How can I train my VO2max?

In connection with endurance training, there is a lot of talk about the so-called VO2max. But what is it exactly and what physiological effects does VO2max have on the athlete? We would like to answer these questions here. 

Definition VO2max

What does maximal oxygen uptake (VO2max) mean?
The maximum oxygen uptake represents the amount (V) of oxygen (O2) that a person can take in at maximum (max) at sea level. It is the standard measure of aerobic performance and is commonly abbreviated as VO2max. VO2max describes the oxygen uptake capacity of the working muscles per minute and their resulting energy supply (1). VO2max is measured through a respiratory gas analysis during a sport-specific workout on a bicycle ergometer or treadmill (8).

Which physiological factors influence the maximum oxygen uptake?
The maximum oxygen uptake is the product of cardiac output (HMV) and the arterial-venous oxygen deficit. The cardiac output describes the work done by the heart per minute and is in turn composed of heart rate (HR; beats per minute) and stroke volume (SV) (6). 
The stroke volume describes the amount of blood pumped through the heart per heartbeat. In endurance-trained persons, the size of the heart adapts to the training (athlete's heart) and can consequently transport a larger amount of blood per heartbeat. This often results in a larger cardiac output in athletes (6). 
The arterial-venous oxygen deficit shows the difference in oxygen content in the arteries and the veins. The arteries transport the oxygen-rich blood to the muscle cells, whereas the veins transport the oxygen-poor blood back to the lungs. Here, the oxygen-poor blood is re-oxygenated through respiration. Under exertion, the arterial-venous oxygen deficit becomes more pronounced, as the muscles consume more oxygen during increased activity and thus there is less oxygen in the veins.
This results in a high maximum oxygen uptake when there is a high cardiac output (HR x SV) and a high arterial-venous oxygen deficit.

VO2max normal values (6, 7) (6, 7)

Absolute VO2max values:
Non-endurance trained healthy individuals: 3 - 3.5 l/min.
Endurance trained persons: 5 - 6 l/min

Relative VO2max values:
Endurance-trained persons: 80 - 90 ml/min/kg 
Non-endurance trained healthy persons: 35 - 50 ml/min/kg
The maximum oxygen uptake in women is about 10 - 15% lower than in men.

Significance of VO2max

How can I compare the VO2max?
The value of the absolute maximum oxygen uptake is given in liters of oxygen per minute (l/min). However, this is insufficient for an individual comparison of endurance performance between individuals. The reason for this lies in the different anthropometric data (body height, body weight) of the individual athletes.

Example:
If a 60 kg and a 50 kg female cyclist with a VO2max of 5 l/min race against each other, it can be assumed that the 60 kg female cyclist has to expend more energy and thus more oxygen to move her body. Consequently, it can be assumed that the lighter athlete with the 5 l/min can maintain the race speed longer than her competitor. 
"An exclusive increase in body weight thus leads to a decrease in weight-related VO2max" (Meyer & Kindermann, 1999, p. 285).
To make this value comparable, the maximum oxygen uptake is normalized to body weight. This is a relative maximum oxygen uptake expressed in milliliters per minute per kilogram (ml/min/kg). 

Adjusting VO2max 

How can I train my VO2max?
To increase VO2max, it is important to maintain a good balance of intense and restorative training. It is recommended to train bipolar. This corresponds to a ratio of ~80% regenerative and ~20% intensive training (11). Studies have significantly shown that maximal oxygen uptake is best increased when training in high intensity zones such as HIT_EB and HIT_IE (3, 4, 5, 9, 12).
Within the HIT_EB or HIT_IE intensity zones, the athlete is in the range of > 88% of VO2max (3). This means that the cardiovascular system has to transport a particularly large amount of oxygen to the muscles and thus works close to the maximum intake capacity. Consequently, during the intervals, care should be taken to exploit the full time within the high intensity.
Nevertheless, as the above-mentioned bipolar training suggests, quality rather than quantity applies here.

Sources:

1. Basset, D.R. & Howley, E. T. (2000). Limiting factors for maximum oxygen uptake and determinants of endurance performance. Med Sci Sports Exerc 32: 70–84.
2. Faude, O., Meyer, T., Scharhag et al. (2008). Volume vs. intensity in the training of competitive swimmers. International Journal of Sports Medicine. 29(11): 906-912.
3. Fiskerstrand A, Seiler KS. Training and performance characteristics among Norwegian international rowers 1970-2001. Scand J Med Sci Sports. 2004;14:303–310.
4. Gormley, S., Swain, D., High, R., et al. (2008). Effect of intensity of aerobic training on V̇O2max. Medicine and Science in Sports and Exercise, 40(7): 1336-1343.
5. Gutin, B., Barbeau, P., Owens, S., Lemmon, C. R., Bauman, M., Allison, J., … & Litaker, M. S. (2002). Effects of exercise intensity on cardiovascular fitness, total body composition, and visceral adiposity of obese adolescents. The American journal of clinical nutrition, 75(5): 818-826.
6. Kramme, R (2016). Organprofile und Normwerte BT  – Medizintechnik: Verfahren – Systeme – Informationsverarbeitung. 1-28.
7. Meyer, T. & Kindermann, W. (1999). Die maximale Sauerstoffaufnahme (VO₂max). Deutsche Zeitschrift für Sportmedizin, 50(9): 285-286. 
8. Meyer, F., Borst M., Buschmann, H. et al., (2018). Belastungsuntersuchungen in der Pneumologie – Empfehlungen der Deutschen Gesellschaft für Pneumologie und Beatmungsmedizin e. V.. Journal of Pneumologie. 687-731.
9. O’Donovan, G., Owen, A., Bird, S. R., Kearney, E. M., Nevill, A. M., Jones, D. W., & Woolf-May, K. (2005). Changes in cardiorespiratory fitness and coronary heart disease risk factors following 24 wk of moderate-or high-intensity exercise of equal energy cost. Journal of applied physiology, 98(5): 1619-1625.
10. Péronnet, F. & Thibault, G. (1987). Physiological analysis of running performance. Revision of the hyperbolic model. Journal of Physiology, 82(1): 52-60.
11. Seiler, S. (2010). What is best practice for training intensity and duration distribution in endurance athletes? International Journal of Sports Physiology and Performance. 5(3): 276-291
12. Swain, D. P. & Franklin, B. A. (2006). Comparison of cardioprotective benefits of vigorous versus moderate intensity aerobic exercise. Am J Car- diol. 2006; 97:141–7.