Cardiovascular disease, when considered after the first year post-injury within the US Model Systems database, has been acknowledged as the leading cause of death in persons with SCI, supplanting respiratory complications and previous to that septicaemia (Whiteneck et al. 1992; DeVivo et al. 1999). Cardiovascular disease is currently also the leading cause of death in the able-bodied population. A recent review by Myers et al. (2007) noted that there is a significantly high prevalence of cardiovascular disease in persons with SCI with rates of symptomatic cardiovascular disease in SCI of 30–50% in comparison to 5–10% in the general able-bodied population. Physical activity interventions comprise a significant part of the strategy in dealing with cardiovascular disease and the reader is referred to SCIRE Chapter: Cardiovascular Health and Exercise Following Spinal Cord Injury (Warburton et al. 2010) for more information on this topic. In the following section, we present those specific evidence-based statements and bottom-line conclusions from this chapter related to physical activity.
Conclusions – From SCIRE: Cardiovascular Health and Exercise Following SCI
Exercise Rehabilitation and Cardiovascular Fitness
There is level 1b evidence (Millar et al. 2009) that BWSTT improves cardiac autonomic balance in persons with tetraplegia and paraplegia (with similar results for varying degrees of lesion level and severity).
There is level 4 evidence that BWSTT increases peak oxygen uptake and heart rate, and decreases the dynamic oxygen cost for persons with SCI.
There is level 4 evidence (Ditor et al. 2005a) that body-weight support treadmill training (BWSTT) improves cardiac autonomic balance in persons with incomplete tetraplegia.
There is level 4 evidence (de Carvalho and Cliquet 2005) that BWSTT can lead to improvements in cardiac autonomic balance in a subset of individuals with motor-complete SCI who respond to ambulation with moderate-to-large increases in heart rate.
Level 4 evidence (Ditor et al. 2005b) indicates that BWSTT can improve arterial compliance in individuals with motor-complete SCI.
There is level 2 evidence (de Carvalho et al. 2006) that neuromuscular electrical stimulation gait training can increase metabolic and cardiorespiratory responses in persons with complete tetraplegia.
There is limited evidence that BWSTT can improve indicators of cardiovascular health in individuals with complete and incomplete SCI.
Upper Extremity Training
There is level 1 evidence (De Groot et al. 2003) that vigorous intensity (70–80% heart rate reserve) exercise leads to greater improvements in aerobic capacity than moderate intensity (50-60% heart rate reserve) exercise.
The relative importance of changes in cardiac function and the ability to extract oxygen at the periphery in persons with SCI after aerobic training remains to be determined.
There is level 2 evidence that hand cycling exercise increases the power output, oxygen consumption, and muscle strength in paraplegic, but not tetraplegic subjects during active rehabilitation. Conversely, there is level 4 evidence that hand cycling increases power output and oxygen consumption in subjects with tetraplegia.
There is level 1 evidence (Davis et al. 1987) that moderate intensity aerobic arm training (performed 20–60 min/day, three days/week for at least 6-8 weeks) is effective in improving the aerobic capacity and exercise tolerance of persons with SCI.
Persons with tetraplegia and paraplegia can improve their cardiovascular fitness and physical work capacity through moderate intensities of aerobic exercise or resistance training, although optimal program parameters are not known.
Functional electrical stimulation (FES)– Lower Limb Cycle Ergometry and Hybrid (Upper and Lower Limb) and Other Electrically-Assisted Training Programs
There is level 4 evidence from pre-post studies that FES training performed for a minimum of three days per week for two months can be effective for improving musculoskeletal fitness, the oxidative potential of muscle, exercise tolerance, and cardiovascular fitness.
There is level 3 evidence (Jae et al 2008) that upper body exercise training can improve arterial structure and function in those with SCI.
There is level 4 evidence that FES training is effective in improving exercise cardiac function in persons with SCI.
There is level 5 evidence that arm-cranking exercise assisted by FES increases peak power output, and may increase oxygen uptake.
Based on the changes observed in VO2max and findings from able-bodied individuals a consensus (level 5; Expert Opinion) was derived stating that aerobic training is effective in improving the ability to extract oxygen at the periphery in persons with SCI.
Interventions that involve FES training a minimum of 3 days per week for 2 months can improve muscular endurance, oxidative metabolism, exercise tolerance, and cardiovascular fitness.
There is level 1 (De Groot et al. 2003) and level 4 (Chilibeck et al. 1999; Mohr et al. 2001; Jeon et al. 2002) evidence that both aerobic and FES training (approximately 20–30 min/day, three days/week for eight weeks or more) are effective in improving glucose homeostasis in persons with SCI.
There is level 4 evidence that the changes in glucose homeostasis after aerobic or FES training are clinically significant for the prevention and/or treatment of type 2 diabetes.
Aerobic and FES exercise training may lead to clinically significant improvements in glucose homeostasis in persons with SCI. Preliminary evidence indicates that a minimum of 30 min of moderate intensity training on 3 days per week is required to achieve and/or maintain the benefits from exercise training.
Lipid Lipoprotein Profiles
There is level 1 evidence (De Groot et al. 2003) to suggest that aerobic exercise training programs (performed at a moderate to vigorous intensity 20-30 min/day, 3 days per week for 8 weeks) are effective in improving the lipid lipoprotein profiles of persons with SCI.
Preliminary evidence (level 4; Solomonow et al. 1997) also indicates that FES training (3 hours/week, for 14 weeks) may improve lipid lipoprotein profiles in SCI.
Aerobic and FES exercise training may lead to improvements in lipid lipoprotein profiles that are clinically relevant for the at-risk SCI population. The optimal training program for changes in lipid lipoprotein profiles remains to be determined. However, a minimal aerobic exercise intensity of 70% of heart rate reserve on most days of the week appears to be a good general recommendation for improving lipid lipoprotein profiles in persons with SCI.