If you're fit in middle age, you might be guarding against not only depression as a senior, but also dying from heart disease if you do develop depression, a new study suggests.
Among nearly 18,000 Medicare patients, the most fit were 16 percent less likely to develop depression, the researchers found. The most fit were also 56 percent less likely to die from heart disease if they developed depression, and 61 percent less likely to die from heart disease if they remained free of depression.
"There is a well-known connection between depression and cardiovascular disease," said lead researcher Dr. Benjamin Willis, an epidemiologist at the Cooper Institute in Dallas.
People with heart disease are at greater risk for depression, and people who are depressed are at greater risk of a heart attack in later life, he said.
Willis added that this was an observational study, so it can't prove being fit prevents depression or that fitness lowers the risk of dying from heart disease if one is diagnosed with depression.
Dr. Satjit Bhusri, a cardiologist at Lenox Hill Hospital in New York City, said, "Patients should know, however, that depression and fitness are not only intertwined, but also can result in organic changes in their risk of developing heart disease." Bhusri was not involved in the new study.
Willis pointed out that fitness can reduce the risks of both depression and heart disease even over long periods of time.
But only 50 percent of Americans meet the minimum guidelines for aerobic activity -- 150 minutes of exercise a week, Willis said.
The good news is that the benefits of exercise kick in regardless of how old you are when you start, he added.
"It is never too late to get off the couch," Willis said. Examples of moderate to vigorous activity include walking, jogging, swimming and cycling.
"Always consider your own health status and check with your physician before embarking on a new physical activity program," he cautioned.
For the study, Willis and his colleagues collected data on 17,989 healthy men and women, average age 50, who visited a clinic for a preventive medical exam when they were middle-aged. The data were collected from 1971 through 2009. Study participants were eligible for Medicare from 1999 to 2010.
The researchers estimated fitness from treadmill exercise tests, depression from Medicare claims files, and heart disease deaths from the U.S. National Death Index records.
Because the diagnoses of depression came from Medicare claims, how severe the depression was could not be determined.
Dr. Scott Krakower is assistant unit chief of psychiatry at Zucker Hillside Hospital in Glen Oaks, N.Y. He said, "What we are learning more and more is that exercise is a potent antidepressant."
Exercise may not only help you with heart health, but also with "mental health, overall happiness and well-being," Krakower added.
The report was published online June 27 in the journal JAMA Psychiatry.
For more on exercise and health, visit the Harvard Business Review.
This content is intended for informational purposes only. It should not replace professional medical advice, diagnosis, or treatment. If you think you have a medical emergency, call 911 or your doctor immediately.