on slow breathing; breathing with real-time heart-rhythm feedback is covered on HRV biofeedback.

By evidence class.

• Established. Slow breathing is associated with higher vagally mediated HRV during and after practice [S12].
• Context-dependent. Four-seven-eight lowered anxiety before an endoscopy in older adults [S8] and questionnaire scores, including insomnia severity, in people with tinnitus [S9].
• Emerging. Cyclic sighing beat meditation for mood in one trial [S1]; slow breathing beat box breathing after interval training in one study [S3]; box breathing and a long exhale were equivalent before stress [S5]; one-minute practices eased anxiety in a pilot [S10]; single sighs act as a brief activator [S2].
• Unknown. Four-seven-eight and falling asleep in healthy people; box breathing against four-seven-eight; long-term HRV effects of any named technique.

What it does not tell you

• One study is not a ranking. Each comparison above comes from a single study in a specific group, such as students, cadets, older patients or people with tinnitus.
• Calmer is not the same as higher HRV. Several techniques reduced anxiety without changing HRV [S5] [S7].
• No technique here treats a condition. The clinical studies tested short-term relief before a procedure, in a waiting room or alongside tinnitus care.
• Breath holds are not for everyone. Box breathing and four-seven-eight include holds; stop if you feel dizzy or short of breath. Chest pain, fainting or severe breathlessness need medical care, not a breathing exercise.

In ONDA

ONDA's practices use slow, guided breathing with spoken and visual guidance rather than a fixed numeric pacer; the app has no box-breathing or four-seven-eight timer. ONDA shows your pulse live during a practice, from the iPhone camera or an Apple Watch, the camera also gives a breathing-rate estimate, and an Apple Watch adds a live coherence score — ONDA's own measure of how smooth the heart-rhythm oscillation is, not a clinical HRV measurement. ONDA has no study of its own effectiveness, and the comparisons on this page do not show that any ONDA practice beats another technique. ONDA does not diagnose or treat any condition. See what ONDA measures.