Cardiorespiratory fitness and training in quadriplegics and paraplegics

With the growing interest in exercise and sport and the significance of cardiovascular disease in the spinal cord injured population, the role of endurance training in improving cardiovascular health is of particular interest. Ordinary daily activities of those with spinal cord injury are usually not adequate to maintain cardiovascular fitness, and lack of participation in a regular activity programme may result in a debilitative cycle. As this occurs, there is a reduction in functional work capacity which may limit independence, and the reduction in cardiovascular fitness may increase the risk for cardiovascular disease. Work capacity in those with spinal cord injury is limited by loss of functional muscle mass and sympathetic control. Sympathetic nervous system impairment limits control of regional blood flow and cardiac output, and maximum heart rate following cervical lesions may be reduced to 110 to 130 beats/min. However, endurance training in quadriplegics and paraplegics can elicit improvements in exercise performance similar to those observed in able-bodied individuals. Review of 13 cardiorespiratory training studies involving spinal cord injured subjects revealed average improvements of 20% in VO2max and 40% in physical work capacity after 4 to 20 weeks of training. Based upon the positive results of these studies, the general endurance training guidelines for the normal population appear to also be appropriate for the spinal cord injured population. These guidelines can be followed during participation in a number of different activities and sports including wheelchair pushing, arm crank ergometry, aerobic swimming, ambulation training, canoeing and wheelchair basketball. There is no evidence that intense training and competition is harmful, but special areas of risk as a result of impairments in sensation, cardiovascular function, autonomic function and temperature regulation must be considered. The long term benefits of endurance training in those with spinal cord injury has not been adequately studied, but there is suggestion that similar physiological and psychological changes may occur as in able-bodied individuals.