Effect of high-intensity interval exercise on pain, disability, and autonomic balance in patients with nonspecific chronic low back pain

Abstract

Aim: To evaluate the effect of six weeks of high-intensity interval exercise (HIIE) program on pain, disability, and autonomic balance in patients with nonspecific chronic low back pain (NSCLBP). Materials and methods: Eighty patients with mild to moderate NSCLBP of either sex, with ages of 18-65 years, were recruited from the physiotherapy department at King Fahd University Hospital, AlKhobar. They were randomly assigned to the control group (n=40), which received standard regular physiotherapy, or the experimental group (n= 40), which received HIIE in addition to the standard regular physiotherapy. Pre- and post-intervention (after 6 weeks) assessments included pain intensity through Numerical Rating Scale (NRS), disability through Oswestry Disability Index (ODI), and autonomic balance through heart rate variability (HRV) parameters and baroreceptor sensitivity (BRS) at rest and in response to an orthostatic challenge. Results: There was a significant improvement in pain as well as disability in both groups, with a greater improvement in both variables in favor of the HIIE group. For the HRV parameters after 6 weeks of intervention, the control group had a statistically significant reduction in high frequency (HF), and in response to the orthostatic challenge, a significantly higher rise in the normalized low frequency (LFnu) compared to the baseline. BRS showed a significant reduction and heart rate recovery was significantly faster post-intervention in the HIIE group in the 2nd and 3rd minutes, compared to the baseline values. Conclusions: HIIE can be a useful addition to the exercise regimens in practice for NSCLBP patients, as adding HIIE to the standard physiotherapy caused greater improvement in pain and disability compared to standard physiotherapy alone, with better autonomic regulation after six weeks of treatment.