5k Heart Rate Training and Heart Rate Zones Whilst Racing

First things first. You’ve obviously got a heart rate monitor! You realise that your heart rate can vary day by day for lots of reasons, such as illness or fatigue, and that this makes HR based training less accurate.

Oh yes and you will also find differences between the zones for different sports that you perform – depending on the muscle groups involved and the degree of external support (bike/water).


Use this spreadsheet HR Zone calculator (links to another page that explains the spreadsheet).


But neither of us are elite athletes so it won’t matter that much in reality!

NOTE, IMPORTANT: Before we get started you might instead want to look at this training program for 5k based on HR. In that post I show how to get zones based on LTHR (ATHR, OBLA) – which is the preferred method that I actually use – rather than the one below. I’ll say again, base your HR training on LTHR! <*THIS*> One tells you the same thing very simply. Oh well, instead read on!

Right, let’s get started, so we need your MAX heart rate and your MIN heart rate (or resting heart rate). HRmax and HRmin.

HRmax is a tad over what you last did right at the end of the sprint for your fastest 5k PB in the last couple of years. It is almost certainly Not 220-Age. (I repeat NOT 220-age). There are tests you can follow to determine. with some accuracy, your HRmax but we both know the reality is that you won’t do them!

Alternatively, look in your stats for your highest EVER heart rate – that’s the one. It could be cycling or running or whatever – sport is irrelevant. It’s the FASTEST *YOUR* heart can possibly beat at. Hopefully that’s clear by now! You measure OR record it…you do NOT estimate it with a formula.

HRmin is your lowest heart rate after resting for 20 minutes. Get it as low as you can. BTW This is a better measure of how fit you are rather than how high your heart can go. BTW2 My HRmin was higher when I wore my heart rate strap and watch all night (whilst asleep) than when I wore it resting for 20 minutes resting. Bizarre but true (for me) so maybe don’t waste your time trying that one (wearing it all night)!

Bioforce HRV - Sample Android Screen
Or HR Training Could involve basing what you do on HR Variability with Bioforce HRV

Let’s work out TRAINING zones using HRmax=200 and HRmin=50. Nicer round numbers.

Using this example – the 90% level (ie use 0.90) is: 0.90 x (HRmax – HRmin) + HRmin ie 0.9 x (200-50)+50 = 185 bpm

Do the same calc for the 80%, 70% and 60% levels. Do 85% as well (I’ll come back to why later). Do it with your own figures for you

Your training zones are broadly between these levels, so:

  • 70%-80% = Aerobic Zone
  • 80%-90% = Anaerobic Zone
  • 90%-100% = Redline Zone. Performance starts to degrade and continues to exhaustion.

You‘ll probably find that you run your 5k races in the anaerobic zone going into the redline zone for not very long towards the end. You would not be able to run 5k in the redline zone (if you can you are really good!). In the aerobic zone you are not trying hard enough for the race! Although the aerobic zone has its uses in training.

For example. In my last 5k PB here were my average HRs over each KM (note the 6th KM is for over running by me or under-measuring the course by them). My pace was fairly even throughout. For the purposes of our HR discussion that does not matter:

  • KM1 156 bpm (81% of max heart rate)
  • KM2 170 bpm (88% of HRmax)
  • KM3 177 bpm (92% of HRmax)
  • KM4 181 bpm (94%)
  • KM5 186 bpm (96%)
  • KM6 191 bpm (99%) 50m extra.

That’s a fairly typical race profile for me.  HR rises quickly for 0.5-1.0 km before plateauing and then slightly rising as fatigue sets in. I’m not unusual.

OK here’s where it gets vaguely interesting…

So, from the figures above, Race Average = 174 bpm (90%). This is slap bang in the middle of my anaerobic TRAINING zone.

You will probably also read of other types of HR zones. These are probably better than the basic one given above. But they often yield fairly similar results. Joe Friel and others will show better ones but often the tests you have to do for the inputs are not so straightforward as those above. As I said earlier, neither of us are elite athletes! The zones are to a degree arbitrary BUT what we will soon come onto is your lactate threshold level and this is VERY REAL.

So let’s come back to my 174 bpm average for the 5km PB. Well my 10k PB yielded an average of 172 bpm. I don’t really do 10ks that much and so again could have gone a bit faster and so would have my heart. My 1 hour bike TT has an average BPM of 172. So as you can see there is a degree of ‘coincidence’ here!!

So this 172/174 bpm (the 85% training zone/level you calculated earlier) type area represents the area somewhere pretty close to my lactate threshold (LTHR). My lactate threshold (LTHR) is probably I reckon about 175-9 bpm but I can’t quite push myself enough psychologically to find that out in training. 172 is hard for me to maintain but I can do it for an hour or so. I can do heartrates of the low 180s for a few KMs. [Your lactic acid threshold level is where your legs start to get progressively heavier and progressively ‘stop’ working; it’s caused by H+ ions a.k.a. a build up of lactic acid from going to fast…ie your body couldn’t get rid of it quick enough…sort of].

So what we want to do with HR training (well one of the things anyway) is to train upwards your lactate threshold ‘level’ (LTHR) and all the associated bits of that bodily system that you don’t need to understand. You do this mostly by training at just under that level. So I would train from 163-168 and up, something like that. This training makes my body’s systems change over time and the lactate threshold level moves further away in the right direction ie towards a higher heart rate and I can then train AND RACE harder. Well so the theory goes! Seems to work tho.

This does not necessarily mean that your max or min will change – they might. Just the threshold (LTHR) is what you are trying to change. That is the KEY thing to train to try to change. So if it’s the KEY thing, then base your zones on it (like I said at the start).

You HRmax, perversely, may FALL as you get fitter. This might be because of increased structural efficiency within the heart. (Source: A chat I had with the UK’s top cardiologist 🙂 )

You would probably also find benefit in under-over sessions (ie under and over your LTHR) where your intervals go above and below the threshold. To do that you CLEARLY need to know your LTHR (get it lab tested if you want, c£100).

Stuff to buy: The BSX Insight (review here) product estimates cycling/running accurately enough for a retail user.

You will also use your HR monitor to do other types of training (to train other bodily systems) . Your general aerobic fitness will come from long slogs of mileage in your aerobic zones. Other training will look at trying to increase your VO2max by fast sessions –  you might do REDLINE Sprints. Personally, for 5k I wouldn’t bother too much about anything below your aerobic zone if you think you are half competent at 5ks and building up to a PB attempt or race. Certainly my run training has me ALWAYS aiming for at least 160 and then running intervals where my HR goes into the high 170s and sometimes 180s. Then again my training time available each week is limited and I do other sports as well.

Then again I have not done primary medical research into this area. People who would argue with me will merely be reciting someone else’s science and not their own. Anyway it’s ‘right enough’ for us to get those 5k PBs down! Certainly over a 3 month period with limited time I would focus quite heavily on LTHR and VO2max training. Perhaps do a long run every 10-14 days. (*If* you are undertrained aerobically then you will benefit from long slow mileage).

Look at it another way if you do a 5k and your HRavg (average) is above the threshold then either you really were trying really, really hard – or your calcs were a bit out! (Probably the latter) So try harder still next time.

SO: HR based training obviously works. Some argue that there are better alternative approaches. Do I use HR based training? Yes for long sessions and longer intervals (over 20 minutes).

I also look at my recovery levels using my HRrest (waking, supine HR) and my HRV (Heart Rate Variability) – if you plan on doing lots of high intensity work you might want to look at that too.

Reader-Powered Content

This content is not sponsored. It’s mostly me behind the labour of love which is this site and I appreciate everyone who follows, subscribes or Buys Me A Coffee ❤️ Alternatively please buy the reviewed product from my partners. Thank you! FTC: Affiliate Disclosure: Links pay commission. As an Amazon Associate, I earn from qualifying purchases.

2 thoughts on “5k Heart Rate Training and Heart Rate Zones Whilst Racing

  1. This is the best stuff I have read for establishing HR ZONES- however your math example has the wrong MIN HR as 90 in your formula instead of the 50 you used. The answer of 185 is correct with the correct numbers. This has helped me establish my zones! Thank you!

Comments are closed.