How fast should I run?

As a coach, one of the most frequent questions I get is, ‘How fast should I run?’ I’ve found that the best way to get an accurate answer is by doing a test of your lactate threshold, or the pace at which your body can no longer clear lactate at the rate it’s being produced.

Although there are many ways to determine your lactate threshold, most are expensive and inconvenient. In contrast, the DIY test I use is easily reproducible, cost-free and reasonably accurate. I call it a ‘Run LT Field Test’. All you need is a track or a GPS device to determine total distance run, and a heartrate monitor. The Run LT Field Test entails a timed eight-minute run on a 400m track or, while wearing a GPS device, on a measured flat surface. The goal is to cover as much distance as possible in the eight minutes. Data collected in the test includes:

  • Total distance run (to the nearest 10m)
  • Average heartrate during the test
  • Maximum heartrate during the test
  • Each 400m split time
  • Heartrate at the end of each 400m
  • Perceived exertion on a scale of one to 10
  • Where you ran the test
  • Weather conditions

The true test of fitness

Follow the instructions below, then use your results combined with the chart at the bottom of the page to guide your training

1. Find a test track

Go to a quiet track to conduct the test, running on the inside lane. Always do the test at the same time of day and, if you’re not using a track, do it on the same stretch of road; repeatability is important for accurate testing. Also, make sure the wind is calm and temperatures are mild.

2. Warm up

Do your normal pre-race warm-up, including some strides, so you’re ready to run hard from the beginning of the test.

3. Start the test

Start your test in lane one. Don’t go out too fast; you want to find the fastest pace you can sustain for eight minutes. Focus on finding your rhythm and pace. It will be faster than your 5K race pace and, for most people, slower than mile race pace.

4. Keep track of your time

Take your splits at each 400m and measure your final distance to within 10m. Keep track of the time. Note all the data in your training diary. Record and date all your results to compare and mark your progress.

5.  Use your data

Take the average heart rate during your eight-minute field test and multiply it by the percentages in the table (left). Once you have computed your results, you can begin to use the heart rate ranges in training and racing to ensure you’re working at the proper intensity. Repeat this test several times a year to track your lactate threshold and fitness improvement.

% of your average heart rate


Recovery run

Steady state run

Tempo run

Fartlek intervals

Hill intervals

Track intervals