VO₂max intervals
Repeats of two to five minutes at around the pace you could hold flat out for ten minutes, with equal or slightly shorter recoveries.
Also called: I-pace intervals, 1000m repeats.
The classic aerobic-power session. Reps are long enough to drive oxygen uptake near its ceiling — that takes roughly two minutes of hard running, which is why 30-second efforts do not do this job — and the recoveries are short enough that you start each rep with your oxygen uptake still elevated. Total work sits in the 15–25 minute window. Going beyond that mostly buys fatigue, not adaptation.
The session
Shown at a 4:00 marathon reference — 1 h 05 total, about 10.2 km, including 21 min of quality work.
Warm-up
- 12 min easy (6:43–7:24/km)
- 4 × 20 s strides, jog back between
Main set
- 4 × 1000 m @ 4:48/km (5K) — 4:48, 115 s/400 m lap, 5 min jog between
Cool-down
- 10 min easy (6:43–7:24/km)
Why this session works
Reps of 2–5 minutes at ~5K pace accumulate time near VO₂max — the strongest single stimulus for aerobic power. Jog recoveries keep oxygen uptake elevated into the next rep.
Source: Billat 2001; Daniels 2014. Training phase: build.
Run it at your own paces
Open the workout generator and enter a recent race time — every rep length, recovery and target pace is recalculated for your fitness, and the session exports to .fit for a Garmin watch.
Frequently asked questions
What is a vo₂max intervals?
Repeats of two to five minutes at around the pace you could hold flat out for ten minutes, with equal or slightly shorter recoveries. The classic aerobic-power session.
How long is this session?
At a 4:00 marathon reference it comes to 1 h 05 and about 10.2 km, of which 21 min is prescribed quality work. The generator scales both to your own paces, so a faster runner covers more ground in the same time.
Who is this workout for?
It is written for the build phase of a marathon build. The distances shown suit a 4:00 marathoner; enter your own recent race time in the generator and every rep length and target pace is recalculated for you.
More vo₂max intervals sessions
- Cutdown intervals — Intervals that get shorter and faster as the session goes on.
- Pyramid intervals — Reps that climb in length to a peak and then come back down.
- 30/30 intervals — Thirty seconds hard, thirty seconds easy, repeated — accumulating time near VO₂max without the strain of long reps.
- Hill repeats — VO₂max-effort intervals run uphill, with the gradient supplying the resistance and capping the impact.