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 T 1 -L 3 , 34±8 years, body mass index (BMI) 23.0±2.8 kg m À2 ), 10 of whom were aerobically trained for 45 years (SCI T ); (2) 18 age-, sex-and BMI-matched ABL subjects (35 ± 6 years, BMI 23.6 ± 2.8 kg m À2 ), 10 of whom were aerobically trained for 45 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, Po0.05) and ejection fraction (61±7% vs 65±5%, Po0.05). 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 . VO 2 peak 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 VO 2 peak. These morphological and functional changes may reduce cardiovascular risk in SCI individuals. INTRODUCTIONThe positive effects of endurance training on heart morphology and function are well acknowledged in able-bodied (ABL) individuals: besides the typical development of bradycardia and the improvement in coronary perfusion, cardiac morphology usually shifts toward a physiological left ventricular (LV) hypertrophy with increased mass and internal volume of the left ventricle, and improved systolic and diastolic functions (for a review, see Pavlik et al. 1 ). In ABL endurance-trained individuals, the increased stroke volume finally yields an augmented cardiac output during exercise compared with untrained subjects. 2 A previous study demonstrated a reduction in LV mass and dimension in tetraplegic subjects, 3 and a more recent study showed an altered LV diastolic function and a subclinical decrease in systolic function in spinal cord injury (SCI) individuals. 4 In these patients, the reduced venous return due to the loss of sublesional vascular sympathetic innervation and of the muscular pump may cause a reduced adaptation of stroke volume to exercise, 5 which needs to be compensated by a higher submaximal heart rate, compared with that observed in ABL subjects. 6,7 Indeed, Dela et al. 5 demonstrated a stroke volume increase of about ...

The effect of blood volume and volume loading on left ventricular diastolic function in individuals with spinal cord injury

“…Furthermore, the observed reduction in LVIDd demonstrated by the spinal cord injured participants is in agreement with several previous reports. [10][11][12]28 However, the commonly reported reduction in LVM in this population [8][9][10]28,29 was not observed in the current participants. As mentioned, the smaller LVIDd can be explained by the chronic reduction in preload, as demonstrated by a lower end-diastolic volume and blood volume.…”

“…[11][12][13][14] It has been proposed that the chronic physical inactivity after SCI may have a role in such diastolic impairments, as active spinal cord injured individuals have been shown to present better diastolic patterns compared with sedentary ones. 11,14 However, Maggioni et al 29 reported no difference in diastolic function between trained and untrained spinal cord injured individuals and De Groot et al 8 reported no difference in diastole between able-bodied individuals and sedentary individuals with severe tetraplegia. In addition, Driussi et al 12 reported lower diastolic function in those with SCI compared with able-bodied individuals even after controlling for levels of physical activity, suggesting that physical activity did not have a major role in the diastolic impairments.…”

Differences in Left Ventricular Global Function and Mechanics in Paralympic Athletes with Cervical and Thoracic Spinal Cord Injuries

“…Additionally, indices of LV mechanics are sensitive to increases and decreases in sympathetic activity (Weidemann et al, 2002 ; Akagawa et al, 2007 ), which may provide insight into the influence of lesion level on LV performance. Few studies have performed echocardiographic assessments in athletes with SCI (Huonker et al, 1998 ; Gates et al, 2002 ; Schumacher et al, 2009 ; Maggioni et al, 2012 ; West et al, 2012a ; De Rossi et al, 2014 ), with none of these investigations examining LV mechanics. Given evidence that global LV systolic dysfunction is associated with impairments in LV mechanics, and that these functional changes may limit exercise performance, the examination of LV structure, function and mechanics in athletes with SCI may help to elucidate potential factors limiting cardiac responses to exercise.…”

Can combined aerobic and muscle strength training improve aerobic fitness, muscle strength, function and quality of life in people with spinal cord injury? A systematic review

“…6 Muscle strength is decreased because neurological input to the affected muscles that retain partial innervation is deficient, leading to the loss of normal activation timing and force-generating capacity. 7 Secondary to the loss of neural inputs are negative musculoskeletal adaptations such as transformation to faster muscle fibers (IIa, IIb) 7 increased contractile speed and increased fatigue in partially paralyzed and also innervated muscles in people with SCI.…”