Integrating VO2 Max Intervals for Sustained Endurance Gains

Improving your endurance on the bike isn’t just about riding more miles. It’s about training smarter (although not necessarily harder). One great way to improve your aerobic endurance is through interval training, which improves your VO2 max. Let’s take a look at everything you need to know about this type of training, along with practical interval training you can start incorporating into your plan today.

What is VO2 Max?

Put simply, VO2 max is the maximum amount of oxygen your body can consume during exercise. The V stands for volume, O2 is oxygen, and max is maximum. Your heart pumps oxygen-rich blood to your muscles, which then use that oxygen to produce power. The better this system works, the higher your VO2 max, and the more power you’ll be able to produce – meaning faster times and better endurance. 

VO2 max is often thought to be the defining factor when it comes to measuring how good an athlete’s cardiovascular fitness and aerobic endurance are. And the good news? It’s possible to train your VO2 max.

“VO2 max is a very important data point for a cyclist. I mainly focus on VO2 max training at the start of the season (October and November for the following spring and summer) to build a strong engine. After that, I focus on other areas to optimize my performance for the goals of the season.”

 Christian O. - Cyclist and Supply Chain Lead at GOREWEAR 

Why Is VO2 Max Important When it Comes to Cycling?

Your VO2 max is, essentially, the size of your aerobic engine. The higher your VO2 max, the more power you can sustain for longer. When you’re riding aerobically, your body can efficiently use oxygen to fuel your muscles, without making you feel too fatigued. But if you exceed your aerobic capacity, it means that your body will switch to the anaerobic energy system, which is less efficient and you’ll end up fatigued.

If you have a high VO2 max, you’ll be able to:

• Sustain harder efforts for longer periods without that burning sensation in your legs that can force you to dial the effort back.

• Improve your threshold power. Whether you call it FTP, lactate threshold or critical power, a higher VO2 will ensure it’s higher as you’re able to process more oxygen.

• Recover faster between hard efforts. When you go hard, your muscles produce lactate and other byproducts that can contribute to fatigue. A higher VO2 can help you to clear these byproducts faster, so you can bounce back more easily.

And these benefits can be felt across all cycling disciplines, whether you’re a sprinter, a mountain biker, or an endurance rider. If you’re looking to improve your performance to go faster or longer, VO2 max intervals for cycling could be the key.

The Science Behind VO2 Max Intervals

VO2 max intervals are high-intensity training sessions that are designed to push your aerobic capacity to its maximum. These workouts usually involve repeated efforts at a pace that’s at or above your functional threshold power (FTP), with short recovery periods in between. You should be aiming to ride at around 90-100% of your maximum heart rate for each of the intervals.

The idea is that by spending time at – or very close to – your limits, it’ll force adaptations to improve your aerobic capacity. A 2024 study on well-trained cyclists found that the more time the riders spent above 90% of their VO2 max during interval training, the greater their gains in aerobic fitness and power output. The cyclists who hit a higher percentage of their VO2 max saw an increase in their maximum aerobic power, an increase in their power at lactate threshold, and huge overall performance gains.

And VO2 max intervals aren't just for elite athletes. One study found that untrained men who incorporated short blocks of 10-20-30 method (10 seconds of high intensity, 20 seconds at moderate pace, and 30 seconds easy) into their training for six weeks improved their VO2 max by 8%. While 10-20-30 intervals are much shorter than the typical VO2 max intervals, it shows that even minimal high intensity training can result in improvements to your aerobic capacity.

How To Improve VO2 Max

If you want to improve your endurance on the bike, try incorporating VO2 max intervals into your training plan once or twice a week, spacing sessions ideally by a couple of days to allow for proper recovery.  

And VO2 max intervals don’t need to be complicated, even if you’re new to this type of workout. Here are some simple sessions to try:

Rønnestad intervals 

These are a type of high intensity interval training (HIIT) workout, popularised by Bent Rønnestad, a renowned sports scientist. They alternate between 30 seconds at high intensity and 15 seconds of recovery where you continue to pedal slowly. Do 3 sets of 13 repetitions, with 3 minutes of recovery between sets.

Seiler 4x8 intervals

These are named for Dr Stephen Seiler, who found that greater improvements to VO2 max were found with longer, slightly lower intensity sessions (at 90% of max heart rate) compared to shorter, harder sessions (at 95% max heart rate). Do 8 minutes of hard riding at 90% of your maximum heart rate with 3 minutes of active recovery between intervals. Repeat 4 times.

Billat intervals

These are developed by exercise physiologist Véronique Billat which focus on vVO2 max. The extra ‘v’ stands for velocity and it’s a measure of the lowest intensity at which your body reaches its maximum oxygen uptake. Billat intervals, then, use this level of power in short bursts to help you spend more overall time at your VO2 max without getting tired. Alternate between 30 seconds at vVO2 max and 30 second easy recoveries – and repeat for as long as possible, until you can’t possibly do any more.

VO2 max intervals are likely to feel hard – after all, you’re working at your absolute limit, even if only for short bursts at a time. But as you adapt to the training, you’ll probably find that you need to do longer or harder intervals over time. But there’s no need to rush into doing harder and harder sessions every week. The progression should be gradual, and always balanced with plenty of rest and recovery to make sure you see the benefits.

It can take as little as a few weeks to see improvements to your VO2 max. Most smartwatches track your VO2 max, so it’s easy to see progress over time. If you don’t see an improvement, it may be down to several factors. These include  not allowing enough recovery between sessions, training at high intensity too frequently, insufficient sleep, or simply needing more time if you're already well-trained. You could also simply have reached your genetic limit. VO2 max can be improved through training, but everyone has different limits.

Overall, when it comes to doing VO2 max intervals, the aim isn’t to destroy yourself so you can’t ride again for days. The idea is to challenge your aerobic system with short bursts of high intensity training. Over time, you’ll see the gains when it comes to your endurance, helping you to ride harder for longer, whatever type of cycling you prefer.