Effects of a brief resonance frequency breathing intervention on heart rate variability and perceived stress in postgraduate students: a pilot and feasibility study

Introduction Stress during postgraduate education can undermine well-being, academic performance, and physiological regulation. Resonance frequency breathing (RFB) is a slow-paced breathing technique associated with enhanced autonomic regulation, as indexed by heart rate variability (HRV). However, validated protocols are often time-intensive, limiting real-world implementation. This pilot study evaluated the preliminary effects, feasibility, and acceptability of a brief, app-guided RFB intervention during an academically demanding period. Methods Twelve postgraduate students were randomly assigned to an RFB intervention group ( n = 6) or a no-intervention control group ( n = 6). Intervention participants completed daily 10-minute sessions for three weeks at their individually determined resonance frequency. The standard deviation of normal-to-normal intervals (SDNN), root mean square of successive differences (RMSSD), and perceived stress, measured using a PSS-10 adapted to a one-week recall period, were assessed weekly. Post-intervention qualitative interviews with five intervention participants explored feasibility, perceived impact, engagement, and future application. Results Between-group comparisons of change scores showed significant differences for SDNN at Weeks 2 ( p = 0.004, r = 0.94) and 3 ( p = 0.026, r = 0.78), and for RMSSD at Week 3 ( p = 0.026, r = 0.78) with values increasing in the RFB group and declining in controls. No significant between-group difference in perceived stress was observed. By Week 3, however, the intervention group showed a mean decrease of 6.00 points from baseline, compared with a 4.50-point increase among controls ( r = −0.47, p = 0.199). Interviewed participants generally experienced the protocol as manageable, reported perceived benefits for stress coping, and expressed interest in continuing RFB. Discussion In this pilot sample, the brief RFB protocol was feasible and acceptable and was associated with increases in resting HRV relative to controls during heightened academic demand. The study did not demonstrate a significant between-group difference in perceived stress. Given the small sample, short duration, and absence of an active control, the findings are preliminary. Larger controlled trials with follow-up assessments are needed to evaluate efficacy, durability, and real-world implementation.