I've been reading that developing one's aerobic base is good for improving overall speed, and that to do so, I should be training at 60-75% of MHR. Is there still merit for overall speed in training above 75% of MHR? Or should I be saving that for trying to set a new PB once a month of something?

Background: I'm getting back in to running, I've read that one of the tests used when joining the UK military is to run 1.5 miles in <12:30, and then another 1.5 miles in <10:00. I don't particularly want to join the military, but it seemed like a good target - 3 miles in under 22:30. I'd also quite like to beat my half-marathon PB.

  • This is entirely speculative, but if you're running at such a high MHR that you can not sustain it for long enough, your progress should be more towards completing short runs in short time than long runs in short time.
    – Mårten
    Commented Feb 17, 2015 at 14:35
  • How did you determine your MHR? And if you say anything other than a ECG monitored clinical stress test, your MHR is at best a guess.
    – JohnP
    Commented Feb 17, 2015 at 15:04
  • @JohnP I'm just using the 220-age to get 195, I realise this is just a guess, but figured it would be a good enough approximation.
    – Joe
    Commented Feb 17, 2015 at 15:41
  • @Mårten I can sustain running at > 75% of MHR, I just want to find out what kind of training will yield the best results.
    – Joe
    Commented Feb 17, 2015 at 15:41
  • 2
    @Joe - 220-age is one of the worst myths in exercise science. Do one of the field stress tests that you can monitor either yourself or with a friend and a stopwatch. You'll get much better results, especially if you repeat at 3 or 6 month intervals.
    – JohnP
    Commented Feb 17, 2015 at 15:56

1 Answer 1


You get better because you put training stress on your system - that is what causes the adaptation. Initially, pretty much everything you do causes training stress, so you get better, but if you keep running at the same intensity, you will plateau. Which may be fine if that's where you want to be.

If you want to continue to improve, however, you need what is known as specificity, which involves workouts that are shorter but targeted at improving specific things. So, when you reach a certain point, not only does high intensity work benefit your overall speed, it's really the only way to keep improving.

There are numerous different approaches to doing this, from structured programs like specific intervals to informal ones like fartlek. I suggest finding a good running forum and asking there.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.