The Practical Utility of Functional Electrical Stimulation Exercise for Cardiovascular Health in Individuals with Spinal Cord Injury

Cardiovascular disease (CVD) is a primary cause of morbidity and mortality in individuals with chronic spinal cord injuries (SCI). This review focuses on the importance of exercise, specifically functional electrical stimulation (FES) exercise, as an intervention to reduce CVD risk in individuals with SCI. Regular exercise of sufficient intensity (~6 METS) decreases overall risk of CVD in able-bodied individuals. Individuals with SCI have difficulty achieving this intensity since paralyzed muscle cannot contribute to the exercise response. FES is a practical intervention in which paralyzed musculature is stimulated to create joint movements that mimic exercise. FES increases oxygen consumption, cardiac output, and cardiovascular stress but to a much lesser extent than exercise performed by non-paralyzed muscle, possibly due to numerous disrupted feedforward and feedback neural pathways that limit cardiovascular and pulmonary adjustments. FES can be combined with exercise of non-paralyzed muscle (hybrid-FES) to overcome some of these limitations and further increase exercise intensity and cardiovascular responses. However, the addition of supplemental therapies may still be needed for individuals with SCI to obtain health benefits of exercise and reductions in CVD risk similar to uninjured individuals. Hybrid-FES is a practical intervention to increase exercise intensity and oxygen consumption to levels identified to reduce CVD risk, but FES alone should not be considered synonymous with voluntary exercise. However, potential adjunctive therapies may still be needed for individuals with SCI to obtain health benefits of exercise and reductions in CVD risk similar to uninjured individuals.