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 Compared to sedentary peers, the older adults in the
study who were active had better heart-rate variability – a measure
of the slight differences in time between each heartbeat that is
influenced by the health of both the heart and the nervous system.
“Modest physical activity, such as the distance and pace of walking,
is important for the heart’s electrical well being of older adults,”
Luisa Soares-Miranda told Reuters Health in an email.
The effects were seen over time, added Soares-Miranda, a researcher
at the Harvard School of Public Health in Boston and the Faculty of
Sport at the University of Porto in Portugal who led the new
research.
“In our study, older adults that increased their walking pace or
distance had a better heart rate variability when compared with
those that decreased their walking pace or distance,” she said.
Heart rate variability is a sign of a healthy heart that can respond
readily to changing demands and is often used as a measure of
fitness for adults of any age.
Previous research has shown a link between exercise, heart rate
variability, and lowered cardiovascular risk in groups of
middle-aged people, but little is known about whether those ties
persist in older adults, the researchers note in the journal
Circulation.
Soares-Miranda and her colleagues analyzed data on nearly 1,000
participants in the Cardiovascular Health Study that began in the
U.S. in 1989. The men and women were 65 or older at the beginning of
the study and were followed for five years.
Study participants were initially evaluated for their health status,
medical history and cardiovascular risk factors, and asked about
their usual amounts of physical activity, including sports and
everyday activities such as gardening, housework and walking.
All the people included in the new analysis had their heart rate
variability tested at the beginning and end of the five-year study
period.
When the researchers analyzed the data, they divided participants
into five groups representing the lowest to the highest amounts of
physical activity and found that people in the top fifth also had
the most favorable heart-rate variability results.
That was particularly true for those who increased their walking
pace or distance over the five years studied.
The results don’t prove that the exercise influenced heart rate
variability, but the researchers adjusted for several factors,
including weight, overall health, use of heart drugs or presence of
diabetes, to see if people with the healthiest hearts were the most
likely to engage in physical activity.
The results held, and based on other large studies, Soares-Miranda
and her team calculated that participants who were the most active
had about 11 percent less risk of cardiovascular disease compared to
participants who were the least active.
“Our results suggest not only that regular physical activity later
in life is beneficial, but also that certain beneficial changes that
occur may be reduced when physical activity is reduced,” Soares-Miranda
said.
She also said the study findings support the need to maintain modest
physical activity throughout the aging process.
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“Even small increases can lead to a better health, while reducing
physical activity has the opposite effect,” she said. “So, any
physical activity is better than none, and more is better.”
Walking is the most common form of activity, Soares-Miranda said,
and she believes it’s a good way to achieve physical activity
recommendations for aerobic exercise.
“I think that if a senior feels comfortable with his or her usual
physical activity -- independently of what the activity is, he or
she should not slow down,” Soares-Miranda said. “If walking is the
main physical activity, try to walk an extra block or walk at a
faster pace. It is never too late to start and to do more.”
Dr. Michael Rich said that normal heart rate variability typically
declines with age and can be partly due to diseases people develop
or to physical deconditioning.
Rich is director of the Cardiac Rapid Evaluation Unit of the
Barnes-Jewish Hospital in St. Louis and was not involved in the new
research.
“I think what this study shows is that despite what we know about
changes in heart rate variability with age, there still is an
association between physical activity and heart rate variability
that is favorable and that people who exercise regularly have a more
favorable profile of different heart rate variability,” he told
Reuters Health.
“What the authors are trying to imply, but can’t actually prove in
this study, is that the favorable effect of exercise on heart rate
variability might be part of the mechanism for – or at least
contribute to the general association between – good physical
conditioning, regular physical activity and health in general, and
risk for cardiovascular diseases in particular, such as heart
attack, and congestive heart failure,” he said.
Rich, who is a cardiology researcher with Washington University in
St. Louis and a spokesperson for the American Geriatrics Society,
added that more research on the oldest seniors would be beneficial.
“The average age of the population of this study was 71, so it's a
relatively young older population and whether the findings are
applicable in people over 80, I think we don't know from the study,”
he said. “It would be interesting to do a similar type of analysis
on a population of people over the age of 80.”
SOURCE: http://bit.ly/1sgUhTM Circulation, online May 5, 2014.
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