I finally got motivated this morning to get back out on the bike after a seven week hiatus. Throughout the whole ride the only thought that kept going through my head repeatedly was “70 miles!?! – 70 Miles ?!? – 70 miles!?! – seriously?!” This recurring thought was not caused by the fact that I was actually riding 70 miles – I was only out for 40. Rather it floated through my brain with every pedal stroke simply because whenever one of my feet would reach the rotational apex of of the crank arm, my thigh would slam into my belly, a condition to which I am not very accustomed. Yep, that’s right: as of yesterday, I have officially gained ten pounds since completing our last race back in mid-August. Not nearly as bad as a year ago (this time last year I had actually put on twenty) – but bad enough to motivate me to get out on 32 degree day for a ride.

So why “70 miles?” Well it seems that I remember reading some years ago in Runner’s World that one pound of fat contains approximately 7 miles of arterial capillaries. So ten pounds of fat  means that the ticker has 70 extra miles through which to push blood on its round trip circuit. As you might imagine this this can create a dramatic increase in head pressure on the ol’ cardiovascular system, which really showed on the road today. OK, so “70 miles” does make for a dramatic and motivational image and all, but is it really true? well, a quick Google search turns up this bit of scientific blargity-blargity, in which Dr. Ed Friedlander, M.D. and Pathologist states:

“How many miles of blood vessels are there in a pound of fat?” People write me about this every once in a while. Let’s figure it out. Assume an adipocyte is 50 microns across; it’ll vary from 10-100 depending on how fat the person is. The fatter you are, the less vascular is your fat, which is one more reason that this whole inquiry is silly. In a section of body fat, which I examine often enough under the microscope, the capillary (there has to be at least one) that supplies each fat cell is not usually visible, so I’ll assume one per adipocyte, and all going in the same direction. Put a single capillary between each pair of fat cells and that’s about 20 capillaries per millimeter, or about 500 capillaries per inch, or 250,000 capillaries per square inch. Assume a pound of fat is a cube 4″ on a side, which is good enough for junk science, or 16 square inches, and that is 4,000,000 capillaries running through the cube, 16,000,000 inches. There are 12 inches in a foot and 5280 feet in a mile, so if you get 500 miles you did the arithmetic the same way that I did. If you prefer 100 miles as in other estimates, simply assume that there’s a capillary between every other pair of adipocytes, rather than every pair. That this question is fundamentally wrong-headed can be understood by anyone who considers whether moving a certain total number of cars through Kansas City would be easier with more highways or fewer highways. Further, the vast majority of these capillaries are completely closed at any moment during your life, and not carrying any blood. At autopsy, blood usually dribbles from other organs but not from fat. At surgery, other organs bleed plenty but fat barely bleeds. The real question isn’t, “How many extra miles of blood vessels?”, but “How much rougher is it on my heart to be fat?” Think about walking around carrying 100 lb of weights everywhere you go.

Well just blah. I still prefer to think that it is the 70 miles of blood vessels that are slowing me down, rather than a dramatic loss of fitness. I mean that is something that a little liposuction can take care of. If it is indeed the fitness, it seems that I am actually going to have to get back on a regular training regimen again. Rats.