Effects of exercise training on autonomic cardiovascular control in individuals with spinal cord injury: a systematic...

Autonomic cardiovascular control is often disrupted following a spinal cord injury (SCI), resulting in impaired autonomic cardiac regulation and hemodynamic instability. A systematic preregistered review following existing guidelines was undertaken to evaluate the effect of exercise training on noninvasive measures of autonomic cardiovascular control, including orthostatic intolerance, blood pressure variability (BPV), baroreflex function, and heart rate variability (HRV) in adults with SCI. Seven databases were searched from inception to October 2025. Experimental studies (randomized controlled trials, nonrandomized controlled trials, or pre-post studies) consisting of exercise interventions of ≥2 wk evaluating measures of orthostatic tolerance, BPV, baroreflex function, and/or HRV in adults (≥18 yr old) with SCI were included. Risk of bias and study quality were assessed. Of 1,208 unique records identified, 16 studies (329 participants) were included: 8 randomized controlled trials, 3 nonrandomized controlled trials, and 5 pre-post studies. Five of seven studies reported no change in orthostatic intolerance following exercise training, whereas three of five studies found no changes in power spectral analysis of BPV. Conversely, all five studies reporting baroreflex outcomes found improved function, with enhanced cardiovagal baroreflex sensitivity or effectiveness index after training. The 13 studies assessing autonomic cardiac control through HRV reported mixed results, irrespective of whether time- or frequency-domain analyses were used. This review provides preliminary evidence that exercise training can improve baroreflex function in adults with SCI. However, current evidence remains inconclusive regarding whether exercise training can improve HRV, BPV, and the ability to tolerate postural stress and thus prevent orthostatic hypotension.