De Couck · International journal of psychophysiology : official journal of the International Organization of Psychophysiology 2019 · randomized controlled trial · n=86

How breathing can help you make better decisions: Two studies on the effects of breathing patterns on heart rate variability and decision-making in business cases.

Level 2 - randomized trial

Individual randomized controlled trials

PubMed 30826382 · doi:10.1016/j.ijpsycho.2019.02.011 · record verified 2026-08-26

What was done

In Study 1, 30 healthy adults performed symmetric breathing (equal inhale/exhale timing), skewed breathing (longer exhalation than inhalation), or watched a neutral control film to evaluate effects on time- and frequency-domain heart rate variability (HRV). In Study 2, 56 students were randomized to 2 minutes of skewed breathing or a 2-minute waiting control immediately prior to completing a 30-minute multiple-choice business decision-making task. Self-reported stress was measured before and after the task.

What was found

In Study 1, both slow breathing patterns significantly increased time- and frequency-domain HRV parameters from baseline, whereas viewing the film did not. In Study 2, controls reported significant elevations in stress levels after the task, whereas the breathing group did not. Participants in the breathing group also achieved a significantly higher percentage of correct answers on the decision-making task compared to controls. Specific numerical values and effect sizes were not reported in the abstract.

Why it matters

This suggests that brief, accessible vagal breathing interventions can rapidly modulate autonomic state, blunt acute stress reactivity, and enhance cognitive accuracy during high-demand analytical tasks.

Limits

Sample sizes were modest (n = 30 and n = 56) and restricted to healthy volunteers and student populations. The decision-making assessment was a simulated laboratory test rather than a real-world setting, and the abstract omits exact numerical values, effect sizes, and whether HRV improvements persisted throughout the cognitive challenge.