Max HR when trying Interval Training

100% of what?? How have you determined "max", or "threshold"? If it's just something your monitor (or you) sets on the basis of your age, etc., it may not be appropriate for you. if you are an experienced and healthy enough runner to safely do a 20-minute "test", you can determine your threshold pace with a 20-minute max effort (or you can get the data from a 5K if your 5K time would be in the 20-25 minute range). You can then figure the paces, or % of threshold heart rate, from that.

For example, my average HR from that test was 176. I haven't been doing any really fast, short intervals lately as I'm training for a half-ironman, but it would be pretty common for my HR to be well into the 160's (which would be 90-95%) on some harder tempo-type efforts. That's hard, but not ridiculously so.

My max HR is pretty spot on. I was doing it based on age and that formula. I was putting all I had and it was at 100 percent.

So just slow down a bit! Most intervals that people would do in training for the run distances in a typical triathlon (5K to marathon) should not be "all out". You will build fitness better by doing mostly easy runs and, if you're an experienced runner, a small amount of running at or slightly below race pace. "Max effort" carries a much greater risk of injury and in general isn't worth the risk unless it's a race and there's a finish line in sight, or you're being chased by a buffalo or something.

No need to look at your watch every single second. It depends on the length of the interval, but normally I look every 20-30 seconds. Also realize that it takes your heart rate a while to climb in response to increased effort, so it won't hit the target heart rate in the first few seconds or even (for less intense work such as tempo runs), for a minute or more. It will also rise faster in the heat, which means, depending on your training goals and heat acclimation, that you either slow down a bit in the heat (if your race is in the heat, and you're still acclimatizing), or accept a slightly higher target heart rate range for some workouts (if, as I sometimes do, you're training in a hot climate where you're well acclimatized, for a race that's in cooler conditions).

After a while you will get used to the effort level required to hit different target heart rates, and you won't need to look at the watch so often.

Edited by Hot Runner 2016-04-22 8:08 AM

Those two sentences don't really go together. "That formula" (and there are a few different variations) can be accurate for some people, but pretty far off for others. Not everyone who is the same age has the same Max HR. There are test protocols for determining your Max HR, and none that I've seen involve 600m intervals.