Calculation of oxygen uptake efficiency slope based on heart rate reserve end-points in healthy elderly subjects

Abstract

We tested the validity of an new methodological approach to the calculation of oxygen uptake efficiency slope (OUES) [i.e. the use of exercise end-points based on fractions of heart rate reserve (HR(res))], as an alternative to the traditional time-based calculation. Twenty-nine healthy sedentaries >60 years of age (18 males, 11 females) performed an incremental cycling exercise to exhaustion. Respiratory variables and HR were measured breath by breath. Resting and peak variables were calculated and ventilatory threshold (VT) was identified by standard technique. OUES was calculated on 75, 90 and 100% of the incremental exercise data (OUES75, OUES90, OUES100) and on data corresponding to 60 and 80% of the HR(res) (OUES60%HR(res), OUES80%HR(res)). No significant difference (repeated measures ANOVA) was detected between time-based (OUES100, OUES90, OUES75) as well as HR(res)-based measures of OUES (OUES80%HR(res), OUES60%HR(res)). The Bland-Altman analysis revealed a bias not significantly different from 0 (22.0 and 53.3 for OUES80%HR(res)-OUES100 and OUES60%HR(res)-OUES100, respectively), a precision of 171.2 and 289.0 and 95% limits of agreement from -313 to +358 and from -513 to +620 for OUES80%HR(res)-OUES100 and for OUES60%HR(res)-OUES100, respectively. High correlations were detected between (VO(2peak)) and OUES60%(res) and OUES80%HR(res) (r (2) = 0.70 and 0.81, respectively) and between VT and OUES60%(res) and OUES80%HR(res) (r (2) = 0.58 and 0.66, respectively). The main finding of this study is that OUES can be reliably calculated based on HR(res) end-points during incremental cycling exercise, in healthy elderly subjects. Furthermore, our study confirms the validity of OUES as an indicator of aerobic exercise capability in this population.

The Oxygen Uptake Efficiency Slope

“…Among these studies, the OUES has been investigated in healthy adults (n ϭ 7), 4,[24][25][26][27][28][29] in adult patients with a chronic condition (n ϭ 15), 4,8,14,18,21,22,28,[30][31][32][33][34][35][36] and in children (n ϭ 5). 19,21,[37][38][39] The results of aforementioned studies are described below.…”

“…4,27,29 One study 28 even demonstrated that OUES values calculated from the first half of exercise did not significantly differ from values calculated from the second half or the entire exercise test data. However, another study reported significantly higher values of OUES calculated from data up to 75% and 85% of maximal running speed than those obtained from the entire test data.…”

“…28 The relationship with the VAT appeared to be moderately high to strong (r ϭ 0.66, r ϭ 0.76, r ϭ 0.78 for maximal OUES; r ϭ 0.59, r ϭ 0.75, r ϭ 0.80, r ϭ 0.83, r ϭ 0.70 for submaximal OUES). 26,27,29 …”

Test–retest reliability of the oxygen uptake efficiency slope in surgical patients

“…With exercise, the requirement for ventilation increases with oxygen uptake and in patients with cardiorespiratory disease, greater ventilatory effort is required as oxygen uptake rises; this is manifest as a decrease in the oxygen uptake efficiency slope. In addition to not requiring maximal effort, the determination of the oxygen uptake efficiency slope from the respiratory data requires no subjective interpretation of the exercise data [7,15], in contrast to the anaerobic threshold, which may be difficult to identify [16,17] and is subject to observer error [18].…”

Maximal and submaximal oxygen uptake efficiency slope: influence of cardiorespiratory variables and maximal dynamic strength

“…It is interesting to note that the OUES determination is not influenced by some intervenient factors, such as the use of experienced and nonexperienced evaluators or test protocol [12]. Moreover, the OUES measurement can be performed without necessarily require a maximal effort or additional experimental sessions [16].…”