Thank you for asking this interesting question. I am a physician and
will use only objective, physician-written, peer-reviewed sources in
this answer.
What you are referring to is cardiac rehabilitation.
A lack of physical activity is one of a variety of risk factors which
are thought to have adverse effects on the progression of coronary
artery disease. Accordingly, cardiac rehabilitation programs have
developed to provide exercise and counseling on risk factor
modification in the secondary prevention of ischemic heart disease.
These programs have become an intrinsic part of the comprehensive care
of these patients.
In a retrospective study over 12 years, physical activity habits were
analyzed in 10,269 Harvard alumni (1). Those men who engaged in
moderately vigorous sports activity had a 23 percent lower risk of
death than those who were less active. In a subgroup of 782 men with
documented coronary artery disease, those with physical activity
energy expenditures greater than or equal to 2000 kcal/week had a 29
percent lower death rate from coronary disease than subjects who were
less active. The improvement in survival with exercise was equivalent
and additive to other lifestyle measures such as cessation of smoking,
control of hypertension, and avoidance of obesity.
Results from randomized cardiac rehabilitation studies using only
exercise as the intervention have shown favorable but not significant
improvements in morbidity and mortality, possibly due to the small
sample sizes studied. In one study, for example 193 patients were
randomized after myocardial infarction (2). With an average follow up
period of about 4.5 years, the annual mortality rate for the exercise
group and usual care group was 3.6 and 5.8 percent, respectively. The
respective annual cardiac morbidity rates were 3.6 and 4.9 percent.
The National Exercise and Heart Disease Project is the largest
randomized trial conducted in the United States on the effects of
exercise on morbidity and mortality in patients after MI (3). This
study randomized 651 men, two to 36 months post myocardial infarction.
The intervention group underwent eight weeks of monitored exercise
followed by unmonitored but supervised sessions three times a week
thereafter. Subjects were followed for three years. The following
benefits were noted in the exercise group compared to the control
group:
· Total mortality was reduced — 4.6 versus 7.3 percent
· Cardiovascular mortality was reduced — 5.3 versus 7 percent
Although these differences were not statistically significant, the
investigators noted that, if the data trend had been observed in a
comparable study of 1400 patients, the benefits would have been
significant.
One randomized trial has shown significantly improved survival. In
this study, 301 men and 74 women were randomized to a
multidisciplinary cardiac rehabilitation program including exercise
training, behavior modification, nutritional, and psychological
counseling (4). The three year cumulative mortality rate in the
treatment group was 18.6 percent compared with 29.4 percent in the
control group. This difference was largely attributed to a reduction
in the incidence of sudden death in the intervention group (5.8
percent versus 14.4 percent). Nonfatal reinfarction was similar in
both groups.
In a ten-year follow up study, the same investigators reported a
persistent benefit of intervention in terms of sudden death (12.8
versus 23 percent) and coronary death (35.1 versus 47.1 percent) (6).
The difference was most marked in the first year after infarction, a
time at which the use of beta blockers was not different between the
two groups. Once again, the incidence of nonfatal reinfarction was
similar in both groups.
In summary, death from MI is reduced in physically fit men.
Multifactorial cardiac rehabilitation can produce significant
long-term reductions in both total and cardiovascular mortality.
Please use the answer clarification to ask any questions before rating
this answer. I will be happy to explain any issue.
Thanks,
Kevin, M.D.
Search strategy:
No internet search engine was used in this answer. All sources are
from objective, physician-written, peer-reviewed resources.
Additional links: (search strategy – “cardiac rehabilitation” using
Google)
John Hopkins Heart Health
http://www.jhbmc.jhu.edu/cardiology/rehab/patientinfo.html
American College of Cardiology Guidelines
http://www.acc.org/clinical/guidelines/nov96/edits/jac1716pvii.htm
Bibliography:
1)Paffenbarger, RS Jr, Hyde, RT, Wing, AL, et al. The association of
changes in physical-activity level and other lifestyle characteristics
with mortality among men. N Engl J Med 1993; 328:538.
2)Roman, O, Gutierrez, M, Luksic, I, et al. Cardiac rehabilitation
after acute myocardial infarction. 9 year controlled follow up study.
Cardiology 1983; 70:223.
3)Shaw, LW. Effects of a prescribed supervised exercise program on
mortality and cardiovascular morbidity in patients after a myocardial
infarction. The National Exercise and Heart Disease Project. Am J
Cardiol 1981; 48:39.
4)Kallio, V, Hamalainen, H, Hakkila, J, et al. Reduction in sudden
deaths by a multifactorial intervention programme after acute
myocardial infarction. Lancet 1979; 2:1091.
5)Hamalainen, H, Luurila, OJ, Kallio, V, et al. Long-term reduction in
sudden deaths after a multifactorial intervention programme in
patients with myocardial infarction: 10-year results of a controlled
investigation. Eur Heart J 1989; 10:55.
6)Herline-Iaffaldano et al. Efficacy of cardiac rehabilitation after
myocardial infarction. UptoDate 2002. |
