Dysfunctional autonomic regulation and slower cardiovascular recovery in patients with chronic low back pain after physical maximal effort: cross-sectional study

Abstract Objective To compare heart rate recovery (HRR), rate-pressure product (RPP), and heart rate variability (HRV) between individuals with chronic low back pain (CLBP) and healthy controls following a maximal exercise test, in order to assess autonomic and cardiovascular recovery patterns. Methods A cross-sectional study was conducted with 51 participants divided into two groups: CLBP (n = 23) and controls (n = 28). Participants underwent a maximal treadmill test with continuous heart rate and blood pressure monitoring. HRR was evaluated at 10 s, 1, 2, and 3 min post-exercise. RPP was calculated at rest, peak effort, and recovery. HRV was analyzed in both time and frequency domains before and after the test. Statistical analyses included Student’s t -test, two-way ANOVA, and Shapiro–Wilk normality tests ( p < 0.05). Results The CLBP group showed significantly lower HRR values across all recovery intervals ( p < 0.001) and higher RPP at rest, peak effort, and recovery ( p < 0.001), indicating increased myocardial workload. HRV indices were consistently lower in the CLBP group compared with controls, both pre- and post-exercise (SDNN: 36.6 ± 3.52 vs. 41.0 ± 3.85 ms; RMSSD: 29.5 ± 4.48 vs. 39.8 ± 4.54 ms; p < 0.001). Frequency domain analysis revealed reduced LF and HF components and higher LF/HF ratio in the CLBP group. Conclusion CLBP exhibit impaired autonomic regulation, which is characterized by a slower heart rate recovery, reduced heart rate variability, and an increased myocardial workload after maximal exercise. These findings suggest parasympathetic dysregulation and reinforce the need for multidisciplinary interventions that target cardiovascular and autonomic restoration in this population. Highlights Individuals with chronic low back pain show impaired autonomic modulation and slower cardiovascular recovery after maximal exercise. Heart rate recovery and HRV may serve as noninvasive markers of autonomic dysfunction in chronic pain populations.