Fast Twitch/Long Run

I use a heart rate monitor several days a week.

Why? Because it helps slow me down and stay in the proper training effort. For every run, I try to think "what is the purpose of this run?" Using the HRM I can then execute a run that corresponds to that purpose.

Purpose: Recovery/easy mileage/long run
HR zone: 70 to 75 percent.
I have an observed HR Max of 193. Seventy-five percent is about 145. I try to stay under this number at all times on easy and long runs.

Purpose: Lactate threshold development
HR zone: 80-90 percent for 45 to 75 minutes, can take 60-90 second jog breaks if building length or upping intensity. i find it helpful to ivbe myself a 5 beats-per-minute "zone" and to work my way up into the zone over the first mile or two, then to stay in the lower end of the zone early and use the top of the zone as the warning sign to back off. As a fast-twitch runner, I have never been able to really nail the idea of having a rock-steady heart-rate at a certain pace, so a 5 BPM zone is as good as it gets for me.

Purpose: Speedwork/Vo2Max development
HR Zone: Mostly irrelevant. The HRM cannot guide this kind of workout as repetitions are too short and intense. by the time your HR is really moving, it will likely be time to stop. And since you are exceeding your lactate threshold, by a little or a lot, your heart will have to work hearder to keep up. That's OK. Base work developes the capallaries and mitochondria in the muscles to use the oxygenand fuel; speedwork developes the heart/lung ability to deliver that oxygen and fuel. Now I did say mostly irrelevvant. It can be helpful to wear the HRM in these workouts just to observe what is happening, especially on the recovery jogs. When fit, your HR should get back down to 70-75 percent during an easy jog interval. If it doesn't, the session may be too intense and perhaps should be abandoned.

Abandon a workout? Yes, as master's runners, we must always err on the side of caution. Injuries and burnout are much more common in our age group from the same training that you used to breeze through as a 20-year-old. Do not be afraid to skip a workout or end it early. Often, this is the wisest course. patience and persistence is what training as an old guy is all about.

A couple of other notes:
- Do not trust tables that say your HR Max is 220-minus your age. This is wildly inaccurate. Find your own max, either the highest number you hit near the end of a 5K, or do a good long warm up then hit some long hills as hard as possible. Or do a couple of all out 800s with a short break. Somewhere in there you ought to hit a number within inches of your HR max.
- The HRM is not fool-prrof. On very hot days, your HR can soar. It's OK to exceed your easy run max by a little, but also note that the heat is adding stress and don't go nuts. The HR can also be artificially low on days when you have not refueled well from your last workout. THis is a warning: If you are running at your easy pace, but if feels sluggish and hard and your HR is low, you need to eat more. I think I'll post up a bit about diet later.
- The ultimate goal is to get a runner to understand how to run by feel. Eventually the HRM won't be necessary on easy days. You'll know that feeling of going for a good steady eight miles and coming back refreshed instead of run-down. Top runners will learn what other various levels of effort ought to feel like, and when very fit some can predict with great certainty what their heart-rate actually is in the middle of a run.