Is It Time To Get Started On Those Collateral Vessels?

Everyone knows that the heart is a muscle. But who wants to dwell on it? I am well aware that my heart --progenitor and keeper of my desires, pangs and longings ---has a mechanical side, but I like to keep that awareness at a comfortable distance. The ceaseless pumping action over which I have no control, as if this heart had been placed within me by aliens, or mad scientists, freaks me out a little. To contemplate my heartbeat is to imagine it stopping, which brings into focus my mortality, which is best relegated to a fuzzy blur in the background.

Yet this organ's staggering workload cannot be denied. The wattage it puts out over a lifetime could light up Manhattan. Okay, not exactly. But it could power 2000 one-ton trucks speeding past at 160 miles per hour. The heart's normal 1 to 5 wattage, sustained for say, eighty years, adds up to two and a half gigajoules. Which sounds like a Cajun stew, but is actually a tremendous amount of energy. A gigajoule is equal to one billion joules, which is equal to the energy expended (or work done) in applying a force of one newton through a distance of one metre (1 newton metre or N·m), or in passing an electric current of one ampere through a resistance of one ohm for one second. The joule is named after English physicist James Prescot Joule and is measured in SI units.

My personal goal for heart wattage is to shoot well past the two and a half gigajoule mark, aiming for say, two and three-quarters gigajoules. However, there are certain hard-as-plaque realities one must face: I like fat, and lots of it. In some quarters I am known as the Dairy Queen, wantonly consuming milk products with high levels of saturated fats --the baddies. My favorite foods are cheese, ice cream and fried potatoes, or potatoes with butter and/or cheese. I like old World cheddars, and creamy Pont L'eveque. I like Ben and Jerry's. Where can all of this lead? Can I allow myself to believe that my arteries will maintain an adequate bandwidth on such a diet?

It was this nagging concern that drew my glance towards a recent article in the Mayo Clinic Health Letter. I work in a health science library, and medical journals cross my desk every day, but this article stood out because it suggested I can create my own work-around for my potentially beleaguered arteries.

Using bold graphics, the article showed two meaty bundles of contractile tissue in vivid detail. But one of those hearts was not like the other. One had a burgeoning network of little blood vessels branching out from its main artery, while the other heart had none.

Reading further, I learned that regular exercise creates an increased demand in blood supply, which stimulates the growth of new! collateral blood vessels. These collateral blood vessels are like evacuation routes, for when your blood is trying to get out of town and the main highway is clogged. They provide a detour around the point of congestion back to the main road. We all want ancillary roads to open up for us when we encounter a traffic jam, as in the Simpsons episode, where Homer's membership in the exclusive Stonecutters club gave him access to a secret bypass that circumvented a car pile-up and got him to work in record time. Well, imagine if you could build such a road within your heart for a day when you might need to fast-track your blood flow downstream? You could be headed towards a calamitous heart event, as your plaquey pipes begin to close, yet have only a whisper of an attack, thanks to those collateral blood vessels.

This information puts cardio fitness into a whole new light. Working out to make the heart more efficient has always seemed a little too abstract for me, but exercising to create new highways and byways is exciting. These extra blood vessels will enhance my body's overall circulation too, turning my winter pallor into a deep, ruddy glow. And as if that weren't enough, exercise improves the function of the endothelium, the thin layer of cells on the inner lining of the vessel that causes the vessels to contract or relax. Quite a payoff.

So how much exercise is enough? The Mayo Clinic Health Letter says 150 minutes a week of moderately intense activity is better than nothing, moderate being where you can talk but can't sing. But the most benefit comes from six to seven hours a week. Holy deep-fried cannoli, that's 60 minutes a day. That will definitely cut into my fondue hour.

I'm going to have to give this some serious thought.