The Top 3 Interval Sessions to Boost Your VO2max

vo2max intervals in cycling

Doing ineffective intervals sucks. Especially, when you try to improve your VO2max. They might be hard but don’t cause a sufficient stimulus. You get tired, but eventually not stronger or faster. 

If you want to improve your VO2max, you need intervals that challenge your aerobic capacity. Although training responses to intervals differ across individuals, looking at what the science has to say is a good start. 

So here are my top three well-researched and easily implementable VO2max interval sessions. We will review each and I give you my take based on my experience as a coach and an athlete.

1. Intermittent Exercise Intervals

Intermittent intervals are alternating short bursts of very high intensity with a short period of low intensity. An excellent example of these micro intervals is Billat’s 30/30 intervals.

Veronique Billat is a French physiologist. Her research about endurance performance is invaluable for our understanding of cycling training today.

Billat devoted years to figuring out more effective interval training. She started with a 3-minute interval protocol at VO2max. And finally, she progressed to what is known today as Billat 30/30 intervals. 

You alternate 30 seconds at 100% VO2max with 30 seconds at 50% interval power. During the 30 seconds off your metabolism is still ramped up to VO2max for a significant amount of time. You get a 1-minute interval for just 30 seconds of effort. Try to gain 15-30 minutes total at 30-30 intervals to create a useful stimulus. You can read more about why and how to do 30/30 intervals here.

Rønnestad, however, came up with 30/15 intervals. The idea is by cutting the break to half you gain more time above 90% of VO2max or max heart rate. But, the study has limitations by comparing 3x13x30/15 with 4×5 minute intervals. That’s comparing 19.5 minutes of higher power output to 20 minutes of lower power output. Or metabolically, you compare 29.5 minutes of work with just 20 minutes of work. No surprise the 30/15s come out on top.

In my experience, some athletes have problems completing 30/15s. For example, I send some of my athletes to the lab to find their “exact” VO2max power. Afterward, they perform the 30/15s at VO2max power on the road. Sad to say, they weren’t able to complete the entire set with the prescribed power. Therefore, I suggest performing 30/30s that can be completed with the target power. But of course, if the 30/15 feels fine then go for it.

How do you find the right intensity for microbursts? Well, for the 30/30s you can use your 5-minute peak power, and if the 30/15 feels problematic try to go at 95% of your 5-minute peak power.

The VO2max Microbursts: 30/30 and 30/15 Intervals

  • Warm-up: Perform a warm-up of 15-20 minutes
  • Mainset for Beginners: 2x8x30/30 at 30 seconds at 130-140% of FTP, 30 seconds at 50-60% of FTP
  • Mainset for Intermediates: 3x8x30/30 at 30 seconds at 130-140% of FTP, 30 seconds at 60-65% of FTP
  • Mainset for Competitive: 3x10x30/30 at 30 seconds at 130-140% of FTP, 30 seconds at 60-70% of FTP
  • Recovery in between sets: Try a 1:1 or 2:1 work-rest-ratio, so if your set takes 10min to complete, ride easy for 5-10min in between
  • Cool down: Ride easy to let the workout sink in

Varying your power output during HIT intervals seems like a good strategy to gain more time above 90% of your VO2max. Therefore, I’d like to introduce you to two new interval styles that might work better than constant power intervals.

2. Alternating VO2max Intervals

In two recent studies by Rønnestad and colleagues cross-country skiers had to perform 5×5 minute intervals differently. Subjects either had to go for a constant pace interval or a 90-second fast start followed by 3.5 minutes at a slightly lower power. The fast start intervals resulted in more time over 90% of VO2max and a higher VO2max peak compared to the constant intervals. Surprisingly, subjects didn’t perceive the fast start intervals harder than the constant intervals.

You might wanna try the following workout

  • Warm-up: Perform a warm-up of 15-20 minutes including
  • Mainset 5min: 5×5 minutes at 90sec 115-125% of FTP, 3.5min at 105-110% of FTP
  • Recovery in between sets: Try a 1:1 work-rest-ratio, so 5min easy
  • Cool Down: Ride easy to let the workout sink in

On the other hand, a study by Bossi and colleagues compared constant 5×5 minute intervals at 84% of maximum aerobic power (MAP, about 5min peak power) to the following alternating 5×5 minute intervals in cyclists, now called Bossi intervals:

  • 30sec 100% MAP
  • 1min 77% MAP
  • 30sec 100% MAP
  • 1min 77% MAP
  • 30sec 100% MAP
  • 1.5min 77% MAP

The Bossi intervals resulted in higher VO2peak and more accumulated time above 90% of VO2max, 410 sec total compared to 286 sec in the constant power group. When we look at the intensity of the Bossi intervals 77% of MAP for most cyclists is around threshold. You alternate between VO2max and threshold. Due to VO2 kinetics the surges followed by threshold might cause a faster ramp up to VO2max. Additionally, from my experience my athletes like the Bossi intervals because you break up the interval in chunks, and some cyclists just hate to push a high power consistently.

However, there’s one limitation of the study. Usually, studies use a max effort approach, meaning you try to average the highest power possible across all efforts. The max-effort approach might result in a higher average power. I give you an example. My 5-minute best is 485 watts. If you take 84% you get a 408 watts target for the constant intervals. Now, when I go out and smash some 5×5 intervals I average more like 420-430 Watts across all intervals.

3. Long VO2max Intervals

The last VO2max workout I want to share with you is long intervals. Long intervals for me mean 8-10 minutes. The 8-10 minute range is well-researched in studies by Seiler and Sandbakk. On the one hand, Seiler compared the 4×8 intervals to 4×4 and 4×16 intervals. In this study, the 4×8 minute intervals came out as the clear winners in terms of a higher VO2max and a higher power at 4mmol/l blood lactate.

On the other hand, Sandbakk compared short intervals (2-4min) to long intervals (5-10min) in junior cross-country skiers. The long intervals in this study lead to an increase in VO2max and fractional utilization of VO2max at the threshold (%VO2max at FTP).

So, it seems like if you drop the intensity slightly and you go longer, you get a better training stimulus. Or to put it differently, 32 minutes at a lower intensity worked better than 4x4min at a higher intensity.

  • Warm-up: Perform a warm-up of 15-20 minutes
  • Mainset: 4×8 or 3×10 minute intervals 105-110% of FTP – Goal: Highest sustainable power across all efforts (20-minute best effort might be a good starting point)
  • Recovery in between sets: Try a 2:1 or 1:1 work-rest-ratio, so 4-8min easy
  • Cool down: Ride an easy endurance pace to let the workout sink in

A Word on Simplicity

While the presented workouts seem like better options to increase VO2max they’re not mandatory. I’m a huge proponent of simplicity and I like to go out and simply repeat a certain set of intervals till I’m done. To give you an example I have a steep three-minute climb close to my apartment. One workout I really enjoy is a 6x3min + 4x2min VO2max session. A VO2max session like this is something I can repeat weekly. Now, I could tie myself to Zwift and suffer through the Bossi Intervals, complain about missing a longer climb or simply enjoy the steep climb nearby.

The point of interval training is using sessions that can be repeated forever and not about finding the “best” session that is short-lived. One of my biggest values is sustainability. I’m not interested in anything that isn’t sustainable. If I can’t do it indefinitely, I’m not interested in it.

The best VO2max sessions are the ones you enjoy doing. The best Vo2max sessions are the ones you can repeat forever.

Ready to Boost Your VO2max?

If you enjoyed this and you want to see these interval sessions in practice, then try my structured training plans. My plans are based on science and results-proven practice. You can start with the plans below that comprise the best interval sessions to boost your VO2max. Enjoy!

  1. The Block Periodization Plan, 4 Weeks (6-8 Hours), 19.95$
  2. The Block Periodization Plan 2.0, 12 Weeks (6-8 Hours), 49.95$
  3. The Polarized Training Plan, 8 Weeks (6 Hours), 39.95$
  4. The Polarized Training Plan, 8 Weeks (10 Hours), 39.95$
  5. RV Improve Your FTP, 8 Weeks (10 Hours), 39.95$
  6. RV Gravel Advanced Base Plan 8-12 Hours (12 Weeks) – All Gravel Races, 119.00$

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Dr. Veronique Louise Billat:

Billat intervals: the magic bullet for your next PB?

Interval training at VO2max: effects on aerobic performance and overtraining markers:

Optimizing Interval Training Through Power-Output Variation Within the Work Intervals

Increasing Oxygen Uptake in Cross-Country Skiers by Speed Variation in Work Intervals.

Adaptations to aerobic interval training: interactive effects of exercise intensity and total work duration

Effects of Intensity and Duration in Aerobic High-Intensity Interval Training in Highly Trained Junior Cross-Country Skiers

Increasing Oxygen Uptake in Well-Trained Cross-Country Skiers During Work Intervals With a Fast Start

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