"A critical weekly review of important new research findings for health-conscious readers..."
By, Robert A. Wascher, MD, FACS
The information in this column is intended for informational purposes only, and does not constitute medical advice or recommendations by the author. Please consult with your physician before making any lifestyle or medication changes, or if you have any other concerns regarding your health.
STRESS, HEART DISEASE, EXERCISE & DEATH
Multiple prior clinical research studies have identified a link between high levels of stress and the risk of death in patients with coronary artery disease (CAD).
Aerobic exercise training is a standard component of rehabilitation programs for patients with CAD. A properly supervised exercise training program for patients with CAD, including patients who have suffered a heart attack, has been shown to reduce the risk of CAD-related death. At the same time, it is also well known that regular aerobic exercise can also help patients to better cope with high levels of personal stress, and also improves the symptoms of depression and other mental health disorders, as well.
An intriguing clinical research study, newly published in the American Journal of Medicine, evaluated the impact of exercise training on the risk of death in patients with CAD. The two “experimental” groups of patients included 53 patients with CAD who reported high levels of stress in their lives, and 369 patients with CAD who reported low stress levels in their personal lives. These two groups of patients participated in a cardiac rehabilitation program that included formal aerobic exercise training. A “control” group of 27 patients with CAD was also included in this research study, and these control patients also reported high levels of stress in their lives. However, unlike the experimental group patients, this control group of patients did not undergo cardiac rehabilitation, or any other form of supervised exercise training. The subsequent findings of this clinical research study were rather dramatic.
Overall, the risk of death among the patients with CAD who reported high levels of stress was a whopping 4 times greater than the mortality rate of the patients with low levels of stress in their lives (22 percent vs. 5 percent, respectively).
As has been shown in previous clinical studies, regular aerobic exercise appears to decrease self-reported stress levels. In this study, the percentage of patients reporting severe levels of stress declined from 10 percent, at the beginning of the study, to 4 percent, by the end of the study, among patients who underwent formal exercise training.
Perhaps the most interesting finding from this study was that patients who increased their total exercise capacity by at least 10 percent also lowered their risk of death by a rather amazing 60 percent when compared to patients who achieved a less than 10 percent improvement in exercise capacity. Moreover, among the patients who reported high levels of stress in their lives, the risk of dying during the course of this clinical study was dramatically reduced in the group of patients who were able to increase their prior exercise capacity by at least 10 percent. In fact, while 19 percent of the “highly stressed” patients who achieved little or no improvement in their exercise capacity died during the course of this study, none of the “stressed” CAD patients who managed to increase their exercise capacity by at least 10 percent died. On the other hand, CAD patients reporting low levels of personal stress did not appear to experience any significant improvement in mortality risk whether they achieved a high level of exercise capacity improvement or a low level of exercise capacity improvement.
The results of this study suggest that (as has previously been shown) a high level of personal stress is independently associated with an increased risk of dying from preexisting CAD. A second finding of this study, which has also been confirmed by other studies, is that self-perceived levels of stress can be significantly reduced with regular aerobic exercise. The most interesting and novel finding of this study, however, is that exercising at a level that increases one’s exercise capacity by at least 10 percent appears to be a potentially powerful way of reducing the increased mortality risk that is associated with chronically elevated levels of personal stress in patients with CAD.
One potential limitation of this clinical study is that it is not entirely clear how well the patients in each group were matched in terms of the severity of their CAD (as well as other chronic illnesses, including mental health and personality disorders). For example, at least some of the experimental group patients who were unable to improve their exercise capacity by at least 10 percent may have been unable to do so due to the presence of serious illnesses (including more severe heart disease) that limited their ability to exercise. In such cases, the increased risk of mortality observed in this study may have been directly caused by the presence of more serious illnesses in these patients, when compared to the patients who were able to more dramatically improve their exercise capacity. However, as most of the findings of this clinical research study are consistent with larger and better controlled previous studies, it is very likely that there is some validity in its more novel conclusions (and, most notably, that vigorous and regular aerobic exercise may directly reduce stress-related physiological factors that increase the risk of dying from CAD).
Prior to embarking on a new or more vigorous exercise program, I advise that you first be evaluated by your personal physician, especially if you have CAD or other serious illnesses. (For an in-depth overview of the benefits of exercise on cancer prevention, look for the publication of my new book, “A Cancer Prevention Guide for the Human Race,” in the spring of 2010.)
Disclaimer: As always, my advice to readers is to seek the advice of your physicianbeforemaking any significant changes in medications, diet, or level of physical activity
Dr. Wascher is an oncologic surgeon, a professor of surgery, a widely published author, and a Surgical Oncologist at the Kaiser Permanente healthcare system in Orange County, California
(Anticipated Publication Date: March 2010)
(Click above image for TV36 interview of Dr. Wascher)