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

ABSTRACT

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 to those observed in able-bodied (ABL) subjects. SETTING: Italy. METHODS: We enrolled (1) 17 male SCI patients (lesion level T1-L3, 34±8 years, body mass index (BMI) 23.0±2.8 kg m(-2)), 10 of whom were aerobically trained for >5 years (SCI(T)); (2) 18 age-, sex- and BMI-matched ABL subjects (35±6 years, BMI 23.6±2.8 kg m(-2)), 10 of whom were aerobically trained for >5 years (ABL(T)). 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, between trained and untrained subjects within each group (analysis of variance). RESULTS: Effects of SCI-Compared with 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 with 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 SCI(T) and in ABL(T). VO2peak was higher in the SCI(T) subgroup compared with the SCI(U) group. CONCLUSIONS: Heart seems to positively adapt to long-term endurance training in SCI patients. Regular exercise may therefore increase heart size, septum and posterior wall thickness, which likely contributes to improved VO2peak. These morphological and functional changes may reduce cardiovascular risk in SCI individuals.