VO2-max intervals aim to enhance your maximum . Research continually discovers new methods, but overall, the key factor for VO2 max is the ability to transport as much oxygen as possible to the muscles.
The heart plays a central role, suggesting you’ll boost your , by training your heart to be larger and stronger.
In VO2-max intervals, it's crucial to monitor your , as it reflects heart workload. With enough high heart rate minutes in a session, the heart becomes larger and stronger, circulating more blood.
To maximize your intervals, target zone 4 or 5 (if you’ve established zones with a test). If not, aim for over 90% of max heart rate.
You can approach VO2-max intervals in various ways. No one method is superior—all three approaches below yield improvements. I recommend varying interval choices.
Long intervals with long breaks
- 3-5 minute intervals
- Long breaks – at least 3 minutes!
Long VO2-max intervals typically last 3-5 minutes. Run them in several ways but try to pace so you complete all planned intervals properly. Avoid running too fast initially and struggling later.
Intervals can start fast then settle into a steady pace, or maintain a constant pace. Starting hard accelerates oxygen uptake but risks not completing intervals properly – experiment, and remember a high heart rate is crucial in VO2-max intervals.
Typical pace for long intervals is around 5 km pace for experienced runners. Beginners need not worry about a specific pace – just manage effort as described.
Examples of long intervals:
- 6 x 3 minutes with 3-minute breaks
- 4 x 4 minutes with 4-minute breaks
- 3-4 x 5 minutes with 4-minute breaks
Short intervals with short breaks
- 20-60 second intervals
- Half the interval length for breaks
Short intervals with short breaks are another effective form to enhance oxygen uptake. They allow slightly higher speed than long intervals – specifically recommending “VO2max” speed, equating to zone 5 for those tested. Without defined zones, run by feel – aim to run as fast as possible (while maintaining the same pace across all intervals).
The approach is simple:
- For long intervals, breaks should feel LONG ENOUGH
- For short intervals, breaks should feel TOO SHORT
A single short interval won't elevate heart rate to the desired zone, but “too short” breaks prevent it from dropping enough, gradually increasing heart rate.
Examples of short intervals
- 30 x 30 seconds with 15-second breaks
- 20 x 40 seconds with 20-second breaks
- 15 x 60 seconds with 30-second breaks
Sprint intervals
- 30-60 second intervals
- Long breaks (3-5 minutes)
Short and long intervals mentioned above are the most common VO2-max intervals. However, research on sprint intervals indicates they can effectively boost your fitness score. Be cautious with frequent use due to high intensity.
Sprint intervals are straightforward: Run ALL OUT. As fast as you can!
Since intervals are all-out, long breaks are necessary. Typically, breaks are 3-5 minutes, even if intervals are under a minute – often around 30-second intervals.
If breaks are too short, you won't be fully ready, lowering interval intensity, which isn’t ideal. Ensure breaks are long enough. Track that you cover the same distance in all intervals – confirming intensity is maintained.
Examples of sprint intervals
- 6 x 30 seconds with 4-minute breaks
- 4 x 45 seconds with 5-minute breaks
References
- Bassett DR Jr, Howley ET., Limiting factors for maximum oxygen uptake and determinants of endurance performance (2000)
- Anderson Owen, Running Science (2013)
- Koral J, Oranchuk DJ, Herrera R, Millet GY. Six Sessions of Sprint Interval Training Improves Running Performance in Trained Athletes. (2018)
