Over half a million cases are diagnosed each year.
Despite its name, "heart failure" does not mean that the heart has stopped working completely, explain the American Heart Association (AHA).
In congestive heart failure, the heart is not pumping blood as well as it should be.
Heart failure occurs in two main ways: either the muscles of the heart weaken, or they become stiff and lose their elasticity.
Although the condition affects people of all ages, it is more prevalent among seniors over the age of 60. The AHA recommend that people at risk avoid smoking, exercise more, and eat heart-healthy foods.
A new study delves deeper into one of these potential strategies for prevention. Researchers from the University of Buffalo in New York set out to investigate how walking affects two heart failure subtypes: reduced ejection fraction heart failure, and preserved ejection fraction heart failure.
Michael LaMonte, a research associate professor of epidemiology at the University of Buffalo School of Public Health and Health Professions, led the study.
Studying walking and heart failure in women
Reduced ejection fraction heart failure occurs when the heart's left side pumps less blood into the body than normal.
Specifically, the normal ejection fraction — which measures how much blood is pumped out of the left ventricle into the body in one heartbeat — is over 55 percent. In reduced ejection heart failure, this rate drops to 40 percent or under.
In preserved ejection fraction heart failure, this rate may be over 50 percent and thus appear to be normal. However, if the heart muscles are too thick or stiff, the initial amount of blood that the ventricles can hold may already be too small for what the body needs.
As LaMonte and team explain, the first form of heart failure has a poorer outlook, whereas the second form is more common in seniors and tends to affect women and ethnic minorities in particular.
The researchers examined the link between physical activity levels as reported by 137,303 people who registered in the Women's Health Initiative, a long-term study of postmenopausal women.
Then, the scientists zoomed in on a subgroup of 35,272 women who lived with either one of the two subtypes of heart failure.
Why walking is 'particularly important'
For each additional 30–45 minutes of daily physical activity, the risk of developing heart failure was reduced by 9 percent for heart failure in general, by 8 percent for preserved ejection fraction heart failure, and by 10 percent for reduced ejection fraction heart failure.
Crucially, while walking and physical activity correlated inversely with heart failure risk, the intensity of the physical activity did not have any effect; this suggests that the amount of activity is what matters.
"The finding that walking showed a protective association with heart failure and its subtypes is particularly important in a public health context. This is especially relevant given that walking is by far the most commonly reported physical activity in older adults."
"This is the first study to report physical activity levels are related to a lower risk of developing heart failure with reduced ejection fraction in older adults, particularly in women," highlights LaMonte.
"This is pretty important from a public health standpoint, given the poor prognosis this type of heart failure has once it's present," he adds.
"Because heart failure is much more common after age 60," he says, "and because its treatment is very challenging and costly, the possibility of preventing its development by promoting increased physical activity levels, and specifically walking, in later life could have an important impact on the overall burden of this disease in an aging society."