What pace should VO2max intervals be?

Roughly 3K to 5K race pace. If you can hold the pace for the whole session comfortably, it is too slow. If you are dying on rep three, it is too fast.

How many intervals should I do?

Total hard volume of 4 to 6km per session for most runners, and no more than about 8 percent of weekly mileage. Five to six reps of 800m to 1000m is a typical full session.

How long should the recovery be?

Roughly equal to the rep, or slightly less, as an easy jog. The point is to start the next rep able to hit the pace, not to be fully recovered.

No. Intervals by time work just as well on any road or path. A track makes it easier to learn pacing, which is genuinely useful early on.

Guide

VO2max intervals, and when they are worth it

Intervals are the most satisfying session in running and the most over-prescribed. They raise your aerobic ceiling, which is real and valuable, but they are the smallest and most expensive part of a well-built week.

What they do

VO2max is the maximum rate at which you can consume oxygen. Training near it, which means running at roughly 3K to 5K race pace, is the most direct way to raise it.

The mechanism requires time spent close to maximum oxygen uptake, and it takes about 90 to 120 seconds of hard running to get there. That is why the classic interval is 3 to 5 minutes: shorter reps spend most of their duration climbing toward the intensity rather than sitting at it.

The sessions

Total hard volume of 4 to 6km, or roughly 12 to 20 minutes, is a full session. Daniels caps VO2max work at about 8 percent of weekly mileage for good reason.

5 x 1000m. At 5K pace, with 2 to 3 minutes jog. The default session and hard to improve on.
6 x 800m. At slightly faster than 5K pace, with 2 minutes jog. Good for runners who need turnover.
4 x 5 minutes. By time rather than distance, at 5K effort, with 3 minutes jog. Works anywhere, no track needed.
3 x 8 minutes. At about 10K pace. Slightly lower intensity, longer time at it. A useful bridge from threshold.

When to do them, and when not to

For 5K and 10K training, weekly through the build phase. For the half marathon, every second week, with threshold carrying the load. For the marathon, mostly in the base and early build phases to maintain the ceiling, then largely replaced by marathon-pace and threshold work in the final six weeks.

They are the first session to cut when you are tired, carrying a niggle, or short on sleep. The injury risk per unit of fitness is higher than any other session in the plan, and the fitness they buy is the fastest to come back later.

Why more is worse

VO2max responds quickly and plateaus quickly. Six to eight weeks of consistent interval work takes most of the available gain, and doing three interval sessions a week instead of one does not triple the benefit. It roughly triples the recovery cost and the injury risk.

A runner stuck at a plateau who adds a second and third interval session almost always gets slower over the following two months. The lever that is actually available to them is usually more easy volume.

Frequently asked

What pace should VO2max intervals be?: Roughly 3K to 5K race pace. If you can hold the pace for the whole session comfortably, it is too slow. If you are dying on rep three, it is too fast.
How many intervals should I do?: Total hard volume of 4 to 6km per session for most runners, and no more than about 8 percent of weekly mileage. Five to six reps of 800m to 1000m is a typical full session.
How long should the recovery be?: Roughly equal to the rep, or slightly less, as an easy jog. The point is to start the next rep able to hit the pace, not to be fully recovered.
Do I need a track?: No. Intervals by time work just as well on any road or path. A track makes it easier to learn pacing, which is genuinely useful early on.

Stop reading. Start training.

This is the theory. Shed is the schedule.

Knowing what a threshold run is for does not tell you which Tuesday to run one, or how fast, or what to do when you miss it. Shed writes every session of your race block and adjusts it as you train. Ask it where a number came from and it will tell you.

Get your plan on iPhone