Open AccessUse of the HR index to predict maximal oxygen uptake during different exercise protocols
Author(s) -
Haller Jeannie M.,
Fehling Patricia C.,
Barr David A.,
Storer Thomas W.,
Cooper Christopher B.,
Smith Denise L.
Publication year - 2013
Publication title -
physiological reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 39
ISSN - 2051-817X
DOI - 10.1002/phy2.124
Subject(s) - vo2 max , treadmill , mathematics , standard error , cycle ergometer , energy expenditure , statistics , medicine , physical therapy , heart rate , blood pressure
This study examined the ability of the HR index model to accurately predict maximal oxygen uptake ( V ˙ O 2max ) across a variety of incremental exercise protocols. Ten men completed five incremental protocols to volitional exhaustion. Protocols included three treadmill (Bruce, UCLA running, Wellness Fitness Initiative [ WFI ]), one cycle, and one field (shuttle) test. The HR index prediction equation (METs = 6 × HR index − 5, where HR index = HR max / HR rest ) was used to generate estimates of energy expenditure, which were converted to body mass‐specific estimates of V ˙ O 2max . Estimated V ˙ O 2max was compared with measured V ˙ O 2max . Across all protocols, the HR index model significantly underestimated V ˙ O 2max by 5.1 mL·kg −1 ·min −1 (95% CI: −7.4, −2.7) and the standard error of the estimate ( SEE ) was 6.7 mL·kg −1 ·min −1 . Accuracy of the model was protocol‐dependent, with V ˙ O 2max significantly underestimated for the Bruce and WFI protocols but not the UCLA, Cycle, or Shuttle protocols. Although no significant differences in V ˙ O 2max estimates were identified for these three protocols, predictive accuracy among them was not high, with root mean squared errors and SEEs ranging from 7.6 to 10.3 mL·kg −1 ·min −1 and from 4.5 to 8.0 mL·kg −1 ·min −1 , respectively. Correlations between measured and predicted V ˙ O 2max were between 0.27 and 0.53. Individual prediction errors indicated that prediction accuracy varied considerably within protocols and among participants. In conclusion, across various protocols the HR index model significantly underestimated V ˙ O 2max in a group of aerobically fit young men. Estimates generated using the model did not differ from measured V ˙ O 2max for three of the five protocols studied; nevertheless, some individual prediction errors were large. The lack of precision among estimates may limit the utility of the HR index model; however, further investigation to establish the model's predictive accuracy is warranted.