Sunday, August 01, 2010

Depressing Blood Pressure and Mood

I did a longish run for the first time in a while and thought ahead, or was possibly procrastinating and took a before-run blood pressure and pulse.

127/78 pulse 63 before. Ran 13.1 miles in modest heat.

112/68 pulse 63 after. I drank about 20 oz of fluid after running and took a shower before taking the after run reading, so this was maybe 30-40 minutes post-run. There are different theories as to the cause of decreased BP after an endurance event. Dehydration: After all, some of the more common BP meds are diuretics, so this makes sense. Though I had replaced most of the lost fluid before taking the post run reading. I think distension of the veins and arteries makes a lot of sense too; they get stretched-out from being under pressure for a while and it takes some time for them to recover their former state.

The time on the run was a big disappointment though; I was on track (roughly) for the first 8 miles and then just felt like there was no energy left and my time reflects this.

Later, I got the idea of giving one of the girl's a math problem related to my recorded pulse rate. 63/minute translates into how many seconds per heart-beat? Naturally it took the girl about five minutes to solve what should have taken ten seconds; and I did require it be solved in the head (no paper, no calculator.)

Answer: 19/20 sec per beat or 0.95 seconds per beat in decimal form. The way I did it is to reason that 60 BPM reflects one beat per second and there are three more beats/minute to account for. This is one beat per 20 seconds extra, which is to say that if we take-off 1/20th second from each beat, then we can fit the remaining three in to one minute. It doesn't come out exactly to this amount though since we have freed-up three whole seconds for the three remaining beats, but assuming they are the same length as the other 60, they are slightly shorter than one second each. This estimated answer is therefore off by one 420th of a second.