Box breathing and prolonged exhalation reduces markers of physiological stress reactivity in response to a virtual trier social stress test.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 42388906 · doi:10.1016/j.cpnec.2026.100360
What was done
Sixty-six participants were randomly assigned to normal breathing (n = 22), prolonged exhalation (n = 22), or box breathing (n = 22) prior to completing a modified virtual Trier Social Stress Test. Investigators measured subjective and physiological markers before and after the stressor, including state anxiety, heart rate, heart rate variability (RMSSD, SDNN), salivary alpha-amylase, secretory immunoglobulin A, cortisol, and cognitive performance via Stroop color-word and mental arithmetic tasks. Data were analyzed using a linear mixed model with a random subject intercept.
What was found
The abstract reports no exact numerical values, effect sizes, or p-values. The stress test elicited significant increases in heart rate, state anxiety, salivary alpha-amylase, and secretory immunoglobulin A. Both prolonged exhalation and box breathing significantly attenuated post-stressor increases in heart rate, state anxiety, and salivary alpha-amylase compared to normal breathing. Heart rate variability, cortisol, and cognitive performance were statistically unchanged across the three conditions.
Why it matters
Brief breathwork techniques, specifically box breathing and prolonged exhalation, can dampen subjective anxiety and peripheral sympathetic reactivity following an acute psychosocial stressor.
Limits
The abstract reports no numerical point estimates, effect sizes, or confidence intervals. The sample size is small with 22 participants per arm, testing was conducted in a laboratory virtual simulation rather than an occupational setting, and the interventions showed no measurable effect on cortisol, heart rate variability, or cognitive performance.
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