Increasing age is associated with substantial changes in cardiovascular structure and
function, the cause and permanence of which are unknown. Diastolic function in
particular alters appreciably in older adults but non-invasive measurement of cardiac
function during diastole has significant limitations. Magnetic resonance imaging with
tagging was used to identify changes in three dimensional myocardial strain in older
compared to young normal volunteers. This technique identified significantly
delayed myocardial relaxation with more myocardial strain persisting in early
diastole in older compared to younger individuals. These findings were thought to be
attributable to the aging process.
Epidemiological studies and small, non-randomised trials suggest that physical
activity might slow cardiovascular aging and improve diastolic function in older
adults. A randomised controlled trial was therefore performed to assess whether
exercise training could modify age-related changes in older, normal volunteers who
had been screened to exclude significant cardiovascular disease. The intervention
group underwent six months of supervised exercise training whilst participants in the
control group were asked to maintain their pre-trial levels of activity. Measurements
made at baseline and after six months included transthoracic echocardiography,
cardiac MRI, body composition, blood lipid concentrations, applanation tonometry,
quality of life and maximal exercise capacity.
Despite significant increases in exercise capacity in the intervention group, no other
significant changes in cardiovascular structure or function, body composition,
cholesterol concentration or quality of life were observed when compared to changes
seen in the control group.
Six months of exercise training in previously sedentary older adults are insufficient
to modify cardiovascular function and structure despite causing marked improvements in exercise capacity. These findings contrast with previously reported
non-randomised trials of exercise training in older people. However, they add
important, robust information regarding the likely effects of short periods of exercise
training on cardiovascular function and structure in older normal adults.