V02 max (Interval) Runs

Objective:- To increase the amount of oxygen your body can process into your bloodstream, so that increased gains from the aerobic energy system can be achieved

The aerobic energy system will always be the main energy source when the distance is over about 1500m. The source of the energy is carbohydrate and fat stored in your body, but to use it oxygen from your blood supply is essential.  The more oxygen your blood contains, the more use that can be made of your stored carbohydrate and fat. 

For shorter distances (1500m to 5k) VO2 max is the most important physiological variable that affects race results. It’s also important for longer races, but not as important as the Lactate Threshold (For which Tempo runs are the most effective way to train). Nevertheless training to improve your oxygen intake and its use will affect endurance for all distances.

V02 max is the maximal amount of oxygen your heart can pump to your muscles that your muscles can use to produce energy. Three factors determine it:-

  1. Your maximum effective heart rate
  2. The amount of blood pumped per heartbeat
  3. The proportion of the oxygen in your bloodstream that can be used by your muscles

Both your genetics and your training will affect how high your VO2 max is. You cannot do much about your maximum heart rate, but you can work on the other two factors. Training can improve VO2 max, but the rate of improvement will slow as you reach your genetic potential. In other words, those new to run training can make bigger gains in VO2 max than those who have been training intensely for years. Older runners need to tailor these runs most carefully.

How fast and how far?

If you are well trained, you will be able to maintain your VO2 max pace for about 8 minutes and 95% of VO2 max pace for 15 minutes. (Typically slightly faster than 3k or 5k race pace). The highest stimulus to improve aerobic capacity is when 95% to 100% of VO2 max is maintained throughout the run. However while you might maintain this level for one run, repeating the same several times will not be possible or desirable. So the distance that you should make in one constant run is always less than one that takes 8 minutes.

After each VO2 run, which we will now call each Interval, recovery is essential. Resist the temptation to bend over with hands on knees as you will, though it might not feel like it, recover most quickly when you jog. If you cannot jog but have to walk, you are probably going slightly too hard. Recovery time after each interval will vary depending on the time taken to run the interval. It should be between 90 secs after 2 minute intervals to 3 minutes for 5 minute intervals.

The total distance that should be run at VO2 pace is about 5k per training session. So knowing the total distance to be run at VO2 pace points to the link between interval length and frequency.

It is common to refer to intervals as IT.

Length of interval

Number of intervals

Distance at VO2 pace



4,800 to 6,000m



4,800 to 8,000m



5,000 to 8,000m



4,800 to 7,200m



4,800 to 8,000m

So an interval session of 8km with 5x1000m IT, 200m jog between; means a total run length of 8km, which includes an easy or steady run to warm up before the intervals and an easy run to warm down at the end. After the warm up run, a 1000m interval run then 200m jog then 1000m interval run then 200m jog until after the 5th 1000m interval the warm down easy run.

It is only necessary to carry out one Interval training session per week. While you are running intervals, it is most likely that at the start of an interval you will be more out of breath than you were at the start of the previous interval, similarly at the end of the interval. So by the final interval you might be gasping! Thats fine. However, the intention is that you will be able to complete all of the intervals in a session. If you find you cannot complete all of the intervals in a session, then next time slow down a little for all of the intervals.

Graeme Loudain – September 2019

These notes are published as a general aid to all endurance runners. They are guidelines based on current best practice, intended to illustrate the points in the articles rather than provide a precise training schedule. They are written in a way to be of help to runners. Individuals will have their own requirements and the content of the notes will not suit all. Please use them in the spirit in which they are intended and modify them to suit your own needs. If you have suggestions for improvement, amendments or comment, please email gladmin@btinternet.com.