Heart rate monitors: how to use them to improve your run

Unsure how to train with your heart rate monitor and get the maximum benefit from its data? Joe Friel explains how to train effectively and efficiently with a heart rate monitor, using heart rate zones

Joe Friel explains how to improve your run by using a heart rate monitor

There are key areas that’ll ensure you make the most of your heart rate monitor (HRM) with the first being to accurately calculate your training zones by determining your functional threshold heart rate (FTHR), both of which we show you how to calculate at the bottom of the page. Tied in with this, never use 220 minus age or maximum HR to set zones – they’re not good markers.


I’d also recommend, after a run session, comparing run speed with average HR by dividing HR by speed. You can do this for the entire run or sections of it. This number is called the ‘Efficiency Factor’ and rises as your aerobic capacity increases. It’s a great marker of perhaps the most important aspect of the endurance athlete’s fitness.

Note, too, that once your fitness has progressed beyond a beginner’s level, HR zones will seldom change and never by very much. In fact, you don’t necessarily want them to change. What should change is pace and speed. So pace zones and HR zones will rarely match.

When it comes to really boosting stamina, undertake maintenance runs at your aerobic threshold (AT). These are at least weekly in the base period (winter into early spring) and at least once every two weeks in the build period (spring into the triathlon race season).

Unless you have access to a lab, assume that AT is 30bpm below FTHR, plus and minus 2bpm. For example, if FTHR comes in at 152bpm, AT is estimated at around 120-124bpm. Long, steady runs in this HR range are highly effective in boosting aerobic fitness.

All that said, never take HR to be a predictor of performance. It isn’t. No triathlon race outcomes are ever determined by who has the highest HR. On the other hand, speed is the perfect indicator of performance.

Functional threshold test

Run a 30min time-trial on your own

Find your FTHR

At 10mins into your 30min TT, click the lap button on your HRM

When finished, look back to see your average HR for the last 20mins. This is an approximation of your FTHR

 Set zones 

You can now set your run training zones. Zone 1 is less than 85% of FTHR; zone 2 85-89%; zone 3 90-94%; zone 4 95-99%; zone 5a 100-102%; zone 5b 103-106%; zone 5c more than 106%