Exercise beneficial for sedentary seniors but does not improve LV compliance
MedWire News: Study results suggest that previously sedentary adults aged over 65 years cannot reverse the cardiac stiffening of years of inactivity by adopting a progressively vigorous 1-year exercise program.
Such a program however, may improve aerobic exercise capacity and arterial function, therefore offering some benefit to cardiovascular (CV) health.
A team of researchers, led by Benjamin Levine (Texas Health Presbyterian Hospital, Dallas, USA), assessed the baseline cardiac function of 24 adults aged over 65 years. Of these, 12 had a predominantly sedentary lifestyle, and 12 were Masters athletes with a long history of regular exercise training.
Measures of cardiac function assessed in each participant included Starling and left ventricular (LV) pressure-volume curves, magnetic resonance imaging assessment of cardiac morphology, arterial stiffness, and maximal exercise testing.
After 1 year of endurance training, which featured a gradual increase in exercise duration and intensity, the cardiac function of the previously sedentary participants was reassessed.
Of note, only nine of the 12 sedentary seniors completed the year long exercise program.
Levine and colleagues found that prior to the training program, sedentary participants had significantly smaller LV mass, LV end diastolic volume (LVEDV), stroke volume indexes, LV compliance, and maximal oxygen consumption (VO2max) than the Masters athletes.
After 1 year of training, little change was observed in the cardiac compliance of the previously sedentary participants; however, VO2max increased by 19% from 22.8 ml/kg/ml at baseline to 27.2 ml/kg/ml at 1 year (p<0.001).
LV mass also increased by 10%, from 64.5 g/m2 at baseline to 71.2 g/m2 (p=0.037), but LV mass-volume ratio remained unaffected by the exercise program.
"There are several possibilities why a year of training failed to improve LV compliance in sedentary seniors," say the researchers in the journal Circulation.
They cite the late age at which the program was initiated as one explanation, and say that by the age of 65 years, irreversible cross linking of advanced glycation end products in the ventricles may lead to irreversible LV stiffening.
Levine and team state that further research is required to determine the age in later life at which exercise training can be started and still benefit LV compliance.
They conclude: "The present results could constitute an important step for the development of optimal training programs or adjunctive therapies in seniors with and without CV disease."
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By Lauretta Ihonor