Help with Max HR test -- can't get HR very high

and I should add that all of these time trials were run in warm weather during the afternoon

Hey, since no one else is chiming in, here's my two cents.

That's not much of a difference. A lot of things go into determining that brief duration of MHR, and you can't get too precise about it. It's really a generality, and there is some degree of inaccuracy in the measuring of it.

I wouldn't give it a second thought.

For me, HR data is more like something i watch as a curiosity but i would never let it steer my training. When it makes sense, great, and when it doesn't, i just keep watching to see if something reveals itself.

HR is actually more important in gauging your training zones rather than at the fringes (like max. HR)

But again, a change of 10 bpm at the most is not too much, esp. when you are talking about a window you hit for a very brief time (most people can't hold MHR for very long - it isn't sustainable).

Situation normal. You measured your max HR first when you were untrained, so it was relatively easy for strenuous exertion to shoot you up to max HR. Now you're in much better shape, which means there are more limiting factors, not just your max HR. Your heart probably beats more efficiently now, distributes blood to your muscles more easily, and has a higher stroke volume. That means to hit max HR now, you have to be working really, really hard, and in most situations you'll fatigue before you get there.

So don't worry about it. Your goal is to get fitter and faster, not to hit a max HR. Use the number on your watch as one piece of feedback among many, not the one thing that controls your running.

In the same boat right now. It's just because you are fitter.

I could hit 186 bpm after a hard steep hill sprint (and have burning lungs, etc afterwards). A year later with a better base, I struggle to get it above 170 bpm on a series of hill sprints and recovery quickly.

thank you all. So if you're working out and aiming for say 85% of max HR on a light tempo... you use the old max hr even if that might not be your max today? I hear all the "just run by feel and don't worry about it too much" advice, but as I've run tempos and workouts too hard very frequently in the past, I fear I do need some kind of moderating limiter like HR feedback.

I would use the highest as your max, providing it has been reached within the last year or so.

1 mile TT on the flat is probably not the best for a max hr test. A few really hard reps up a short steep hill may be better.

For some people, a mile TT won't elicit Max HR. I would only come within several beats of my Max HR in a mile race.

That said, I don't think Max HR is a useful number. Even if you know it exactly, you're then forced to use a range of several beats for zones. This is particularly frustrating for tempos. In my case, the difference between the low and high end of the tempo zone would be a difference of a minute per mile in pace! Thus, you're forced to guess, as you did with 85%.

A better approach is the old Joel Friel Heart Rate method to find your LTHR (Lactate Threshold Heart Rate). LTHR is the HR where your energy systems begin to shift from aerobic to anaerobic.

The new method is to do a 30 minute time trial. I assume it's accurate, but I have no firsthand experience with it so I'll describe the old method. (You can look this up online.)

The old method was to run for 2 miles easy as a warmup... say 15 minutes or so. Then, without stopping, start your HRM and accelerate to the pace you would run in a one hour long race. Hold this pace for 30 minutes. Take splits at the 10, 20, and final 30 minute mark.

Disgard the average HR of the first 10 minutes of this final 30 minute run. Look at the average HR for the 20 and 30 minute marks. Is the 30 minute split HR average within a beat or so of the 20 minute split HR average? If so, that's your LTHR. If the 30 minute split is, say, 5 BPM faster, then you ran too fast and became anaerobic towards the end. You have to rest a few days and repeat the test.

Example: I did this test and my split HRs were 152, 160, and 162. Since the 2nd and 3rd split were within a couple of beats, I assumed my LTHR was 162 so 162 was my upper limit for tempo runs. I could hold pace at 162, but if I allowed my HR to creep up AND stay up a few beats higher, I would have to slow eventually.

At the time, my MHR was 190, as determined multiple times at the end of 5k races when finishing with a hard kick over the last quarter mile. (Also determined by a university treadmill test in a lab.) Using traditional methods of 80-90% being the lactate threshold, my zone would have been 152-171. That's so wide as to be nearly useless. It forces you to guess, as the OP did at 85%. In my case at my then level of fitness, 85% would have been right on the mark. BUT if I thought the range was 80-90%, I might have tried to push it to 90%, which would have been too fast for me.