What a tempo run actually is (and how to pace one)

Of all the workout names runners throw around, “tempo run” is the one people most often do wrong — usually by running it too hard. A tempo isn’t a race, and it isn’t an all-out effort. It’s a specific, slightly boring kind of discomfort, and that precision is the whole point.

What it is: comfortably hard

A tempo run is a sustained effort at roughly your lactate threshold — the pace you could hold for about an hour if you had to. The classic description is “comfortably hard”: hard enough that chatting is down to short phrases, not sentences; controlled enough that you could keep going. If you’re gasping, you’ve turned it into a race. If you could sing, you’ve turned it into an easy run.

A typical tempo is 20 to 40 minutes at that effort, sandwiched between an easy warm-up and cool-down. Some coaches break it into a few longer intervals with short breaks (cruise intervals) — same idea, slightly more forgiving.

What it does

The tempo trains your body to clear lactate as fast as it produces it, which is another way of saying it raises the pace you can hold before your legs flood and slow. Threshold is one of the most trainable qualities in distance running and one of the most race-relevant — nudging it up is how your goal pace starts to feel easier. For 10K, half, and marathon runners, the tempo is the bread-and-butter quality session.

How to pace it

Threshold pace sits a little slower than your 10K race pace — very roughly 25 to 40 seconds per mile slower than 5K pace for most runners, though it varies. If you’ve raced recently, the cleanest way to find your number is to work from that result: a pace calculator will turn a recent race into equivalent paces, and your tempo lives just easier than your 10K line.

But the number is a starting point, not a master. On the day, run to effort: comfortably hard, holdable, controlled. If the pace that used to feel like threshold suddenly feels like a race, your body is telling you something the calculator can’t — usually that you’re under-recovered and today isn’t the day to force it.

The mistake: racing your tempo

The tempo run’s job is to be repeatable. Run it at 95% and you can do one a week for months, improving steadily. Run it flat-out and you’ve done a race — you’ll need days to recover, you’ll compromise your other sessions, and you’ll get less from more. The discipline of holding back on a tempo is exactly the discipline that makes you faster. Ego says push. The training says hold.

When to do one — and when not to

A tempo belongs on a day you’re reasonably fresh. Stack it on top of a bad night or a heavy training week and you’ll hit tempo effort at a slower pace, get less benefit, and dig yourself deeper. Knowing which mornings can absorb a hard session — and which can’t — is the difference between a plan that builds you and one that grinds you down. That judgement, made every morning from your sleep, heart rate, and recent load, is what Faster is for. It’ll tell you when today is a tempo day, and when the honest move is to run it tomorrow. See also: should I run today?