Effect of Computational Method on Accumulated O2 Deficit

• Published in: Frontiers in sports and active living Vol. 4; p. 772049
• Main Authors: Medbø, Jon Ingulf, Welde, Boye
• Format: Journal Article
• Language: English
• Published: Frontiers Media 07.03.2022; Frontiers Media S.A
• Subjects: accumulated O2 deficit; anaerobic energy release; computation method; exercise economy; exercise efficiency; high-intensity exercise; Sports and Active Living
• ISSN: 2624-9367; 2624-9367
• DOI: 10.3389/fspor.2022.772049

The aim of this study was to examine how relationships between exercise intensity and the rate of energy release established in different ways, affect the calculated O 2 deficit accumulated during strenuous exercise. Aerobic energy release is readily measured by the O 2 uptake, while anaerobic energy release is by definition independent of O 2 . The latter is not easily measured during strenuous exercise, but it can be estimated using the accumulated O 2 deficit principle. We have calculated it using nine different approaches. Thirteen moderately trained persons (three women) volunteered to serve as subjects for cycle ergometry. Their maximal O 2 uptake was 2.9 ± 0.6 mmol s −1 ( x̄ ± s ; 3.9 ± 0.8 L STPD min −1 ). Our reference method (M0) is based on measuring the steady state O 2 uptake at the end of at least ten bouts of 10 min of exercise at constant intensity, varying between 30 and 40% of that corresponding to the maximal O 2 uptake and up to a power >90% of the maximal O 2 uptake, which is a rather time-consuming method. The outcomes of eight different simpler approaches have been compared with those of the reference method. The main result is that the accumulated O 2 deficit calculated depends a great deal on the relationship used to calculate it. A protocol of stepwise increases in exercise intensity every 4 min appeared to work well. A gross efficiency method showed the poorest performance. Another important result is that at constant power the O 2 uptake continued to increase beyond 4 min of exercise at all powers examined, also at powers well-below those corresponding to the lactate threshold. Finally, the O 2 uptake during loadless pedaling was considerably higher than resting O 2 uptake, and it appeared to follow a cubic function of the pedaling frequency. In conclusion, to obtain reliable values of the anaerobic energy release using the accumulated O 2 deficit principle, reliable relationships between exercise intensity and O 2 demand must be established.