Running at the best of your ability can be a bit of a numbers game. To hit new PBs, you may want to keep tabs on a range of statistics, like distance covered, average pace, average heart rate, hours slept… We could go on.

But at the end of the day, it’s this one measurement that arguably has the most bearing on your performance: VO2 max. ‘VO2 max is a measure of the amount of oxygen that your body can use,’ says Juli Benson, Olympian and owner of Juli Benson Training. It’s a number that denotes what volume of oxygen – in millilitres per kilogram of body weight per minute – that your body delivers during activity. Simply put, it’s a gauge of your aerobic capacity.

Here’s how to measure and improve your VO2 max for faster running and greater overall health.

How to measure your VO2 max

There are a few ways to determine your VO2 max score. The first – and most accurate – is to have it tested in a performance lab. But that’s also pricey and uncomfortable, as you’ll have to endure a tough session at an all-out effort on a treadmill with a mask strapped to your face.

Another option is to wear a smartwatch that offers VO2 max estimates. Some Garmin watches, for example, approximate your score based on your heart rate and running pace data.

You can also roughly calculate your VO2 max using a simple equation, based on your maximum heart rate (MHR) and resting heart rate (RHR): VO2 max = 15 x (MHR/RHR). But for a little more accuracy, you can also perform at-home tests, including the Cooper Test or the Rockport Walk Test.

5 workouts to boost your VO2 max

Your genes play a huge role in determining your VO2 max, which, of course, is something that you can’t control. However, Benson says that it is still possible to improve your VO2 max ‘with good old-fashioned hard work’.

Getting faster by way of VO2 max work is all about efficiency. ‘The higher your VO2 max, the faster or more efficiently you’ll be able to finish a race or training run, as your body moves the oxygen in the most effective manner,’ says April Gatlin, ACE-certified personal trainer and vice president of education at STRIDE Fitness.

The best way to train your body to do just that is by regularly tackling intervals – both interval runs and HIIT sessions incorporating strength moves. The good news is that while you need to do intervals regularly, it shouldn’t take long before you see gains. ‘If you’re consistent in training to increase VO2 max, people should start to notice a difference in approximately six weeks,’ says Gatlin. (This is particularly true for those who are newer to running – it may take longer for those who are already fit.)

Research backs this up. According to a 2018 study published in the Journal of Strength and Conditioning Research, runners who did 200m interval workouts for only 10 weeks improved their aerobic capacity and VO2 max significantly more than runners who stuck to moderately-paced workouts. Similarly, as per a 2019 meta-analysis of studies published in the Journal of Science and Medicine in Sport, people who did HIIT sessions with intervals as short as 30 seconds for four weeks or less showed VO2 max improvements, while participants who did intervals closer to two minutes for four to 12 weeks showed even greater gains.

5 workouts to challenge your VO2 max

The best way to improve your VO2 max is to tap into the right heart rate zone during those intervals. ‘In general, VO2 max work should be completed at about 90-100% of your maximum heart rate,’ says Benson. That’s about the same as your 5K pace and each of the five workouts detailed – as recommended by Benson and Gatlin – include intervals at that approximate intensity. Feel free to dial it back a bit, says Benson, if you’re new to this type of training.

Before each of these sessions, warm up by jogging for eight to 15 minutes, then do some dynamic stretches or range of motion drills, like high knees and leg swings, followed by a few reps of 20-second strides to prepare your body to pick up the pace.

The tough interval sections of the workouts can range from about 10 minutes for novices to 25 minutes for advanced runners – pick your reps below to match your current fitness level. It’s always smart to start on the lower end, see how it feels, then work your way up to more reps.

Benson suggests that newbies should do two VO2 max workouts a month, while more experienced runners should do up to one a week. For the biggest benefit, try not to schedule them the day after a long run or other challenging session. ‘These types of workout sessions should be done during the week and sandwiched between two very easy days of running, cross-training or rest days,’ says Benson.

1. 1000m repeats

Run 1000m at a 5K effort, then walk or jog for the same amount of time that it took to complete the run. Repeat this three to six times.

2. Two by twos

Run for two minutes at a 5K effort, then walk or slowly jog for two minutes. Repeat this four to eight times.

3. Ladder

Run for two minutes and 30 seconds at your 10K effort, then rest for the same amount of time. Run for three minutes and 30 seconds at your 10K effort, then rest for the same amount of time. Run for four minutes and 30 seconds at your 10K effort, then rest for the same amount of time. Then, repeat the entire set of intervals at your 5K effort.

4. Bodyweight AMRAP

Do 10 push-ups followed immediately by 10 bodyweight squats, then run 400m at your 5K or 10K pace. Repeat as many reps as possible for 20 minutes, resting when needed.

5. EMOM sprints

Sprint at a pace that you can sustain for 10 to 15 seconds, then jog for the remainder of the minute. Repeat for 20 minutes. Work up to sprinting for 20 or 30 seconds each minute.