Oxygen-Uptake Efficiency Slope in Healthy 7- to 18-Year-Old Children

Blagoi Marinov, Stoilka Mandadzhieva, Stefan Kostianev
2007 Pediatric Exercise Science  
The aim of this article was to assess the oxygen-uptake efficiency slope (OUES) throughout the age span of 7 to 18 years. One hundred fourteen healthy children (58 boys and 56 girls) exercised on a treadmill by means of a modified Balke protocol. The OUES grew in a nonlinear pattern with age, and it appeared to be significantly higher in boys than in girls. There was a very strong correlation between OUES and VO 2peak (r = .92), and there was a small difference between the values of OUES
more » ... ted for different exercise intensities. Stepwise-regression analysis outlined body surface area (BSA) and sex as main determinants of OUES. OUES is an objective measure of exercise capacity that does not require a maximal effort but is considerably dependent on anthropometric variables and necessitates the generation of appropriate reference values. Understanding the cardiorespiratory functional-reserve changes that occur throughout childhood and adolescence is a major issue in developmental exercise physiology. Data are usually limited to maximal oxygen uptake (VO 2max ) (1,15,21), which has always been an intensively sought paradigm, but in certain populations with obesity, chronic diseases, or low fitness levels it is generally difficult to obtain (16). VO 2max is effort dependent and therefore largely influenced by one's motivation (3,23). Several research groups have already proposed a number of submaximal indices for evaluating functional capacity without requiring participants to perform maximal exercise (6, 9, 12) . In 1996 Baba et al., in an endeavor to develop an objective and independent measure of cardiorespiratory reserve, introduced the oxygen-uptake efficiency slope (OUES)-a single-segment logarithmic curvefitting model describing the ventilatory response to exercise. It was initially applied to a cohort of children with heart disease (3) and later validated by Hollenberg and Tager (10) on a large sample of adults. The latter also proposed prediction equations for the OUES in adults. Baba et al. (2) reported excellent reproducibility of the OUES, and Van Laethem et al. (22) recently proved that it is stable over the entire exercise duration and significantly correlated with VO 2peak . As the method gained popularity, the OUES was incorporated into research for evaluating exercise tolerance (4), monitoring the effects of exercise rehabilitation programs (20), detecting the improvement of cardiorespiratory reserve after endurance training (13), and predicting the outcomes of heart-transplant patients (13). Recently, Davies et al. The authors are with the
doi:10.1123/pes.19.2.159 pmid:17603139 fatcat:6y3c2pinjzeudjsic47mk6sbla