Depression of the Heart

Whether or not you are depressed will affect your exercising success. For many who believe that exercise is an alleviator for the symptoms of depression this may come as a shock. Yes, exercise still does alleviate some of these symptoms but physiologically there is also something else going on that could contribute to a shorter lifespan.

In our first Physiology lecture we learned that long-term disruptions in homeostasis, such as stress, may be detrimental to our health due to the fact that our body is not created to deal with long-term physical stressors. An extended period of depression or extreme stress is likely to cause illness – mental or physical. What does this mean when we are already in such a stressed state and exercising on top of that? This combination of physical and mental stress has been investigated in several scientific studies.

As shown by a study at Duke University Medical Center in 1996 there is an undisputable link between depression and heart disease, specifically myocardial infarction. The study showed that people with chronic psychological stress have an increased risk of heart attack. Emphasis must be put on the fact that this stress is classified not as an episodic condition but a chronic one. Another study found that the level of depression for patients admitted with myocardial infarction is significant in determining their long-term survival. Those with moderate to severe levels of depression are less likely to recover the cardiovascular mechanisms, which lead to cardiac mortality. Thus, these patients will die sooner than their less stressed counterparts.

So how exactly does depression hinder the effects of exercise? Depression has been found to prolong the amount of time it takes for the heart rate to recover in a depressed patient after exercising. These effects were seen in a new study done at the Montreal Heart Institute in Canada. The study consisted of 866 healthy adults with 51 of these adults being diagnosed with severe depression. The subjects were given stress tests while exercising on a treadmill and their blood pressure and heart rates were measured throughout. It took notably longer for those suffering from depression to slow down their heart rates to normal; the difference was about 3.7bpm. Although a difference of a few beats per minute during post-exercise recovery may seem insignificant it has been linked with a shorter life span.
A similar study done at Stanford showed that men who died during their follow-up period had also experienced longer heart recovery rates in the study. These men had a difference of about 3bpm in recovery.

This effect on heart function has caused many scientists and doctors to believe that people suffering from sever depression may have a dysfunctional stress response. The nervous system should go back to normal quite quickly after experiencing a stressor but in these patients that is not the case and, as stated by Dr.Bacon, “the circuitry of the brain that causes the stress response becomes dysfunctional.” This does not mean, however, that people with depression should not exercise, in fact, regular exercise may even improve their recovery heart rate. For future investigations further attention is being given to any treatment, including behavioral therapy or drugs, that may be able to improve this stress response.


References:

http://well.blogs.nytimes.com/2011/12/01/depression-may-slow-exercise-recovery/?ref=health

Barefoot, J. and M. Schroll. “Symptoms of depression, acute myocardial infarction, and total mortality in a community sample.” Circulation. 93(11): 1976-80. 1996.

Gordon, J., B. Ditto, K. Lavoie, R. Pelletier, T. Campbell, A. Arsenault, and S. Bacon. “The effect of major depression on postexercise cardiovascular recovery.” Psychophysiology. 48(11):1605-10. 2011

Lesperance, F., N. Frasure-Smith, M. Talajic, and M. Bourassa. “Five-year risk of cardiac mortality in relation to initial severity and one-year changes in depression symptoms after myocardial infarction.” Circulation. 105(9): 1049-53. 2002.

Shetler, K., R. Marcus, V. Froelicher, S. Vora, D. Kalisetti, M. Prakash, D. Do, and J. Myers. “Heart rate recovery: validation and methodologic issues.” Journal of the American College of Cardiology. 38(7): 1980-7. 2001.