Exercise is not enough to protect heart against stress

Teens who have trouble coping with stress may face an increased risk for future heart trouble that even exercise can't erase, a new study suggests.

"It looks like the inability to cope well with stress contributes to the risk of heart disease," said lead researcher Scott Montgomery, a professor of epidemiology at Orebro University in Sweden.

Montgomery said what he found "striking" was that physical fitness did not protect teens with poor stress-coping skills from developing heart disease later in life.

"Exercise is important," Montgomery said. "But maybe we have to think about exercise and physical fitness in the context of coping with stress, particularly with people who have had a heart attack."

For these people, both exercise and developing strategies to reduce stress might be needed to prevent more heart problems, Montgomery said.

But one expert noted that the study only involved males and only measured stress-coping skills once.

For those teens in the study who struggled with stress, also known as low stress resilience, the risk for heart disease increased by 54 percent and the risk of dying from heart disease increased 110 percent.

"Not only are you more likely to have a heart attack, but you are more likely to have a severe heart attack," Montgomery said.

He noted that low stress resilience isn't something one is born with. "Experiments in animals suggest that exposures to stress very early in life influence our ability to cope with stress. If we have a lot of very early stress, we are less able to cope with it later on," Montgomery explained.

For people with low stress resilience, even minor events can be extremely stressful, and the effects will last longer than among people better able to cope, Montgomery said.

"We know from other studies that very stressful events can cause heart attacks. If you have a low stress resilience and something more serious happens, it can have injurious consequences to the heart," he said.

The report was published online March 4 in the journal Heart.

For the study, Montgomery and colleagues collected data on almost 238,000 men born between 1952 and 1956 who were included in the Swedish Military Conscription Register.

At the time, military service was compulsory for all men aged 18 and 19. Men underwent an examination that included medical, psychiatric and physical measures. Stress resilience was measured as part of the exam.

Between 1987 and 2010, more than 10,500 of the men developed heart disease. The researchers found that low stress resilience was tied to a higher risk of heart disease. This association remained even after taking into account physical fitness and other risk factors for heart disease, although the study did not prove a cause-and-effect link.

Simon Rego, director of psychology training at Montefiore Medical Center/Albert Einstein College of Medicine in New York City, said that there are several limitations to the study.

First, it included only Swedish men, which limits the "generalizability" of the results, he said. "Second, stress resilience was only measured once and stressful exposures were not actually examined at all," Rego said.

Researchers, clinicians and health care professionals should continue to promote physical activity as a way to help prevent both physical and mental ills, he said.

But it may also help if stress-management skills were taught to teens along with promoting exercise, Rego added.