VO2 Intervals

VO2 intervals are one of the best ways to improve distance running. If you want to get faster then max out your oxygen use.

VO2 intervals are the most important fast session in my running plan. This is a run not to skip.

As with all running there a multiple ways to reach the same goal. This is the approach I am taking and what tends to work well for many.


The intensity you want to work at is close to your maximal oxygen uptake (VO2max). Aiming for 95-100% of VO2max. But it is ridiculously hard and expensive to measure your VO2 while out running. We need another way.

Heart rate can help. Typically hitting between 90-100% of maximal heart rate (HRmax) gets you in the right area. But not always. Heart rate can plateau while your intensity rises and you may be working harder than required. Also your HR may not rise to the desired range at the start of the session.

Using pace can be a little more accurate. You will be aiming for between 5000m to 3000m race pace. The slower you race times the more you would lean towards 3000m pace. Another way to think is we can only hold our VO2max speed for between 9-14 minutes. That is the pace and intensity of the intervals.


The interval length should be between 2-6 minutes. Most studies have shown between 3-5 minutes giving the greatest results.


Recovery is designed so you can perform your next interval. We want to avoid early fatigue.

Many sources will give a ratio for recovery such as 2:1 or 1:1, which appears to work in the research. My preferred approach is to take between 3-5 minutes between intervals. Shorter than 3 minutes tends to drop the standard in the last couple of intervals. Beyond 5 minutes seems to reduce the overall effectiveness of the session.

Keep the intensity at a comfortable run. Below anaerobic threshold. At your usual easy run pace. Walking and slow jogging will work, but I find if you can keep the speed up a little bit it helps reset your comfortable to a higher level.

How Many?

For the greatest improvements it appears we need between 12-30 minutes of intervals. Exactly how much may be dependant on your current fitness. If you don’t have the ability to maintain the intensity beyond 15 minutes, then there is no point forcing it out to 30 minutes.

If already to some degree of running around VO2max, then start with 4 x 3min intervals. From there you can gradually add time. For example:

  • 4 x 3min (12min)
  • 5 x 3min (15min)
  • 3 x 5min (15min)
  • 4 x 4min (16min)
  • 6 x 3min (18min)

For those who haven’t got a strong running base, have had some time off or haven’t included running at these pace a more conservative start might be better. Starting with 4 x 2min or even less and building up from there would help ensure the connective tissue and muscles are better able to handle VO2 intervals.

VO2 Interval Session

Ideally you won’t be feeling stuffed from previous training. A day or two of comfortable running would be best leading up. Make sure you are hydrated and fuelled lightly. These are not the types of runs to testing out any depletion strategy.

Warm Up

Warm up well. Treat it is an opportunity to fine tune your warm up for races. I like to run easy and relaxed for 10-15min until my body feels ready. Then I’ll either gradually increase the speed, or throw in a few relaxed run-throughs at speed. Nothing is forced, but I am looking feel the natural snap and spring from running faster. Total warm up time is usually 20-25min.

Main Set

Straight into the first interval. The paradox of trying to feel relaxed while pushing up the speed. Aiming to get the pacing spot on at the start. Making small adjustments as to be as exact as possible. Ideally you can hold the same pace from the start through to the end of interval. Then keep up that pace for each interval.

At the end of the interval relax into the recovery. Resist the urge just to stop or walk. Make the most of the momentum and keep the legs moving. Relax with each breath and reset the mind ready for the next interval.

Focus on the key elements of your running stride. Push through the ground. Keep the snap and lightness in each step. Stay away from muscling through. Beware the laziness of the body. It looks for the easy way out in the short term. Keep your technique, speed and power. Teach your body to maintain the efficiency of speed.

Cool Down

Once all the intervals are completed ease into a relaxed jog for the cool down. I like to start super easy and gradually build the pace back up over a few minutes to a run that feels moderate. Then hold that for a further 10 or so minutes before easing back down over a further 5-10 minutes seems to have me feel fresher over the next day than if I just jog easy or do a really short cool down. I have no science to support this. Just years of trying different methods.

VO2 Intervals

  • Warm up 10-15min easy running then 5-10min faster running
  • 4-8 x 2-6 minutes at 95-100% VO2max / 90-100% HRmax / 5000m-3000m race pace
  • Recovery between each interval 2-4 minutes easy run
  • Cool down for 10-20min

New Running Plan

Over the last four weeks I have experimented with my run training. I haven’t followed a normal training program. Instead I’ve tested how I respond to different types of run sessions. This has led to a new running plan.


Why Have I Experimented?


I have a goal to regain my running form from younger days. Looking to challenge my marathon personal best.

At 40 years old I cannot do the same training that got me there. The training I have been doing over the last couple of years won’t get me there either. Changes need to be made.

So I took some time to test the effect of different runs.



Key Lessons?


The higher volume, slower running that has been a mainstay of ultra marathon training has changed my over running style. Muscle imbalances have built up over time and my body is less able to handle fast running.


Anaerobic threshold runs raise my fitness quickly, but the down side is strong. My sleep quality gets effected. Three days later I tend to feel extra flat and struggle to run any quality for a couple of days


Fast running broken into intervals is improving all my running at all speeds. The greatest effect is when I keep the volume at a level that doesn’t bury me in the session. Where I feel like I can do at least one more repeat.


The Result


Less volume and more speed supplemented with strength training.


Running Plan


9 day training cycle:

  1. Short and Easy run (30min)
  2. Steady Run 45-60min
  3. VO2 Intervals 400m-1200m with 3min recovery (total 2-6km of intervals)
  4. Easy Run 45-60min
  5. day off (sleep after night shift)
  6. Long Intervals 2-4km at Marathon to Half Marathon pace with 5-2min recovery
  7. Easy Run 45-60min
  8. Long Run of 2 hours (slower than marathon pace, but far from a slow jog)
  9. Easy to Steady Run depending on how I feel.


Mixed amongst this week will be strength training. Two dedicated session out of each 9 days focussing on legs and core. Upper body will be mixed amongst life, without a set session. For me this allows me to get more work in than if I try to set more specific times.


How To Run


Quality is the priority. Hitting the targeted paces in the right way is more important than getting in another repetition or running an extra kilometre. To a point the aim is to get the speeds right then follow up with volume as my body adapts. Both volume and pace will adapt over time. They play off each other. As a result I will review the program every 4 weeks.

This training program is backed by the concepts I have covered in following posts:


Let me know what you think or if you have questions.