What it is
A tempo run is a sustained effort held at your lactate threshold — the intensity above which lactate builds up in your blood faster than your body can clear it. Below that line you can hold a pace almost indefinitely. Above it, a clock starts running, and how long you last is measured in minutes.
In practice it means 20 to 40 minutes of continuous "comfortably hard" running, sandwiched between a proper warm-up and cool-down. It is the classic hard session of distance training, and if you only add one workout to a week of easy running, this is usually the one to add.
Why it works
Threshold is the most trainable thing in distance running. Your maximum oxygen uptake has a fairly low ceiling and moves slowly; the fraction of it you can sustain moves a great deal.
Tempo work improves that fraction from both directions. It increases how much lactate your muscles and heart can take back up and use as fuel, and it improves the enzymes and transporters involved in clearing it. The net effect is that the line moves — the pace that used to feel like the edge becomes the pace you can sit at.
That matters because for anything from 10k upward, your threshold pace is essentially what governs your race. Raise the ceiling and everything below it gets easier at the same time.
How to pace it
- The talk test. You can say a short phrase. You cannot say a sentence, and you definitely can't hold a conversation.
- Effort. 6–7 out of 10. Hard, but under control — you could go a bit faster and are choosing not to.
- Heart rate. Roughly 80–90% of maximum.
- Race-pace shorthand. Close to the pace you could race for about an hour. For most runners that's somewhere between 10k and half-marathon pace.
If you're guessing, guess slow. A tempo run 10 seconds per mile too slow is still a good tempo run. Ten seconds too fast turns it into a mediocre interval session that you'll abandon halfway.
Two sample sessions
Continuous tempo. 15 minutes easy warm-up, 20 minutes continuous at threshold effort, 10 minutes easy cool-down.
Cruise intervals. 15 minutes easy warm-up, then 3 × 10 minutes at threshold with 2 minutes of easy jogging between, then 10 minutes easy cool-down.
Cruise intervals are the more forgiving of the two, and often the smarter choice. The short breaks make it much easier to hold the correct effort for the full 30 minutes of work rather than drifting upward and dying, and the training effect is close to identical.
Where it fits in your week
Once a week is plenty; twice is the ceiling for experienced runners in a build phase, and only with easy days in between.
Put it early in the week, keep the day before easy, and keep the day after easy or off. Don't schedule a tempo run within two days of a long run you actually care about.
Beginners should have several months of consistent easy running behind them before adding tempo work. It isn't dangerous, but it's wasted on an aerobic base that isn't there yet.
Common mistakes
- Running it at 5k effort. The single most common error. A tempo run should end with you thinking you could have continued. If you're counting down the last five minutes, you ran an interval session with no recovery.
- Jumping straight to 40 minutes. Start at 20 and add five minutes every couple of weeks. The duration is the progression.
- Skipping the warm-up. Threshold effort from cold is both unpleasant and slower. Fifteen easy minutes first makes the whole session better.
Track it in Kamee
Track it with GPS and watch live pace through the tempo block — this is the one session where the number genuinely helps, because holding a steady effort by feel is hard the first few times. Afterwards, check the splits across the block: you want them flat. A tempo that starts fast and fades by 20 seconds a mile was run at the wrong intensity, not the wrong distance.