|
 Participants with the greatest improvements in their cardio fitness
were less burdened by symptoms of the arrhythmia, known as atrial
fibrillation, and more likely to survive symptom free during the
study, compared to those who had smaller or no fitness improvements.
A possible side effect of the cardio exercise regimen, weight loss,
may have also contributed to the improvements, researchers say.
Obesity is a risk factor for heart rhythm problems, said the study’s
lead author Prash Sanders, director of the Center for Heart Rhythm
Disorders at Royal Adelaide Hospital. And “atrial fibrillation (AF)
is a growing epidemic,” he told Reuters Health in an email.
In atrial fibrillation, the heart beats rapidly and irregularly,
which can promote the formation of clots and cause problems with
blood flow. The condition, sometimes known as A-Fib or AF, affects
more than 33 million people worldwide, Sanders and colleagues write
in the Journal of the American College of Cardiology.
While weight loss has been shown to help with heart rhythm issues,
the study team wanted to determine how cardio fitness might benefit
overweight people struggling with heartbeat irregularities.
At the start of the study and four years later, 308 overweight and
obese volunteers with atrial fibrillation complete questionnaires
that asked how often they experienced heartbeat irregularities, how
long the episodes lasted and how severe they were.
The researchers also had patients wear a heart monitor for seven
days at a time.
Based on exercise stress testing at the start of the study, 95
people were classified as having low cardio fitness, 134 had
adequate fitness and 79 were classified as high fitness.
The amount of exercise effort these participants could manage was
described in units known as Metabolic Equivalent of Task (MET). For
instance, five METs is about as strenuous as walking up a flight of
stairs. Jogging is equal to about seven METs and walking to about
three.
The research team prescribed the patients an exercise program
tailored to their age and physical ability, which gradually
increased in intensity.
By the end of four years, those who had increased their fitness
levels by two METs or more, and those who lost weight were more
likely to have reduced or no AF symptoms than those who improved by
less than two METs or not at all.
[to top of second column] |
Dr. Michael Lloyd, a cardiologist at Emory University Hospital in
Atlanta, Georgia, noted in an email that cardiorespiratory fitness
is defined as how much oxygen your heart and lungs can deliver to
your muscles.
Though increasing cardio fitness seems to be beneficial, Lloyd, who
was not involved in the study, advises caution. “Overweight people
should check with their doctor prior to embarking on any exercise
program,” he said.
Sanders recommends a tailored exercise program, “in which
consideration for age and physical ability should be made so that
targets are achieved without risking injuries.”
Dr. Waqas Qureshi, a cardiology researcher at Wake Forest University
in Winston-Salem, North Carolina, who also was not involved in the
study, noted that weight loss from exercise may add to the
protection against heart irregularities.
Lloyd, however, emphasized that cardio fitness is beneficial even
apart from weight loss. “If you are overweight, it's not just the
pounds that matter, it's how fit you are. This study shows that
increasing your fitness through exercise and lifestyle choices does
reduce your chance of having the most common arrhythmia.”
SOURCE: bit.ly/1HBnrTr Journal of the American College of
Cardiology, online June 22, 2015.
[© 2015 Thomson Reuters. All rights
reserved.] Copyright 2015 Reuters. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed.
 |
