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The Number You Should Know & How to Improve It

/ VO2 Max Test / By

Top Line

Despite VO2max testing being considered the gold standard measurement of cardiorespiratory fitness and one of the strongest independent predictors of mortality, it is sadly seldom performed outside of the hospital cardiopulmonary ward. 

 

Why It Matters 

Care to live longer? Poor cardiorespiratory fitness, a low VO2max, is associated with an increased risk for chronic illnesses, such as obesity, diabetes, hypertension, and cardiovascular disease. Furthermore, from an athletic standpoint, VO2max is the best predictor of endurance performance.

 

Key Takeaways

  • VO2max is your body's ability to metabolize oxygen and is one of the best predictors of all cause mortality.
  • Data collected from testing can be used to customize your training and enhance performance.
  • Knowing your VO2max allows you to create a customized training plan to improve it. 

 

It's only human nature to benchmark. Athlete or not, knowing your numbers such as your one rep max (1RM) or body fat percentage can be a great way to set goals, track progress, and inform practice -- but perhaps the most boast-worthy, yet underappreciated, of these benchmarks is VO2max.

VO2max is the gold standard metric of the body’s ability to deliver and use oxygen (aerobic fitness) to produce energy for muscle contraction.

Obtaining this vital metric involves a maximum effort test typically performed on a treadmill. The body's responses to increasing workloads is measured throughout the test by monitoring changes in heart rate and gas exchange (breathing volume and rate). 

 

Why Have I Never Been Tested?

VO2max testing requires exercise laboratories equipped with both specialized equipment and personnel (Exercise Physiologists). If you grew up playing high school sports you are likely more familiar with the Pacer or “Beep” test as an estimate of aerobic capacity.

The Science

Knowing your VO2 max in a nutshell tells you how aerobically ‘fit’ you really are. 

Oxygen consumption (VO2) is equal to cardiac output (the product of heart rate and the volume of blood ejected per heartbeat) multiplied by the difference in arterial (oxygenated) and venous (deoxygenated) blood oxygen concentrations.

As the intensity of exercise increases, the cardiac output will also increase, resulting in an increase in the extraction of oxygen from the blood by the working muscles. To meet this increased oxygen demand we increase our consumption (VO2). Now at some point you will reach your maximum heart rate, consequently achieving your maximal cardiac output. At this point your VO2 will plateau even with increasing work rate. 

The value recorded for your VO2 max is this highest rate of oxygen consumption measured during the test -- when you’re working your hardest. 

VO2 max testing also provides perhaps the most important determinant of potential for endurance work, Anaerobic Threshold (AT) -- the highest  VO2 that can be sustained without lactic acidosis (symptoms of which include muscle pain and feelings of discomfort). We can use this to tailor training zones in relation to pace, heart rate and perceived exertion as well as inform your practice e.g. race day paces, power outputs or heart rate targets.

Can I Improve my VO2max?

Yes. 

Cardiovascular and muscular adaptations will lead to significant improvements in VO2max. (2, 11, 17, 19)

Endurance training can evoke a plethora of physiological adaptations leading to an increased metabolic efficiency of the aerobic energy system, including:

  • increased oxidative enzyme capacity - enhanced aerobic capacity (5, 6, 18)
  • increased mitochondrial density - enhanced aerobic capacity (12)
  • increased muscle capillarization - enhanced exchange rate (4, 14, 17)
  • increased fat utilization - better at running fat through the system (8)
  • decreased lactate and H+ accumulation - sustain a higher work rate for longer (9, 13, 15)
  • increased ability to store muscle glycogen - larger fuel tank (10)

The main goal of aerobic training programs is to elicit key adaptations with the intent to increase VO2max. (21) Response to training however will differ due to individuals’ differences such as training status, gender or genetics. In addition to this how you train -- how you manipulate variables such as intensity and duration -- will also influence physiological changes.

Traditional recommendations for improving VO2max include sustained, dynamic activity involving large muscle groups for a duration of 20 to 60 minutes for a minimum of three times per week at intensities above 50% VO2max.1 Common aerobic exercise modalities such as running and cycling at intensities greater than 60% VO2max have demonstrated significant increases in VO2max (e.g., 15 – 20%). (3)

Short on Time?

Reducing the duration but increasing the intensity has been demonstrated to be an alternative and effective way to enhance your VO2max. 

High intensity interval training (HIIT) can be a great way to improve your aerobic capacity as well as your ability to sustain a higher work rate for longer (delay lactic acidosis). Research comparing changes in VO2max between a moderate intensity endurance training and high intensity interval training suggest that short duration high intensity intervals can have the same effect on improving VO2max as the traditional and tedious moderate intensity long duration training.22 Improvements in endurance performance have been observed following low‐volume sprint interval training in as little as two weeks.20

Knowing your VO2max can give you an insight into your endurance performance as well as your health. Adaptations to endurance training will enhance your VO2max. 

For those of you who hate spending tedious hours on the bike or treadmill, the good news is you can keep your workouts interesting and time efficient -- while improving your overall health and physical fitness!

 

George Crouch, MSc

References

  1. American College of Sports Medicine (Ed.). (1991). Guidelines for Exercise Testing and Prescription. Williams & Wilkins.
  2. Blomqvist, C. G., & Saltin, B. (1983). Cardiovascular adaptations to physical training. Annual Review of Physiology, 45(1), 169-189.
  3. Cronan, T., & Howley, E. (1974). The effect of training on epinephrine and norepinephrine excretion. Medicine and Science in Sports, 6(2), 122-125.
  4. Denis, C., Chatard, J. C., Dormois, D., Linossier, M. T., Geyssant, A., & Lacour, J. R. (1986). Effects of endurance training on capillary supply of human skeletal muscle on two age groups (20 and 60 years). Journal de Physiologie, 81(5), 379-383.
  5. Gollnick, P. D., Armstrong, R. B., Saltin, B., Saubert 4th, C. W., Sembrowich, W. L., & Shepherd, R. E. (1973). Effect of training on enzyme activity and fiber composition of human skeletal muscle. Journal of Applied Physiology, 34(1), 107-111.
  6. Gollnick, P. D., & Saltin, B. (1982). Significance of skeletal muscle oxidative enzyme enhancement with endurance training. Clinical Physiology, 2(1), 1-12.
  7. Harber, M. P., Kaminsky, L. A., Arena, R., Blair, S. N., Franklin, B. A., Myers, J., & Ross, R. (2017). Impact of cardiorespiratory fitness on all-cause and disease-specific mortality: advances since 2009. Progress in Cardiovascular Diseases, 60(1), 11-20.
  8. Henriksson, J. (1977). Training induced adaptation of skeletal muscle and metabolism during submaximal exercise. The Journal of Physiology, 270(3), 661-675.
  9. Hickson, R. C., Hagberg, J. M., Ehsani, A. A., & Holloszy, J. O. (1981). Time course of the adaptive responses of aerobic power and heart rate to training. Medicine and Science in Sports and Exercise, 13(1), 17-20.
  10. Holloszy, J. O., & Booth, F. W. (1976). Biochemical adaptations to endurance exercise in muscle. Annual Review of Physiology, 38(1), 273-291.
  11. Holloszy, J. O., & Coyle, E. F. (1984). Adaptations of skeletal muscle to endurance exercise and their metabolic consequences. Journal of Applied Physiology, 56(4), 831-838.
  12. Howald, H. (1982). Training-induced morphological and functional changes in skeletal muscle. International Journal of Sports Medicine, 3(01), 1-12.
  13. Hurley, B. F., Hagberg, J. M., Allen, W. K., Seals, D. R., Young, J. C., Cuddihee, R. W., & Holloszy, J. O. (1984). Effect of training on blood lactate levels during submaximal exercise. Journal of Applied Physiology, 56(5), 1260-1264.
  14. Ingjer, F. (1979). Effects of endurance training on muscle fibre ATP‐ase activity, capillary supply and mitochondrial content in man. The Journal of Physiology, 294(1), 419-432.
  15. MacRae, H. S., Dennis, S. C., Bosch, A. N., & Noakes, T. D. (1992). Effects of training on lactate production and removal during progressive exercise in humans. Journal of Applied Physiology, 72(5), 1649-1656.
  16. Reuter, B. (2012). Developing Endurance. Human Kinetics.
  17. Saltin, B., & Gollnick, P. D. (1983). Handbook of Physiology. Skeletal Muscle.
  18. Saltin, B., Henriksson, J., Nygaard, E., Andersen, P., & Jansson, E. (1977). Fiber types and metabolic potentials of skeletal muscles in sedentary man and endurance runners. Annals of the New York Academy of Sciences, 301(1), 3-29.
  19. Saltin, B., & Rowell, L. B. (1980, April). Functional adaptations to physical activity and inactivity. In Federation Proceedings (Vol. 39, No. 5, pp. 1506-1513).
  20. Sloth, M., Sloth, D., Overgaard, K., & Dalgas, U. (2013). Effects of sprint interval training on VO 2max and aerobic exercise performance: a systematic review and meta‐analysis. Scandinavian Journal of Medicine & Science in Sports, 23(6), e341-e352.
  21. Snarr, R. L., D NSCA-CPT, P. C., & Tolusso, D. (2018). Understanding the Physiological Limiting Factors of VO2max.
  22. Tabata, I., Nishimura, K., Kouzaki, M., Hirai, Y., Ogita, F., Miyachi, M., & Yamamoto, K. (1996). Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max. Medicine & Science in Sports & Exercise, 28(10), 1327-1330.