Impact of data averaging strategies on V̇O_2max assessment: Mathematical modeling and reliability

Abstract

Background No consensus exists on how to average data to optimize trueV˙O2max assessment. Although the trueV˙O2max value is reduced with larger averaging blocks, no mathematical procedure is available to account for the effect of the length of the averaging block on trueV˙O2max. Aims To determine the effect that the number of breaths or seconds included in the averaging block has on the trueV˙O2max value and its reproducibility and to develop correction equations to standardize trueV˙O2max values obtained with different averaging strategies. Methods Eighty‐four subjects performed duplicate incremental tests to exhaustion (IE) in the cycle ergometer and/or treadmill using two metabolic carts (Vyntus and Vmax N29). Rolling breath averages and fixed time averages were calculated from breath‐by‐breath data from 6 to 60 breaths or seconds. Results trueV˙O2max decayed from 6 to 60 breath averages by 10% in low fit (trueV˙O2max < 40 mL kg−1 min−1) and 6.7% in trained subjects. The trueV˙O2max averaged from a similar number of breaths or seconds was highly concordant (CCC > 0.97). There was a linear‐log relationship between the number of breaths or seconds in the averaging block and trueV˙O2max (R2 > 0.99, P < 0.001), and specific equations were developed to standardize trueV˙O2max values to a fixed number of breaths or seconds. Reproducibility was higher in trained than low‐fit subjects and not influenced by the averaging strategy, exercise mode, maximal respiratory rate, or IE protocol. Conclusions The trueV˙O2max decreases following a linear‐log function with the number of breaths or seconds included in the averaging block and can be corrected with specific equations as those developed here.

Regulation of Nrf2/Keap1 signalling in human skeletal muscle during exercise to exhaustion in normoxia, severe acute hypoxia and post-exercise ischaemia: Influence of metabolite accumulation and oxygenation

“…The validity of the metabolic cart was established by a butane combustion test [ 43 ] and cross-checking end-tidal CO 2 pressures with arterial blood CO 2 partial pressures (ABL90, Radiometer, Copenhagen, Denmark) [ 44 ]. Respiratory variables were averaged every 20 s for O 2 peak assessment [ 45 ].…”

Sarcolipin expression in human skeletal muscle: Influence of energy balance and exercise

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Resting Energy Expenditure and Body Composition in Overweight Men and Women Living in a Temperate Climate

“…The final sample was similar in size to that of Johnstone et al [32] who also determined body composition by DXA, and developed an equation that performed very well in our male population. We used two different metabolic carts during the study, but both were verified with a butane combustion test and cross-calibrated, as previously reported [43,66]. The observations made in this investigation are specific to our Caucasian populations and cannot be generalized to other ethnic groups.…”