Running Paces Explained: Easy, Tempo, Threshold and Intervals

A tempo run is a sustained effort at comfortably hard pace, the quickest you can hold for 20 to 40 minutes while still breathing rhythmically. It sits between your easy aerobic pace and your all-out interval pace. Most runners only ever train at one speed, somewhere in the middle, and that grey-zone running is the most common reason they stop improving.

TL;DR

The four paces, defined

Four paces cover almost everything a distance runner needs. Easy pace is conversational running, your aerobic base, and the slowest of the four; this is the Zone 2 work I unpack in our guide to Zone 2 running. Tempo pace is comfortably hard, the effort you could sustain for 20 to 40 minutes. Threshold pace is slightly faster, the intensity right at the point where lactate begins to accumulate faster than you clear it, usually trained in repeats of 8 to 15 minutes. Interval pace is hard and brief: repeated efforts of 30 seconds to 5 minutes with recovery between them, the work that lifts your top-end speed and your VO2 max, which we cover in our plan to improve VO2 max after 40.

How to find each pace

The most reliable gauge is your breathing, not your watch. At easy pace you can speak in full sentences. At tempo you can manage a short phrase. At threshold you can say a word or two. At interval pace you cannot talk at all. Rate of perceived effort works the same way on a 1-to-10 scale: easy is a 4 to 5, tempo a 6 to 7, threshold a 7 to 8, intervals a 9. Heart rate is a useful cross-check once you know your zones, but it lags the effort and, as below, it is the least trustworthy gauge in Singapore.

Tempo versus threshold

These two get used interchangeably, but they are not the same. The physiology underneath is lactate: San-Millan and Brooks showed that as intensity rises, blood lactate climbs and the body shifts from burning fat to burning carbohydrate, and the trained runner pushes that turn point to a higher workload (San-Millan and Brooks, 2018). Tempo sits just under that turn point, which is why it feels sustainable. Threshold sits right at it, which is why it is held in shorter blocks. In practice, treat tempo as the sustainable comfortably-hard effort and threshold as the slightly sharper one you can only hold in repeats.

Running paces in Singapore's heat

A pace chart written for a temperate climate will lie to you here. Heat and humidity raise your heart rate and slow the pace you can hold at any given effort, so a tempo that reads as 5 minutes per kilometre in cool air might be 15 to 20 seconds slower in Singapore at the same true intensity. Chase the pace number and you will push your easy runs into tempo and your tempo into threshold, which is exactly the grey-zone trap. Run by effort and breathing instead, and where you can, train in the cooler pre-dawn or post-sunset windows I cover in our guide to the best time to run in Singapore.

How to escape the grey zone

The fix is a deliberate split of intensity. Seiler's review of how elite endurance athletes distribute their training found a consistent pattern: roughly 80 percent of sessions easy and about 20 percent genuinely hard (Seiler, 2010). The grey middle, where most amateurs live, is too hard to recover from and too easy to drive adaptation. But there is a constraint nobody mentions: holding clean paces, especially the hard ones, demands a body that can absorb the load. Runners who break down never get to run their hard days hard. That durability is built in the gym, which is why we pair pace work with strength training for runners in our personal training for runners. The paces give you the plan; the strength is what lets you keep running it.

Frequently asked questions

Q. What is a tempo run?

A tempo run is a sustained effort at comfortably hard pace, the quickest you can hold for 20 to 40 minutes while still breathing rhythmically. It sits just below your lactate threshold, which is why it feels hard but controlled, and it is the classic session for raising the pace you can hold over a long race.

Q. What is the difference between tempo and threshold pace?

Tempo sits just below the point where lactate starts to accumulate, so it is sustainable for 20 to 40 minutes. Threshold sits right at that point, so it is slightly faster and held in shorter repeats of 8 to 15 minutes. Tempo is the comfortably-hard effort; threshold is the sharper one you can only hold in blocks.

Q. How fast should my easy runs be?

Easy runs should be conversational: slow enough to speak in full sentences, roughly a 4 to 5 out of 10 on effort. Most runners run them too fast. In Singapore's heat, judge easy pace by breathing rather than a number, and accept that it will be slower than a temperate-climate plan suggests.

Q. How many hard running days should I do each week?

For most runners, one to two genuinely hard sessions a week is the ceiling, with the rest easy. That maps to the 80/20 distribution the evidence supports. More hard days than that, without the easy volume and the strength base to absorb them, is how runners stall or get injured.

Citations

San-Millan, I., and Brooks, G. A. (2018). Assessment of Metabolic Flexibility by Means of Measuring Blood Lactate, Fat, and Carbohydrate Oxidation Responses to Exercise in Professional Endurance Athletes and Less-Fit Individuals. Sports Medicine. doi.org/10.1007/s40279-017-0751-x

Seiler, S. (2010). What is Best Practice for Training Intensity and Duration Distribution in Endurance Athletes? International Journal of Sports Physiology and Performance, 5(3), 276-291. journals.humankinetics.com