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Texas Health Presbyterian Hospital Dallas Researchers Discover That Lifelong Exercise Keeps the Heart Young, Strong|
DALLAS — Researchers at the Institute for Exercise and Environmental Medicine at Texas Health Presbyterian Hospital Dallas have found that consistent lifelong exercise can make heart muscle in the elderly as healthy — even healthier — than the heart muscle of young sedentary people.
The scientists found that being physically active throughout life prevents declines in heart muscle commonly associated with aging. Those losses in heart muscle can lead to heart failure, one of the leading causes of death and disability in the United States.
“The message is that our hearts don’t have to lose muscle and weaken as we age,” said Dr. Benjamin Levine, director of the IEEM and professor of medicine and cardiology and a distinguished professor in exercise science at UT Southwestern Medical Center. “And you don’t have to run marathons or be a competitive tri-athlete to see the benefits.”
“Consistent (and committed) exercise at least 4-5 times a week that increases the heart rate, even if it’s walking or bike riding, can translate to better health now — and later in life,” he added. The findings were recently presented at the annual scientific meeting of the American College of Cardiology in New Orleans.
Levine’s team found that regular, lifelong physical activity preserves the elasticity of the heart, which is vital for efficient pumping of blood throughout the body. The heart is typically elastic in younger people, especially among those who exercise regularly. But for people who do not exercise and are sedentary, the heart loses that elasticity and muscle mass as they age.
“What’s most fascinating is that elderly people who have a history of exercise throughout adulthood maintain the mass of their heart muscle and can even build upon it,” Levine said. “Those who exercise regularly, six to seven times a week, can have a heart that functions as well as someone in their 20s who is sedentary.”
Scientists have long known that a common side effect of aging is loss of skeletal muscle mass. Now, the IEEM team has shown that there’s similar decline in heart muscle mass and its flexibility, or compliance, which can cause a host of serious medical conditions, said Dr. Paul Bhella, a former researcher at the IEEM who is now a practicing physician in Fort Worth.
The study enrolled 121 healthy people with no history of heart disease; about 100 longtime exercisers, all over 65, were recruited in collaboration with the Cooper Clinic based on documentation that they had exercised consistently for at least 25 years. Study subjects were broken into four groups: non-exercisers; casual exercisers (two to three times a week); committed exercisers (four to five times a week) and Masters athletes (six to seven times a week).
Using MRI tests, scientists measured the mass of each subject’s left ventricle. The results showed that non-active (sedentary) subjects experienced a decline in left-ventricle heart mass as they aged. Lifelong exercisers, on the other hand, increased their heart mass the more frequently they exercised. On a separate day, the researchers inserted catheters into right side of the volunteers’ hearts to measure its pressure and compliance.
“The data suggest that if we can identify people in middle age, in the 45 to 60 year range, and get them to exercise four to five times a week, this may go a very long way in preventing some of the major heart conditions of old age," Levine said.
Researchers measure left ventricle mass because that chamber is the “power plant” of the heart. The left ventricle provides the power stroke that pumps oxygenated blood at high pressure to tissue and organs throughout the body. The right ventricle of the heart, on the other hand, pumps blood to the lungs for re-oxygenation. Problems with that chamber don’t always cause life-threatening problems. Compromised pumping power in the left ventricle, though, depletes vital organs of oxygen and threatens multiple systems, causing everything from kidney failure to fluid buildup in the lungs to circulations problems in extremities. Increased stiffness of this chamber causes blood to back up into the lungs causing shortness of breath and exercise intolerance.
The mass of the left ventricle typically peaks early in life and diminishes with sedentary aging. With less left ventricular heart mass, people are susceptible to cardiac events, including diastolic heart failure, a common form of heart failure in the elderly.
The findings by the IEEM team also call into question current definitions for what is considered “normal” and “abnormal” heart mass for healthy people. Researchers say they are optimistic that their findings will help to remind physicians and their patients that exercise can directly impact heart mass and redefine normal ranges that will take into account how much physical activity people have done throughout their adult life.
“Defining how to intervene at the right time and with the right dose [of physical activity] are critical questions we need to answer both from a public health standpoint, but also as cardiologists we want our patients to remains healthy and forestall heart problems,” Levine said.
The study was sponsored/funded by the National Institutes of Health.
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