Aim. to assess the impact of a 6-weeks high-intensity interval exercise (HIIE) regimen on pain, disability, as well as autonomic balance in women with nonspecific chronic low back pain (NSCLBP). Materials and methods. Eighty females with mild to moderate NSCLBP, with ages of 18-65 years, were recruited from the physiotherapy department at King Fahd University Hospital, AlKhobar. They were assigned randomly into the control group (n = 40), which received standard regular physiotherapy, or the experimental group (n = 40), which received HIIE as well as conventional regular physiotherapy. Pre- and post-intervention (after 6 weeks) assessments included pain intensity via Numerical Rating Scale (NRS), disability via Oswestry Disability Index (ODI), as well as autonomic balance via heart rate variability (HRV) parameters & baroreceptor sensitivity (BRS) Both at rest and in reaction to an orthostatic challenge. Results. Both groups experienced significant improvements in pain and disability, with the HIIE group experiencing a higher improvement in both variables. 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 valuable addition to NSCLBP patients’ exercise routines in practice, since adding HIIE to standard physiotherapy resulted in more reduction in pain, disability compared to conventional physiotherapy alone, with enhanced autonomic regulation after six weeks of treatment.

Keywords:
chronic low back pain, Oswestry disability index, autonomic balance, heart rate variability