How Stable Is Breathing at Resonance Frequency? A Test–Retest Study on Individual Variability and Its Associations With Emotion Regulation and Lifestyle

An individual's resonance frequency (RF) is considered the optimal breathing rate for eliciting cardiovascular and autonomic benefits and is often used to guide home breathing practice. However, evidence on the stability of RF over time is scarce. Previous research reported poor 1 week test-retest reliability in a small sample. The present study aimed to replicate and extend these findings in a larger community sample while adhering to an RF determination pro. Fifty-one participants completed a 1-week test-retest assessment of RF. Group-level RF remained stable, but individual-level stability was low (ICC = 0.10), with approximately 25% of participants showing differences larger than 0.5 breaths per minute. Trend-level associations indicated that higher physical activity and more use of acceptance and self-support emotion regulation skills were linked to smaller RF test-retest variability. This study demonstrates that resonance frequency breathing is not equally stable across individuals, with a substantial subset showing meaningful shifts over just 1 week. By identifying lifestyle and emotion regulation factors linked to greater stability, our findings challenge the assumption that a single RF assessment is sufficient. This work advances the field by highlighting when individualized RF may (and may not) offer added value in practice. These findings suggest that RF is not uniformly stable across individuals, raising questions about the necessity and clinical relevance of repeated or individualized RF assessment. Future research should examine for whom RF remains stable and whether tailoring breathing rates provides measurable physiological or clinical benefits.