Abstract
The main purpose of this study was to investigate the level of agreement between the gas exchange threshold (GET) and heart rate variability threshold (HRVT) during maximal cardiopulmonary exercise testing (CPET) using three different exercise modalities. A further aim was to establish whether there was a 1:1 relationship between the percentage heart rate reserve (%HRR) and percentage oxygen uptake reserve () at intensities corresponding to GET and HRVT. Sixteen apparently healthy men 17 to 28 years of age performed three maximal CPETs (cycling, walking, and running). Mean heart rate and at GET and HRVT were 16 bpm (P<0.001) and 5.2 mL·kg-1·min-1 (P=0.001) higher in running than cycling, but no significant differences were observed between running and walking, or cycling and walking (P>0.05). There was a strong relationship between GET and HRVT, with R2 ranging from 0.69 to 0.90. A 1:1 relationship between %HRR and was not observed at GET and HRVT. The %HRR was higher during cycling (GET mean difference=7%; HRVT mean difference=11%; both P<0.001), walking (GET mean difference=13%; HRVT mean difference=13%; both P<0.001), or running (GET mean difference=11%; HRVT mean difference=10%; both P<0.001). Therefore, using HRVT to prescribe aerobic exercise intensity appears to be valid. However, to assume a 1:1 relationship between %HRR and at HRVT would probably result in overestimation of the energy expenditure during the bout of exercise.
Highlights
Appropriate prescription of aerobic exercise intensity is important for the safety and effectiveness of training programs [1]
The gas exchange threshold (GET) is often considered as an effective method to prescribe exercise intensity because it is closely related to the tolerance for prolonged exercise [3,4,5]
The main purpose of the present study was to investigate the level of agreement between GET and heart rate variability threshold (HRVT) during maximal cardiopulmonary exercise testing (CPET) performed within three different exercise modalities
Summary
Appropriate prescription of aerobic exercise intensity is important for the safety and effectiveness of training programs [1]. Aerobic exercise intensity can be prescribed using work rate, heart rate, and ratings of perceived exertion, among other methods [2]. A recent position paper on exercise prescription in cardiac rehabilitation [6] recommended a change from ‘‘rangebased’’ to ‘‘threshold-based’’ approaches. This recommendation supports the use of:the heart rate reserve (HRR) and oxygen uptake reserve (VO2 R) at GET as markers of the transition between light-to-moderate and moderate-to-high effort intensity domains. The high cost of equipment and required expertise, sometimes precludes
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