Effect of sampling strategy on measures of V?O2peak obtained using commercial breath-by-breath systems

Abstract

The purpose of this study was to determine the effect of sampling strategy (i.e., number of breaths) on measured peak rate of oxygen uptake ( VO(2peak)) elicited by a range of severe intensity exercise bouts. The hypothesis was that a smaller sample (i.e., fewer breaths) would produce a higher measure of VO(2peak) and that this effect would be greater in shorter tests than in longer tests. Thirty-three university students performed constant-power cycle ergometer tests at intensities selected to elicit fatigue in ~3.0 min (short duration), approximately 5.5 min (medium duration), and approximately 8.0 min (long duration). Values for VO(2peak) were the highest rates of oxygen uptake obtained using the following sampling methods: single breath, and 3-, 5-, 15- and 30-breath rolling averages. As hypothesized, measures of VO(2peak) increased systematically with decreasing sample size. Contrary to the hypothesis, the effect of sample size was greater in medium duration and long duration tests than in the short duration tests. The interaction between test duration and sample size on measures of VO(2peak) highlights the importance of standardizing the analysis protocol for exercise in the severe domain. If such standardization is not feasible, it should be recognized that specific analysis protocols may exert a substantial effect upon the reported VO(2peak).

Effect of the o2 time‐averaging interval on the reproducibility of o2max in healthy athletic subjects

“…, 1990) and should increase the reproducibility of o 2max . In support of this hypothesis, among young healthy subjects the within‐subject coefficient of variation (range 6–9%) for O 2peak during repeated exercise bouts performed on separate days, tended to be lower for larger rolling breath averaging intervals (Hill et al. , 2003).…”

Reproducibility of incremental maximal cycle ergometer tests in healthy recreationally active subjects

“…In line with our hypothesis, the VO 2 peak values did increase as the time‐averaging interval became shorter. This observation is consistent with previous findings (Johnson et al ., ; Hill et al ., ; Midgley et al ., ). Moreover, the shorter time‐averaging intervals may not sufficiently reduce the false measurements (random errors) in the breath‐by‐breath VO 2 data and thereby give rise to artificially high VO 2 peak values, whereas the longer interval (60 s) may artificially depress the true VO 2 peak, due to loss of information, during incremental exercise testing (Roecker et al ., ; Midgley et al ., ).…”

Respiratory gas exchange and physiological demands during a fire fighter evaluation circuit in men and women

“…Following 4 min of warm up at a light running speed, the velocity increased to a comfortable running pace and the grade increased two percent every 2 min thereafter. The test was terminated when the subjects were unable to continue in spite of encouragement and VO 2 max was taken as the average of the highest Wve consecutive breaths attained in the last minute of exercise; a technique that would yield the highest possible value (Hill et al 2003). Ventilatory threshold (T vent ) was determined from the point of increased minute ventilation (V E ) to VO 2 ratio without a marked increase in V E to CO 2 output (VCO 2 ) ratio.…”