What VO2 max is
VO2 max is the maximum amount of oxygen your body can take in and use during hard exercise. It is usually given as millilitres of oxygen per kilogram of body weight per minute. A higher number means your heart, lungs and muscles work together more effectively, so you can keep going at a harder pace for longer.
You do not have to be an athlete to care about it. Among health researchers, cardiorespiratory fitness is widely recognised as one of the best predictors of long-term health, and people with higher fitness tend to live longer and have lower risk of heart disease. Everyday benefits are simpler: stairs feel easier, you recover quickly, and you have more energy for work and family.
Genetics set a ceiling for each person, and age lowers it gradually. But most people are far below their ceiling, which means training can improve it noticeably, especially if you are starting from a low level.
How to get an idea of your level
A laboratory test with a mask is the gold standard, and it is rarely needed. For everyday purposes, track simple markers instead.
- How far you can walk or run in 12 minutes.
- How long it takes you to cover 1.5 km or 3 km.
- Your resting heart rate each morning, which tends to drop as fitness improves.
- How quickly your heart rate comes down after hard effort.
Smartwatches give a VO2 max estimate. Treat it as a rough trend line, not an exact figure. If the number rises over months, you are going in the right direction.
The 2 training types that move the needle
Improving VO2 max needs 2 ingredients: a large volume of easy aerobic work, and some hard intervals that push your heart to near its limit.
Easy aerobic base work
This is the foundation. Brisk walking, easy jogging, cycling or swimming at a pace where you can talk builds the heart's capacity and strengthens your muscles' ability to use oxygen. Aim for 3 or 4 sessions a week of 30 to 60 minutes. The WHO target of at least 150 minutes of moderate activity a week is a good minimum.
Hard intervals
Short hard efforts of 3 to 5 minutes, repeated with recovery, are particularly effective at raising VO2 max. They push your heart close to its maximum rate and teach it to deliver more blood per beat.
Sample interval sessions
Do 1 or 2 of these per week, never on consecutive days, and only after several weeks of base training.
4 by 4 minutes
- Warm up for 10 minutes at an easy pace.
- Run, cycle or row hard for 4 minutes at an effort of about 8 out of 10. You should be breathing heavily and only able to say a few words.
- Recover for 3 minutes of very easy movement.
- Repeat 4 times in total.
- Cool down for 5 to 10 minutes.
30 and 30s
Warm up well. Alternate 30 seconds fast with 30 seconds easy for 10 to 15 minutes. It feels more manageable for beginners.
Hill repeats
Find a steady slope. Run or walk hard uphill for 90 seconds, walk back down to recover, and repeat 6 to 8 times. Hills reduce the impact on your joints compared with fast flat running.
If you have a heart condition, high blood pressure, diabetes, chest pain or breathlessness that worries you, get medical advice before attempting hard intervals.
Build it into a week
A sensible week for someone who already walks or jogs regularly:
- Monday: Easy 40 minute run or brisk walk.
- Tuesday: Strength training.
- Wednesday: Interval session such as 4 by 4 minutes.
- Thursday: Rest or gentle walk.
- Friday: Strength training and 20 minutes easy cardio.
- Saturday: Long easy session, 60 minutes or more.
- Sunday: Rest.
Hard work should be about one fifth of your weekly cardio. The rest stays comfortable. Many people reverse this and make every session moderate-hard, which leads to plateaus and tiredness.
Strength training helps too
Stronger legs and a stronger core let you hold your pace for longer and reduce injury risk. 2 sessions a week with squats, lunges, deadlifts, step-ups and rows is plenty. You do not need heavy weights to start. Good technique and steady progress matter more.
Fuel, sleep and recovery
Hard training needs fuel. Carbohydrate foods such as rice, matooke, posho and sweet potato supply energy, while beans, fish, eggs, chicken and groundnuts provide protein for repair. Fruit and vegetables add vitamins and fibre. Iron deficiency is common and can reduce endurance, particularly in women. If you are always tired despite adequate training and sleep, ask your doctor about a blood test.
Sleep is when adaptation happens. Aim for 7 to 9 hours. If your resting heart rate is a few beats higher than normal and you feel heavy, take an easy day.
Common mistakes
Doing only moderate-hard work. Easy days should be easy. Hard days should be hard. The middle ground builds fatigue without strong results.
Starting intervals too early. Give your body at least a month or 2 of regular easy training initially.
Too many hard sessions. 2 a week is the upper limit for most people.
Expecting overnight changes. Meaningful gains usually appear over 6 to 12 weeks. Be patient, keep a training log, and repeat your 12 minute test every month or so.
Training in extreme heat. In hot, humid weather, performance drops and risk of heat illness rises. Train early or late in the day and reduce pace if needed.
Key takeaways
- VO2 max measures how well your body uses oxygen, and higher fitness is linked with better long-term health.
- Most people can improve it with consistent training, even if genetics set the upper limit.
- Combine plenty of easy aerobic sessions with 1 or 2 hard interval sessions per week.
- Intervals of about 4 minutes at a hard effort are especially effective once you have a base.
- Strength work, good food and sleep support progress.
- See a doctor before hard training if you have a heart condition, high blood pressure or other health concerns.
