Heart Beat: Finding Your Threshold Heart Rate

We've already highlighted the difficulties of trying to establish your maximal heart rate. Now you’ve mastered that, here’s another problem: once you’ve found your true maximum, how do you know exactly what heart rates you should be training at? We often see round figures quoted in general guides, ranging from 70-90 per cent of MHR. Unfortunately, the reason they’re so vague is that – as we’ve found out – we’re all different.

In the early days, you’d have needed a physiological lab test to find the right percentage for you. In the 80s, however, an Italian physiologist called Francesco Conconi developed a test to make things a little more convenient. It was designed to pinpoint the ‘threshold intensity’. This is among the most popular – and certainly fashionable – training zones, used for quality aerobic workouts.

The Conconi test was developed using 210 runners, and centres on the principle of increasing heart rate with increasing intensity, or speed. What happens is that you run progressively faster during the test (see below) and your heart rate increases in a linear fashion until it plateaus a little. If you plotted your heart rate against speed on a graph, there would be a clear point at which the gradient of the line changed. This is referred to as the deflection point, and is said to be the threshold. It is, therefore, this heart rate that you should use for your threshold sessions.

After the original work on runners in 1982, further studies applied the test to other sports, and it soon became popular with cyclists, swimmers and canoeists. The beauty of the test is that it can be carried out in the normal training environment and is specific to each individual, rather than generalising by age or any other factors.

The threshold intensity is the sort of pace that you use for a tempo run of 20-25 minutes, preceded by a warm-up and followed by a cool-down. You can also split the work into reps, common examples being 4-6 x 1 mile with a couple of minutes’ recovery. The intensity will not be far off 10K pace, but is certainly a little faster than marathon race pace. This gives you a reasonable-quality session, so much so that you would aim to use it only once or twice a week.

However, getting the intensity right is vital. If you go too slow, you’re not training as hard as you might; but go too fast, and your session changes from an optimal aerobic workout to more of a hard slog, in which anaerobic metabolism plays a greater part.

There’s been a good deal of analysis of the Conconi test, and not all of it has been positive. Tests often fail to find a true and distinctive deflection point that is repeatable and reliable. In some individuals there is no obvious deflection point, and in others it’s ambiguous at best. If this applies to you, don’t worry, we’ll be explaining alternative methods in future issues. As with all tests and measures, give it a try, but remember that even the best aren’t completely foolproof.

Performing A Conconi Test

Ideally, you need a heart rate monitor that will record and store heart rate information for assessment afterwards. Alternatively, take along a partner who can write down your measurements as you give them. Perform the test on either a running track or a treadmill. NB: This is an intense test – only perform it if you’re in good physical health.

  • Warm up thoroughly, as you would for a race or track session
  • Your starting pace should be about 70 seconds for 200m (or 10km/h on a treadmill)
  • Once started, you need to increase your pace each and every 200m
  • At each 200m point, press the store button on your HRM (or tell your partner your rate)
  • Speed increase should be about 2-3 seconds per 200m (or 0.5km/h on a treadmill)
  • Keep going until you can’t increase your pace
  • Jog gently afterwards to cool down gradually
  • Plot your heart rate on a graph, against speed
  • Find the deflection point