A.M. Ran with Jeff, Daniel, and Tyler Cannon. Jeff and I thought we felt good enough for a tempo run. So we attempted one after a warm up. First mile was supposed to be a good rhythm mile, then 5:20, then fast. From the get go it felt hard. The first mile was 5:46 and I felt like I did not want to go any faster. Then we sped up reluctantly to an 81 quarter, followed by 78, then I backed off and let Jeff go, 80, 81 for a 5:20 mile. HR was 162-163 at 5:20 pace, but I felt like I could not push it any higher or go any faster. Assumed adrenal failure, decided it would be counterproductive to try to run through it in training since I already do that in races. So at that point I eased off. Jeff ran 5:19 - 5:08 for the last two miles. At 5:04 pace Jeff's HR was 184. Then we jogged back. Did a fat mile in 5:58. Measured the respiratory rate of 17 breaths per 100 meters.
Then I proposed that perhaps there is a pattern (for me) of 15 breaths per 100 meters on a good day, and 17 on a bad day. Jeff suggested that there is too much room for error in this test. I wanted to know how much, so we decided to run half a mile at around 6:00 pace counting breaths in the second quarter with the goal of breathing as little as possible. Our half mile time was 3:01 with the last quarter in 1:29. Jeff took 20 breaths over the last quarter. I took 49. 10 in the first 100 meters. It was really odd to breathe this way, and I think eventually I would have had to revert to the natural breathing pattern if we were to continue.
From that I developed a working theory. There is a certain optimal air volume per breath, and it is fairly consistent on any given day. It is possible to breathe in more than that, but the faster the pace, and the longer you go at it the harder it is to do it. That optimal air volume, however, on a good day will be higher than on a bad day. It is not related to the heart performance. In fact, for the same runner, it is possible to have a lower HR at the same pace with that optimal volume reduced at the same time, so he is breathing harder even though HR is lower! Another illustration of how unrelated this is to HR is comparing me and Jeff - Jeff's optimal respiratory rate at 6:00 pace is 13 breaths per 100 meters. Mine on a good day is 15, and 17 on a bad day. Good day and bad day HR for me would be about the same. Yet his HR at any pace is 15 bpm higher than mine.
So in short, for me: good day - can sustain HR at 165, natural respiratory rate 15 times for 100 meters at 6:00 pace; bad day - HR cannot be sustained above 162 for signficant periods of time, natural respiratory rate 17 times per 100 meters at 6:00 pace. The HR has been tested for a while already, so I am quite sure about that. Respiratory rate needs more testing. But what I like about it is that if it proves reliable, 0.5 miles of 6:00 pace could tell me what's up, and that is a very non-invasive test.
P.M. Decided to try the new shoe. Well, I had that shoe ever since I was born, but had not used it much. It is completely free and available to all, and is called Bare Feet. Sarah said being a city boy I would not be able to handle it on asphalt. I ran 2 miles with Jenny in 18:44 (Julia ran the last 1.5 in 14:10), and 2 more with Benjamin in 16:29. It hurt a little bit, but once the run was over, the only negative result was minor blisters on the tips of the big toes. Noticed that even compared to Five Fingers, Bare Feet form was different, noticed my right hip flexor working harder. Will probably need another 3 months before I can do all of my easy miles barefoot.