Heart rate variability responses to instrument-assisted atlas (C1) chiropractic manipulation: A randomized placebo-controlled trial.

INTRODUCTION

Musculoskeletal pain is often linked to dysfunctions of the ANS. Instrument-assisted chiropractic manipulation is promising for modulating HRV through the ANS.

OBJECTIVE

To assess the impact of chiropractic manipulation on HRV in individuals with musculoskeletal pain compared to a placebo.

METHODS

A randomized clinical trial included 64 participants aged 18-60 years (mean age = 32 ± 10.4) with acute or chronic musculoskeletal pain. The intervention group (IG) received a single high-velocity, low-amplitude impulse on the bilateral transverse processes of C1, while the control group (CG) received a placebo. HRV was recorded both pre- and post-intervention using a Polar H10 monitor and analyzed with Kubios HRV Standard (v3.5.0). Analysis was through repeated-measures ANOVA (p < 0.05).

RESULTS

The IG showed a significant LF/HF change (p = 0.013), and the CG had a significant SD1/SD2 change (p = 0.02) in intra-group comparisons. No significant differences were found between IG and CG for variables such as SDNN, NN50, PNN50 %, SD1, SD2, LF/HF, and SD1/SD2.

DISCUSSION: Both interventions induced HRV changes without significant intergroup differences, suggesting uncontrolled factors may influence the autonomic response.

CONCLUSION

Instrument-assisted chiropractic manipulation of C1 did not significantly change HRV vs. placebo, indicating the need for further studies on external variables.