5k: Simple HR Heart Rate Based | Sub 20 | minute running and training plan

Here is a simple plan to follow to run a sub-20 5k based solely on HR training Zones.

Maybe you haven’t got a pace/GPS feature on your training watch – that’s true for a lot of people.

I would recommend running faster training sessions based on PACE/SPEED, so you might instead consider <this 5k training plan>. Or if you fancy JUST using pace, then look at <this plan based on VDOT>.

Oh well, each to their own; let’s continue then based just on HRs.

You will know that HR varies day by day for lots of reasons that I won’t go into here. Those variations can be relatively trivial but sometimes not. You will understand that if I ask you to do an interval in HR Zone 4 (HR Z4), you may start too quickly before your heart catches up to your work rate.

You will also have worked out your HR training Zones. Lots of people have lots of different ways of doing this, and I will use Joe Friel’s Zones. Here is how you can work out your zones:

• Zone 1 Less than 85% of LTHR
• Zone 2 85% to 89% of LTHR
• Zone 3 90% to 94% of LTHR
• Zone 4 95% to 99% of LTHR
• Zone 5a 100% to 102% of LTHR
• Zone 5b 103% to 106% of LTHR
• Zone 5c More than 106% of LTHR

His zones are based on LTHR (lactate threshold heart rate), which is the maximum average heart rate you can maintain for 60 minutes. You will need to do a test to determine this, but you can get a good average estimate from the last 20 minutes of a 30-minute race effort. Averaging the last 3k of a recent 5k PB is good enough. Your LTHR should get HIGHER as your training progresses and you get ‘fitter’. Please feel free to increase LTHR whenever your stats tell you to (this will then change your training zones).

I assume that you are a beginner-to-intermediate runner, perhaps some way off achieving a sub-20 minute 5k (the headline that got you here in the first place).

• Monday: 45 minutes at the low end of Z2. +Weights for leg strength. EASY.
• Tuesday: 5 x 6 minutes of effort with 5 minutes rest. The effort is the maximum you can consistently maintain throughout the session. A similar level of effort to your last 5k PB. Your HR may hit Z5a; don’t go higher (If you can’t do 5x, then start at 3x. If you can’t do 6 minutes, start at 4 minutes). VERY HARD.
• Wednesday: 45 minutes Z1. +Drills. EASY.
• Thursday: 15-minute warm-up, then 60 minutes in Z3 to Z4. HARD.
• Friday: Complete Rest. EASY.
• Saturday: 45 minutes at varying speeds and varying gradients. MODERATE.
• Sunday: Long run of 90 minutes. +Core exercises. EASY.

You can find diagrams/resources on weight sessions and drills at https://pinterest.com/the5krunner.

Please feel free to skip any of these sessions. Doing all of them would be quite hard for most people. Aim to do 3-4 sessions per week at first.

You can probably keep on doing this plan month after month. However, it may well get a bit boring! Variety will alleviate any boredom you have, BUT it will also improve your body’s response to exercise…which is a good thing. You might want to vary things by, for example, doing a little less rest than the 5 minutes prescribed on Tuesday.

Let me know how you get on. It will get you to a sub-20 5k. As I said earlier, I’d personally include more focus on pace-based training.

Related reading: Performance & Training Analysis – One-Off Assessment.

Last Updated on 29 August 2026 by tfk the5krunner

tfk the5krunner

tfk is the founder and author of the5krunner, an independent endurance sports technology publication. With 20 years of hands-on testing of GPS watches and wearables, and competing in triathlons at an international age-group level, tfk provides in-depth expert analysis of fitness technology for serious athletes and endurance sport competitors. ID