Acute Stress Recovery: The Impact of Meditation on Heart Rate Variability Patterns

Heart rate variability (HRV) is a non-invasive tool for measuring autonomic nervous system function and may indicate the response to an acute stressor. HRV measures the frequency and time domains of an ECG and can reflect input of the sympathetic (SNS) and parasympathetic (PNS) nervous systems. Purpose: To examine the effects of a brief guided meditation following an acute stressor on HRV measures. Methods: 14 participants (ages 18-21) volunteered, gave informed consent, and completed the study. Using a within-subject and counterbalance design, participants were distressed using a Cold Pressor Test (CPT), followed by a 5-minute recovery of either quiet sitting (SIT) or a mindfulness-based intervention (MBI). Participants sat for 10 minutes to establish a baseline, completed a 3-minute 2-foot immersion Cold Pressor Test (CPT), and a post-stress recovery of either SIT or MBI. A Polar H10 heart rate monitor collected the heart rate (HR) data, and HRV was analyzed using short-term measures with Kubios software. The analysis was conducted during the last minute of baseline, during CPT, and the last minute of both SIT and MBI. In addition to HR, root mean square successive differences (RMSSD), the standard deviation of normal-normal intervals (SDNN), high-frequency power (HF), low-frequency power (LF), and LF/HF ratio were determined. Data were analyzed with SPSS V.28 using a 2 (condition) x 3 (time) ANOVA with repeated measures for each variable. Results: There was no significant difference in HR, RMSSD, SDNN, HF, or LF during the last minute of resting or during the CPT in either condition. However, MBI achieved a significantly lower HR than SIT (70.1 ± 11.1 bpm vs. 74.0 ± 8.7 bpm, respectively, p=0.03). In the time domain, MBI produced a significant increase compared to SIT for SDNN (79.2 ± 35.4 ms vs. 46.8 ± 23.5 ms, respectively, p<0.01) and a non-significant increase in RMSSD (57.9 ± 38.4 ms vs. 39.8 ± 27.9 ms, respectively, p=0.13). In the frequency domain, MBI showed significantly lower HF (21.1 ± 17.2 n.u. vs. 38.3 ± 24.1 n.u., respectively, p=0.03), a significant increase in LF (79.0 ± 17.3 n.u. vs. 57.8 ± 25.0 n.u., respectively, p<0.01) and an increased LF/HF ratio during MBI (6.5 ± 4.5 vs. 3.2 ± 3.7, p=0.04) compared to SIT. Conclusion: Following a CPT, MBI may attenuate HR and engage the PNS, as shown by a significant increase in SDNN and amplified RMSSD. Increased HF is generally a measure of PNS activity; however, the reduced HF and corresponding rise in LF may be explained by the MBI utilizing slower breathing than SIT, which may have shifted the HF into the LF range, as seen by the increased LF/HF ratio. Messiah University, Mechanicsburg, PA This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.