VO2max stands for volume, oxygen, maximum—it’s the max rate of oxygen consumption measured during exercise. It is the key measure of cardio fitness. The higher your VO2max, the fitter and healthier you are.
In this guide, we’ll explore the best ways to increase VO2max and answer key questions like how long does it take to improve VO2max?
Why is VO2max important?
When exercising, there are 2 main energy systems that your body can use—aerobic and anaerobic. The aerobic system is fueled by oxygen and can sustain activity for hours, while the anaerobic system provides short bursts of energy but fatigues quickly.
Any training that lasts more than a few minutes is an aerobic activity, during which the oxygen your muscles receive from your cardiovascular system becomes the main fuel. If your muscles don’t receive enough oxygen, your body switches to an anaerobic energy system and can no longer sustain the same level of effort for longer periods.
This means that if you want to increase the length of your training and improve your performance, the maximal oxygen uptake (VO2max) is the metric you should start tracking.
In addition to boosting performance, research shows that high VO2max can increase longevity along with additional health benefits. In fact, improving your VO2max by just 12% is like turning your body clock back 10 years.
How to measure VO2max
Your VO2max is a measure of how fit you are, and it depends on a number of factors including age, gender, and fitness level.
To get an accurate measure of your VO2max, you’ll need a lab test involving a treadmill or stationary bike, where your oxygen consumption and carbon dioxide production are monitored.
While there’s no way to track it outside the lab accurately, at-home fitness tools like the CAROL Bike now provide practical ways to track your progress over time, offering fitness tests and personalized metrics for VO2max improvement.

Accurately tack your VO2max with CAROL Bike's built-in fitness trackers.
How long does it take to increase VO2max?
Your VO2max improves when your heart muscle becomes stronger and can deliver larger amounts of oxygenated blood to your muscles with every heartbeat. The time it takes to improve your VO2max depends on your starting fitness level. Beginners often see improvements within 4–6 weeks of consistent training.
A BMC Genomics study showed that VO2max is 50% influenced by our genetics. Elite athletes often hit their physiological and genetic limits, making it very hard for them to progress further. Regardless of your efforts, VO2max declines by about 10% every decade after the age of 30.
Here are 7 actionable steps to improve your VO2max:
1. High-intensity interval training
HIIT involves alternating short bursts of intense exercise with rest or low-intensity recovery periods. A PubMed Central study found that interval workouts improve VO2max faster than continuous aerobic exercise. Interval training consists of alternating short periods of high-intensity exercise with periods of rest that better train your heart muscle. Although there are many different types of interval training, high-intensity interval training (HIIT) is one of the most efficient approaches to increase VO2max. With HIIT, you work out at 90–95% of your max heart rate capacity during short periods. For example:
- Perform 30-second sprints followed by 1–2 minutes of light jogging.
- Repeat for 15–20 minutes.
Training at the limit of your capacity strengthens your heart muscle and increases blood oxygen delivery, contributing to a better result.
2. Reduced exertion HIIT
Reduced exertion HIIT (REHIT) is the next-level HIIT workout—it gives you double the health benefits compared to regular exercise in just 10% of the time. REHIT is the most effective way to improve your cardiovascular fitness—you can increase your VO2max by 12% in just 8 weeks. CAROL Bike is the only home REHIT exercise bike, with AI-personalization and Instant Resistance. Offering the shortest, most effective workouts, CAROL Bike lets you pack a 45-minute cycling session into just 5 minutes.

REHIT is the most effective way to improve your cardiovascular fitness.

CAROL Bike can increase your VO2max by 12% in just 8 weeks.
3. Diversify your training
Although the HIIT and REHIT protocols show the most efficient results in terms of improving your aerobic fitness, it is important to include other types of training in your workout routine as well. In order to improve VO2max, it’s important to exercise regularly. Some studies found that the greatest VO2max increase happened during a program of 6 workouts per week.
It’s recommended to incorporate 2–3 REHIT sessions per week, while on other days you can focus on strength and long endurance training.
Research published in the European Review of Aging and Physical Activity finds a direct correlation between resistance training and an increase in VO2max in young and older subjects alike.
4. Challenge yourself with fitness goals
As we already mentioned, the easiest way to keep track of your VO2max outside of the lab is to measure the time and pace of your training.
Tracking your performance is key to progression. Use metrics like:
Running pace: Try running at 95% of your maximum capacity. Discover how fast you can run 5 kilometers and use this pace as a target metric for training at your maximum oxygen consumption level.
Cycling power: Use Functional Threshold Power (FTP) to guide your intensity during cycling workouts. You can find your FTP by performing a test on a bike with a power meter. After your warm-up, ride as hard as you can for 20 minutes and then subtract 5% from this power score to get your FTP result.
CAROL Bike’s AI technology personalizes your workouts for you, so you can hit your maximum intensity every time. It also offers a range of fitness tests for calculating your FTP.
5. Give yourself time to recover
Progress happens during recovery, not just during workouts. Overtraining can stall improvements in VO2max and increase the risk of injury. After a relatively light workout, your muscles may be able to recover in 24 hours, but it can take up to 72 hours for more challenging workouts. Taking regular rest days is a critical part of your progress.
The good news is that research from a PubMed study that the higher your VO2max gets, the less time you need for a proper recovery. Your sleep quality is an important part of rest, too. A good night’s sleep is the base of your performance, so aim for at least 7–8 hours per night. You can improve the quality of your sleep by sticking to the best practices in your sleeping routine: go to bed around the same time every night and wake up around the same time every morning, stop using screens 30 minutes before bedtime, and avoid caffeinated beverages after midday.

Don't forget: taking regular rest days is a critical part of your progress.
6. Get rid of excess body weight
The negative correlation between VO2max and body weight is confirmed by multiple studies: the more extra weight participants had, the lower their VO2max. Getting rid of extra weight will increase your body’s ability to perform endurance exercise and achieve better results.
Although regular training contributes to keeping you in shape, it is not enough on its own. To lose weight, you will need to focus on a holistic approach to weight loss.
7. Switch to a healthier lifestyle
Sustainable improvements to VO2max require long-term lifestyle changes. Stay hydrated, and incorporate meals that exclude sugar, simple carbs, and trans fats while eating more fruits and vegetables, lean protein, whole grains, and low-fat dairy.
Some research has found that a high-fat diet is the most efficient type of diet to increase VO2max, so you may consider adding more unsaturated fats from olive oil, nuts, and avocado to your meals.
Supplements that can help you improve your VO2max faster are omega-3, beetroot powder, iron, and beta-alanine.
The bottom line
VO2max is the gold standard for measuring your maximum aerobic capacity. It has a great effect not only on your endurance and performance but also on your cardiovascular health. The best way to increase VO2max is to exercise near your maximum heart rate, and the easiest way to do this is with CAROL Bike’s signature REHIT workouts.

Got a question? Let's book a call.
All our experts have MSCs in Exercise Science, and they’re here to answer your questions. Whether it’s about the science behind CAROL Bike, or general fitness advice, whatever’s on your mind—we’re here for you.