Heart adaptations to long-term aerobic training in paraplegic subjects : an echocardiographic study

Study Design. Case-control. Objectives. To execute an echocardiographic comparison between trained and untrained spinal cord injury (SCI) subjects and to evaluate whether long-term heart adjustments to endurance training are comparable with those observed in able-bodied (ABL) subjects. Setting. Italy. Methods. We enrolled: 1) 17 male SCI patients (lesion level T1-L3, 34±8 years, BMI 23.0±2.8 kg/m2), 10 of whom were aerobically trained for >5 years (SCIT); 2) 18 age, sex and BMI-matched ABL subjects (35±6 years, BMI 23.6±2.8 kg/m2), 10 of whom were aerobically trained for >5 years (ABLT). Training frequency and volume were recorded by a dedicated questionnaire. All subjects underwent a trans-thoracic echocardiography; SCI subjects also performed an exhaustive incremental exercise test. Comparisons were made between ABL and SCI groups and, within each group, between trained and untrained subjects (ANOVA). Results. Effects of SCI. Compared to ABL subjects, SCI patients showed lower end-diastolic volume (76±21 vs 113±23 ml, P<0.05) and ejection fraction (61±7 vs 65±5%, P <0.05). Effects of Training. Compared to untrained status, the intra-ventricular septum thickness (SCI, +18%; ABL +4%), the posterior wall thickness (SCI, +17%; ABL +2%) and the total normalized heart mass (SCI, +48%; ABL +5%) were higher in both SCIT and in ABLT. VO2peak was higher in SCIT subgroup compared to SCIU. Conclusions. Heart seems to positively adapt to long-term endurance training in SCI patients. Regular exercise may therefore positively affect heart morphology and function in these subjects. This may limit the cardiovascular risk in SCI individuals.