heart rate/tempo run

I think many would agree that the purpose of a tempo run is to run at or near the lactate threshold. At the threshold pace and faster, lactate will rise steadily and you will fatigue quicker. If you run slower than the threshold pace lactate will stabilize at constant levels depending on speed, and you can run for up to an hour before the heavy fatigue kicks in.

The corresponding heart rates for this threshold can be between 80% and 97%. The effect is not the same across the whole range. The effect is similar under the precise threshold, and the effect is similar above the precise threshold.

To find this threshold, you need to either draw blood lactate (expensive and time consuming), perform the Conconi test (not accurate), or go on trial and error of feel.

I personally have found that under ideal weather conditions, 180-185 HR is the proper range for me. It feels like riding a bike. But at 190, I feel like I'm straining. The threshold is likely at 185 or so.

But really the HR monitor isn't going to work unless it's 70 degrees or cooler with low humidity and light wind. So learn to feel the point I described above and you'll be golden without the HR monitor.

Thanks for the information Joel. It was helpful.

Let me prfeace my remarks by saying that I am no where near the ability that a lot of people on this board are at.

I have had a lot of luck running my tempo's in the 85-90%MHR range. Durring this marathon cycle, I was able to increase my pace on these runs from 6:35-ish to 6:10-ish, while staying in the same range, and also increaseing the legnth of the runs (starting at 20 min. @ pace, ending @ 50 min. @ pace). I tend to stay on the very lower end of that range. I have heard from many people, including some sub-elite guys, that they believe that right around 88% MHR seems to be the magic spot. Based on my personal experiences, I would say that's true for me too.

Thanks Doug

Fitter athletes run at higher heart rates before lactate shoots up. Out of shape people may run at 80%. In really good shape above 90% is possible. Some athletes have run in the higher 90s, as incredible as that sounds. I know of at least two of the top of my head: Pat Porter (according to Joe Vigil he ran up to 96% when in peak form) and Bill Koch, famous xc skier medalist in the winter olympics who said that he could hold an effort at 5 beats below maximum for an entire 30k ski race which is about 85 minutes and 10 beats below maximum for a 50k race when in top shape.

Testing runners at the Univ. of WI lab, I would say that most collegiate runners hold between 86 and 92% of their maximum at threshold, say 89% as an average of the good ones.

During my tempo days (off and on over the past year) I would run a 10 miler at a solid aerobic pace. (That's not very precise, I know.) But, I would start well below my goal HRR (90%) and find a pace that felt good. If I hadn't reached my 90% by 10k, I would speed up a little. I found that the first few miles went pretty easily and the lactate accumulation didn't really occur until about 7-8 miles at those HR's. I've read elsewhere that cruise intervals (1-2k) can be closer to the 92% HR zone and still be equally effective. There's a function relating intensity to time though I don't know what it is. 92% can be 10k race pace for anything over a few miles. But, if you do short reps at that pace, your HR will not peak out too much. However, if you run 88% HRR, then, you can put in a full hour or so without much problem. Finding the middle ground between these two extremes will probably help clarify this.