Exercise After Heart Attack

QUESTION: After recovering nicely from a heart attack, my physician suggested
that a carefully structured exercise program could lead to new arteries
growing in my heart that would protect me from future attacks. I am now
jogging, though at times it's a struggle, and I keep wondering if this is
really working. What do you think?
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ANSWER: Your question leads us into some interesting medical history, and a
current area of debate. Anatomically speaking, there are two types of
arteries; those that end at the tissue they feed, appropriately named "end
arteries," and secondary or branching arteries that connect main artery
systems, called "collateral arteries". When an end artery becomes blocked, as
during a heart attack, the tissue it serves dies, unless blood can flow to the
tissue through collateral vessels. An early English physiologist, Richard
Lower, described the presence of collateral vessels in the human heart in
1669, and this was accepted doctrine until 1873, when Josef Hyrtl, professor
of anatomy at Vienna, failed to find these arteries using a technique that
made a cast of all the vessels and corroded away all other tissue. These two
opposing views were debated for 80 years until 1960 when W.F. Fulton showed
that tiny capillary-like channels did indeed connect different coronary
arteries. It is pretty well agreed that reduced blood flow to the tissue of
the heart stimulate these capillaries to grow and increase blood flow to the
suffering tissue. It would certainly appear to be so in important experiments
conducted in animals, and we know that patients that have survived longest
with chronic coronary artery disease (CAD) show increased collateral
circulation when post mortem examinations are performed. Your physician is
correct in that patients with CAD do better when following a prescribed
exercise training program. What is missing is the proof that the increased
demand for oxygen needed by the heart during exercise can be the stimulus for
new growth in the collateral vessels in humans. Investigations that might
prove this are difficult to construct and costly to run. Until such data is
available it is difficult to answer your question absolutely, but in my
opinion from existing research, you are probably doing yourself a world of
good.