sports Article Quantification and Verification of Cardiorespiratory Fitness in Adults with Prehypertension Dharini M. Bhammar 1, * and Lung-Chang Chien 2   Citation: Bhammar, D.M.; Chien, L.-C. Quantification and Verification of Cardiorespiratory Fitness in Adults with Prehypertension. Sports 2021, 9, 9. https://doi.org/10.3390/ sports9010009 Received: 1 December 2020 Accepted: 6 January 2021 Published: 11 January 2021 Publisher’s Note: MDPI stays neu- tral with regard to jurisdictional clai- ms in published maps and institutio- nal affiliations. Copyright: © 2021 by the authors. Li- censee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and con- ditions of the Creative Commons At- tribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Department of Kinesiology and Nutrition Sciences, School of Integrated Health Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154, USA 2 Department of Epidemiology and Biostatistics, School of Public Health, University of Nevada Las Vegas, Las Vegas, NV 89154, USA; Lung-Chang.Chien@unlv.edu * Correspondence: Dharini.Bhammar@unlv.edu Abstract: Background: Low cardiorespiratory fitness is associated with increased risk of hypertension and atherosclerosis in adults with prehypertension. The purpose of this study was to quantify cardiorespiratory fitness and to examine the utility of supramaximal constant-load verification testing for validating maximal oxygen uptake (VO 2max ) attainment in adults with prehypertension. Methods: Eleven adults (four women) with prehypertension (22.5 ± 2.9 y; body mass index (BMI): 24.6 ± 3.2 kg·m 2 ) underwent an incremental exercise test followed 15 min later by a verification test at 105% of maximal work rate on a cycle ergometer. Results: There was no statistical difference in VO 2 between the incremental (2.23 ± 0.54 L·min -1 ) and verification tests (2.28 ± 0.54 L·min -1 ; p = 0.180). Only three out of eleven participants had a higher VO 2 during the verification when compared with the incremental test. If the verification test had not been conducted, one participant would have been incorrectly classified as having low cardiorespiratory fitness based on incremental test results alone. Conclusions: Verification testing validates the attainment of VO 2max and can potentially reduce the over-diagnosis of functional impairment (i.e., deconditioning) in adults with prehypertension. Keywords: blood pressure; aerobic fitness; 3-min all-out exercise test; VO 2max ; deconditioning 1. Introduction Prehypertension affects one in three adults in the United States [1] and is associated with an increased risk of hypertension [2] as well as cardiovascular morbidity and mortal- ity [3]. Low cardiorespiratory fitness in adults with prehypertension is associated with an increased risk of hypertension [4] and atherosclerosis [5]. Previous studies that have exam- ined the associations between cardiorespiratory fitness and health outcomes in adults with prehypertension have typically quantified cardiorespiratory fitness relative to body weight (i.e., as mL·min -1 ·kg -1 ) or metabolic equivalents (MET) or treadmill test duration, and they have used treadmill as the mode of exercise for fitness assessments [4,6–10]. While treadmill testing per se may not affect maximal oxygen uptake (VO 2max ) levels, the use of exercise test duration from a treadmill protocol as a surrogate for VO 2max can negatively influence performance in individuals who carry excess body weight [11]. These traditional methods of quantifying cardiorespiratory fitness could inaccurately underestimate fitness levels in individuals with overweight or obesity, who are also at increased risk of high blood pressure [12], and can confound the associations between cardiorespiratory fitness and negative health outcomes [13]. Both the American Thoracic Society (ATS) [14] and the American Heart Association (AHA) [15] recommend quantifying cardiorespiratory fitness as a percent of predicted VO 2max , where predicted VO 2max is calculated based on ideal body weight. This approach can reduce the underestimation of cardiorespiratory fitness in overweight and obese individuals [16]. Cardiopulmonary exercise testing provides an assessment of VO 2max or the highest amount of oxygen that can be delivered by the cardiorespiratory system and utilized by the Sports 2021, 9, 9. https://doi.org/10.3390/sports9010009 https://www.mdpi.com/journal/sports