Abstract

Objective: Ageing of the human heart is characterized by morphological, functional and metabolic changes. Short-term interventions and cross sectional studies in older individuals questioned the possibility that physical exercise may revert these alterations. In this study we aimed to assess whether in middle-aged men involved in regular and long lasting physical activity these alterations were attenuated.

Design: Left ventricular (LV) MRI and 3D-ISIS 31P-MRS were performed using a 1.5T scanner in 20 healthy, young and 25 healthy middle-aged non-obese men with a sedentary life-style (11 young and 14 middle-age) or undergoing regular aerobic oxidative training (9 young and 11 middle-age). Insulin sensitivity was estimated by the HOMA-2 model.

Results: Sedentary young and middle-aged men were not different with respect to LV morphological parameters and systolic function. The PCr/ATP ratio (marker of high energy phosphates metabolism) and the LV E/A peak flow ratio were lower in sedentary middle-aged than physically active subjects. Parameters of LV systolic function and the PCr/ATP ratio were not different in the middle-aged than in the young trained men; the E/A peak flow ratio was higher in the middle-aged trained men than in the middle-aged sedentary men. Within the entire population, the PCr/ATP ratio and the E/A peak flow ratio were associated with insulin sensitivity.

Conclusions: Trained middle-aged subjects showed a better pattern of LV energy metabolism and of diastolic function than the sedentary counterparts. At this age the exercise-related cardiac benefits were detectable when physical exercise was performed regularly and for a long period of time.