Maximal oxygen uptake (V̇O2max) reflects the ability of the respiratory and circulatory systems to deliver oxygen to the muscles working during exercise, and the ability of those muscles to utilise oxygen for energy production. It indicates the overall condition of the heart, lungs, and muscles, and is considered the best single measure of cardiorespiratory fitness and a key indicator of overall health.

Precise measurement of maximal oxygen uptake is essential for monitoring exercise effects, assessing population fitness, and detecting health risks.

In adolescents, measuring maximal oxygen uptake is more difficult than it is in adults. For adults, oxygen consumption usually plateaus at the end of the test, indicating that maximal oxygen uptake has been reached. In adolescents, this often does not occur, even when the test is continued to the point of exhaustion. In such cases, it may remain unclear whether a true maximal oxygen uptake was measured.

This study explored whether a short, intense verification phase can confirm adolescents’ maximal oxygen uptake. It also assessed how different time averaging strategies for the data affect the final measurement results.

The verification phase confirmed maximal oxygen uptake in most adolescents. However, four adolescents achieved a clearly higher oxygen uptake during the verification phase, indicating that their initial result would have otherwise underestimated their cardiorespiratory fitness.

“Our results highlight that adolescents’ maximal oxygen uptake should be confirmed with a separate verification phase,” says Petri Jalanko, doctoral researcher at the University of Jyväskylä and exercise physiologist at the Helsinki Clinic for Sports and Exercise Medicine.

The researchers also observed that the time averaging strategy used for the measurement data affected adolescents’ maximal oxygen uptake values. On average, the differences were small, but in some cases, they were surprisingly large.

“In one adolescent,” Jalanko says, “maximal oxygen uptake appeared almost seven per cent higher solely because the data was averaged differently.”

“This indicates that the choice of time averaging strategy can affect the evaluation of an adolescent’s cardiorespiratory fitness. Hence, it is crucial to explicitly specify the time averaging strategy used.”

The study provides new information on how to measure adolescents’ cardiorespiratory fitness as reliably as possible. Jalanko emphasises, however, that further research is still needed on this topic, including the use of different test methods, such as running tests.

The results come from the Vascular and Brain Health, Exercise, and Nutrition in Adolescents (VERNA) study, led by Research Director and Adjunct Professor Eero Haapala at the Institute of Biomedicine, University of Eastern Finland. A total of 27 adolescents from Jyväskylä, Finland, aged 12–14 years, took part in the study, including 17 girls. Maximal oxygen uptake was measured using an incremental cycle ergometer ramp test to exhaustion. The verification phase was performed after 15 minutes of recovery at 105% of the work rate achieved in the first test. Maximal oxygen uptake was analysed using 15-second binned and moving averages. The results were published in the respected European Journal of Applied Physiology.