Regimen needs to begin before age 65, researchers say
DALLAS – January 8, 2018 — Exercise can reverse damage to sedentary, aging hearts and help prevent risk of future heart failure — if it’s enough exercise, and if it’s begun in time, according to a new study by cardiologists at UT Southwestern and Texas Health Resources.
To reap the benefits, the exercise regimen needs to begin before age 65, while the heart apparently retains some plasticity and ability to remodel itself, according to the findings by researchers at the Institute for Exercise and Environmental Medicine (IEEM), which is a collaboration between Texas Health Presbyterian Hospital Dallas and UT Southwestern Medical Center.
And the exercise needs to be performed four to five times a week. Two to three times a week was not enough, researchers found.
“That’s my prescription for life. I think people should be able to do this as part of their personal hygiene – just like brushing your teeth, taking a shower, changing your underwear,” said senior author Dr. Benjamin Levine, director of the IEEM and professor of Internal Medicine at UT Southwestern and holder of the Finley Ewing Chair for Wellness and the Harry S. Moss Heart Chair for Cardiovascular Research at Texas Health Dallas.
The regimen followed included exercising four to five times a week, generally in 30-minute sessions, plus warmup and cool-down sessions.
- One of the weekly sessions included a high-intensity 30-minute workout, such as an aerobic interval sessions in which heart rate tops 95 percent of peak rate.
- One session lasted an hour and was of moderate intensity, such as tennis, aerobic dancing, walking, or biking.
- Two weekly strength training sessions used weights or exercise machines.
- Low-intensity exercise was performed on the other days.
- Study participants built up to those levels, beginning with three, 30-minute, moderate exercise sessions for the first three months.
The more than 50 participants in the study were divided into one group that received two years of supervised exercise training and a control group that participated in yoga.
At the end of the two-year study, those who had exercised showed an 18 percent improvement in their maximum oxygen intake during exercise and more than a 25 percent improvement in compliance, or elasticity, of the left ventricular muscle, Levine noted. He compared the change to a stretchy, new rubber band versus one that has gotten stiff sitting in a drawer.
Aging can lead to a stiffening of the muscle in the heart’s left ventricle, the chamber that pumps oxygen-rich blood back out to the body.
“When the muscle stiffens, you get high pressure and the heart chamber doesn’t fill as well with blood. In its most severe form, blood can back up into the lungs. That’s heart failure,” said Levine, who holds the Distinguished Professorship in Exercise Sciences at UT Southwestern, which is celebrating its 75th anniversary this year.
Earlier research by UT Southwestern cardiologists showed that left ventricular stiffening often shows up in middle age in people who don’t exercise and aren’t fit, leaving them with small, stiff chambers that can’t pump blood as well.
However, the researchers also found that the heart chamber in competitive Masters-level athletes remains large and elastic, and that even four to five days of committed exercise over decades is enough for others to reap most of this benefit.
In the current study, researchers wanted to know if exercise can restore the heart’s elasticity in previously sedentary individuals — and how late in life such a reversal might be possible.
To find out, researchers recruited 53 participants, aged 45 to 64. Many came from the Dallas Heart Study, which includes 6,000 Dallas residents and is the only single-center heart study of its size and multiethnic composition. The Dallas Heart Study is designed to improve the diagnosis, prevention, and treatment of heart disease.
The study appears in Circulation, a journal of the American Heart Association. Collaborators on the study included first author Dr. Erin Howden, Research Fellow with UT Southwestern’s Graduate School of Biomedical Sciences and the IEEM, along with researchers from the Baker Heart and Diabetes Institute in Melbourne, Australia; Stanford University; and the University of Colorado Anschutz Medical Campus. Funding came from the National Institutes of Health and the American Heart Association.
About the IEEM
The Institute for Exercise and Environmental Medicine (IEEM) at Texas Health Presbyterian Hospital Dallas is among the most sophisticated human physiology laboratories in the world. IEEM researchers explore and define the limits and capacities of the human body. IEEM research and patient programs help to establish treatments and contribute to the development of cures for many of society’s most debilitating and chronic diseases including; hypertension, diabetes, congestive heart failure, Alzheimer’s disease, Obstructive Sleep Apnea (OSA), and obesity.
About UT Southwestern Medical Center
UT Southwestern, one of the premier academic medical centers in the nation, integrates pioneering biomedical research with exceptional clinical care and education. The institution’s faculty has received six Nobel Prizes, and includes 22 members of the National Academy of Sciences, 18 members of the National Academy of Medicine, and 14 Howard Hughes Medical Institute Investigators. The faculty of more than 2,700 is responsible for groundbreaking medical advances and is committed to translating science-driven research quickly to new clinical treatments. UT Southwestern physicians provide care in about 80 specialties to more than 100,000 hospitalized patients, 600,000 emergency room cases, and oversee approximately 2.2 million outpatient visits a year.
SOURCE: Texas Health