Depression has long been associated with cardiac problems. We know, for instance, that people who are physically healthy but depressed are more likely to develop cardiovascular disease… that being depressed puts people who already have heart disease — including those who have had a heart attack or bypass surgery — at higher risk for recurrence of a cardiac event… and that people who are depressed after a cardiac event are at greater risk for death within the next few years. What we haven’t known until now is why.
A recent study, published in the Journal of the American Medical Association, identified a critically important factor explaining this link: lack of exercise. Researchers followed 1,017 outpatients with stable coronary heart disease for nearly five years and were surprised to discover that physiological changes (elevated cortisol and norepinephrine, for example) were not responsible for the increased risk of cardiac events associated with depression. Instead, the researchers discovered that the increased rate of cardiovascular events in depressed patients has more to do with physical inactivity. The study team found that lack of exercise was associated with a 44% greater rate of cardiovascular events. After accounting for lack of exercise and other health behaviors (such as medication non-adherence and smoking), depression by itself was no longer associated with an increased risk of cardiovascular events. The current study reveals that the sedentary habits of depressed individuals creates a cycle of depression and poor cardiac health.
I called an expert in the matter of cardiovascular disease and exercise, Gordon Blackburn, PhD, program director of Cardiac Rehabilitation at the Cleveland Clinic, to ask about his thoughts on the study. Dr. Blackburn told me that many patients experience some level of depression after a heart attack. Many go on to develop a new attitude, becoming invigorated about the process of a new, healthier lifestyle, but even a mild and transient bout of depression can increase the risk of future cardiac problems.
Making matters worse, Dr. Blackburn said that those with depression tend to not be compliant with other lifestyle or management strategies such as medications, nutrition guidelines or follow-up medical care. Clearly all these factors contribute to a worsening of heart disease, putting people at higher risk, notes Dr. Blackburn.
There is a solution to this problem. Cardiac rehabilitation programs, which are part of follow-up care for months after cardiac surgery or a heart attack at many hospitals, get patients up and moving with a regular exercise routine. Unfortunately, only about 20% of eligible patients participate, even though these programs are covered by many insurance companies and Medicare. If more patients did take part, Dr. Blackburn says, their health would improve in a variety of ways, all of which would help them feel better and live longer.
Dr. Blackburn told me he is disturbed that some patients assume cardiac procedures or bypass surgery will fix their heart problems. Heart disease continues, he says, and if patients don’t address their risk factors, it will surely progress. Doctors have not routinely focused on depression as a significant issue with cardiac patients, says Dr. Blackburn, but perhaps the results of this study may change this. Regular screening for depression would show health care teams which patients need treatment for it, as well as underscore for patients the importance of a cardiac exercise program that could help save their lives.
