Saturday, September 30, 2006

18 Miles with a Heart Rate Monitor

Starting to add to the gadgets once again. I got a heart rate monitor--albeit the simplist one that I could find, a Polar B1. Don't bother looking for it at the "official" site, it is too basic to make the list. I got it at a good price, $30, through In Dave McGovern's clinic we did some heart rate monitor training and it was quite interesting. According to the test we did in class, my maximum heart rate is about 191 beats per minute (bpm) which is pretty good because if I would have used the rule of thumb method (220 - Age = Maximum Heart Rate) I'm 29 years old! (Actually, I'm 51.) Another measure is lactate threshold, which is the point at which the body can clear the lactate acid from the muscles, and that came out to about 172 bpm. A general endurance walk like today should be done at around 65 to 75% of maximum heart rate, about 124-143 bpm. But that's not how it went.

The easy first mile started out at 145 bpm and most of the walk was around 155 bpm. Towards the end it got warmer, I was getting tired and I was pushing harder on the last few miles, it was up to about 165 bpm. Anyway, this is the first time using a heart rate monitor so I don't have enough experience to know how much my heart rate fluctuates during these training walks.

I started the walk at the Santa Monica Beach pier at 8am and headed past the Venice Beach pier, 6 miles round trip for three laps. By the time it was over I had dodged three bicycles, slowed down for a downed Rollerblader, stopped to kiss my wife twice (who was doing a much shorter walk with our dog) and weaved my way through countless pedestrians. Still, I managed to get close to my 13 min/mile goal pace for this walk--my marathon goal is 12 min/mile. Here are the numbers:
Mile  1 - 12:21            Mile  7 - 12:46          Mile 13 - 12:09
Mile 2 - 13:39 Mile 8 - 13:34 Mile 14 - 13:06
Mile 3 - 13:11 Mile 9 - 13:14 Mile 15 - 12:49
Mile 4 - 13:11 Mile 10 - 13:35 Mile 16 - 13:02
Mile 5 - 13:10 Mile 11 - 13:05 Mile 17 - 13:24
Mile 6 - 12:00 Mile 12 - 12:11 Mile 18 - 12:13

Total Time - 03:52:40
Average Pace - 12:55 minutes/mile

Great, I was able to beat the 13 min/mile goal even though I did start out too fast--as usual. Now how about crunching some of these numbers. First of all, did I have a negative split? This means that the second half was done faster than the first half.

First Half - 1:57:06
Second Half - 2:08:48

Even though it fealt like I was giving it much more effort on the second half, I didn't make a negative split. In fact the second half was almost 11 minutes longer. That could be attributed to getting tired, the temperature got hotter and the crowds that kept growing later in the day, especially in Venice Beach.

Now how about some other split times?

Approximate 10K Split - 1:17:32
Approximate 20K Split - 2:35:57
Approximate 1/2 Marathon time - 2:49:00
Approximate 30K Split - 3:52:40

These are some of the splits that are listed in the L.A. Marathon results for 2006. If this were the actual marathon I would be somewhere in the middle of the racewalk division. Of course there is still a long way to go after mile 18. In addition, if this were a real marathon I might have tried to do 12 instead of 13 min/miles and right now I'd probably hit the wall well before crossing the finish line.

There is still five months before the L.A. Marathon. I often wonder if I will I make it to 12 minute/miles by then?