By Beth Israel Deaconess Medical Center Correspondent

We all know that exercise is good for the heart, right? But, knowing something doesn’t always make it happen. It can much easier to kick the can down the road and worry about heart health only if it becomes a problem. But, a new study from researchers at Beth Israel Deaconess Medical Center (BIDMC) and the University of Michigan, Ann Arbor offers surprising insights that might help you rethink that strategy.

(Photo: iStockphoto)

(Photo: BIDMC/Shutterstock)

The study published recently in JAMA Internal Medicine shows just how early the relationship between exercise and long-term heart health begins. The investigators looked at measures of cardiorespiratory fitness in adults as young as 18 years of age and found that fitness was associated with a substantially lower risk of dying or developing cardiovascular disease (CVD) more than 25 years later.

“We typically start formally assessing cardiovascular health and risk of disease in otherwise healthy patients as they approach middle age,” said co-lead author Ravi V. Shah, MD, a cardiologist in BIDMC’s CardioVascular Institute and an Instructor in Medicine at Harvard Medical School. “This is one of the first large studies to examine people in their twenties over such a long period, and the findings suggest that if we want to address cardiovascular disease at its earliest stages, we really should be targeting younger individuals.”

Shah and colleagues analyzed data from the Coronary Artery Risk Development in Young Adults (CARDIA) study sponsored by the National Institutes of Health. The study included 4,872 racially-diverse adults (ages 18 to 30) who underwent a standard treadmill cardiac stress test at baseline between March 1985 and June 1986. Half of those individuals had a second stress test seven years later. Participants were assessed for obesity, left ventricular heart mass and strain (a measure of the strength of heart muscle contraction), coronary artery calcification and incident CVD.

The exercise treadmill stress test in the study consisted of up to nine two-minute stages of gradually increasing difficulty. Participants were tested to see how many stages they could endure. The study suggests that each additional minute of endurance at baseline was associated with a 15 percent lower risk of death and a 12 percent lower risk of CVD. Each one-minute increase was also associated with reduced left ventricular mass and better strain scores.

The second treadmill assessment seven years later suggests that a one-minute reduction in stress test endurance by year seven was associated with a 21 percent increased risk of death and a 20 percent increased risk of CVD.  Each one-minute reduction was associated with worsening strain scores.

“Importantly, we found that the benefits of fitness were not dependent on weight, which suggests that being fit is important for everyone, not only for people who are trying to lose or to maintain weight,” said Shah.

Surprisingly, the researchers found that cardiorespiratory fitness was not associated with the development of coronary artery calcification, a widely used measure for early coronary artery disease.

“The findings suggest that the biological relationship between exercise and heart health is complex and that any one test – including measures for coronary artery calcification – may not sum up the entire picture of a person’s heart health. Fitness in early adulthood may prevent disease in ways that do not involve calcification of the arteries,” said Venkatesh Murthy, MD, PhD, Assistant Professor of Medicine, University of Michigan, Ann Arbor. “The big take away is that efforts to evaluate and improve fitness at an early age have the power to affect long-term heart health.”

Above content provided by CardioVascular Institute at Beth Israel Deaconess Medical Center. For advice about your medical care, consult your doctor.

Posted February 2016