Thursday, May 17, 2007

News from the Heart

Today I ran with something called a heart rate monitor. I actually used to use one of these back when I raced bicycles, though it was difficult back then trying to dodge all the dinosaurs walking about. I tossed it aside once I quit riding and moved into marathon training, though I did find one log entry from March of 2004 where I was training for the Vermont City Marathon and apparently wore the monitor for a bit. Back then I was crazy into Pete Pfitzinger's training, and with an average of 60 miles per week for 18 weeks I ran a 9 minute PR to go just under 2:48.

In training for that race I estimated my threshold heart rate as 175 after wearing a heart rate monitor for a 10 mile race where I ran my hardest for close to an hour. From there I figured I could run a marathon at 90% of that heart rate (I forget why, but Pfitzinger probably said it somewhere). I have some random notes that suggest an elite runner could run a marathon at 88-91% of his threshold and that a competitive runner could expect to run at 88-91%. This stuff gives me a headache now, but back then it suggested I could run a marathon at an average heart rate of 158 or so. I still have no idea what my heart rate was when I ran the 2:47, but during my training I have my first 7 miles of a marathon pace run at 6:15 pace with an average heart rate of 159.

Today Mystery Coach asked me to wear the heart rate monitor to run 7 miles at a 150-155 heart rate. He mentioned that the actual heart rate number is less important than getting specific data to compare it against later on, so I tried my best to be good and stick to the plan. After a one mile warm up to slowly build the heart rate up to the prescribed level I hit the lap button and tried to just run steady. Since I had the Garmin on my other arm I decided to ignore pace entirely and solely focus on keeping the heart rate within the 5 BPM window. This proved fairly easy for the first 2.5 miles, but once I turned onto my 1 mile loop I noticed immediately the drop in heart rate on one quarter mile section (where I invariably had to speed up a little) and a similar section on Sabino Canyon road where I had to noticably ease off on the speed to keep the monitor from going over 155. The one time I accidentally looked at my pace it was just at 4 miles, where I saw 6:11 as the average. For the last three miles it seemed I had to slow a little more on the slight uphills, though the effort still felt quite comfortable and easier than marathon pace. When I made what I knew was the last turn and clicked the watch again at 7 miles it showed an average of 6:15 for the duration. Apparently I had to slow down more than I thought, since this means I averaged 6:20 for the last three miles after averaging 6:11 for the first four. While there was a net downhill for the first portion, it still doesn't completely address the drop in speed over the second half. Luckily I have Mystery Coach to help dissect the data, as I'm at a bit of a loss for interpreting it myself.

Yesterday was an easy 9 miles in the morning, followed by another 6 easy miles in the evening. Again, I'm making a real effort to run the easy days a bit easier than usual this week in order to stay fresh for the 5K on Sunday.

Training: Today, 8.25 milds, 52:30, 6:21 pace, w/7 miles at 6:15 pace and 150-155HR
Yesterday a.m., 8 miles, 56:00, 7 minute pace. Felt nice and easy
Yesterday p.m., 6.2 miles around 6:50 pace

4 comments:

Andrew said...

I'm glad to see you own an HR monitor.

A very good pace. Your net downhill (relative to the 2nd half) would make a difference coupled with the "drift" of increasing mileage. I'd suspect the average pace would still increase a tiny bit more over the next 7 miles.

I'd prescribe 90 minutes at this pace every other day as your "easy".

What baseline (if that's what it was) was Mystery coach looking for?

Dusty said...

Heart rate monitors give me a headache too. My sports med doc wanted me to run with one and told me what my threshold should be - I was over it on an easy jog. I need to follow Phil's advise and use it on some hills, but will have to wait a few weeks. Keep posting on this, I like the idea of not worrying about the numbers, but how they play against each others - less likely to freak me out. Interested in hearing more.

Mike said...

Andrew, the one I own is actually dead from lack of use so I'm giving it to my friends at the Running Shop to send back to Polar for batteries. Luckily they had a loaner I could borrow. I'm guessing the coach will get back to me soon with a baseline, but for certain it will be a moving target. I anticipate the first few weeks of higher miles alone will increase the aerobic capacity after so many lower mileage racing/racing prep weeks and the average paces will improve.

Dusty, I don't think I could run with a monitor every day, but once a week or so probably wouldn't kill me. I trust the coach though, so even if he told me to wear bunny ears on every run I'd probably listen.

Marc said...

Mike - I too am new to the HR monitor scene. Like anything, I think it needs to be used as an assessment tool and guide rather than commander-in-chief.

I think the bunny ears work best when worn with a tutu.