Tomoaki Matsuo1,2, Rina So3,4, Masaya Takahashi4. 1. Occupational Epidemiology Research Group, National Institute of Occupational Safety and Health, Japan, 6-21-1, Nagao, Tama-ku, Kawasaki, 214-8585, Japan. matsuo@crf-res.net. 2. Research Center for Overwork-Related Disorders, National Institute of Occupational Safety and Health, Japan, Kawasaki, Japan. matsuo@crf-res.net. 3. Occupational Epidemiology Research Group, National Institute of Occupational Safety and Health, Japan, 6-21-1, Nagao, Tama-ku, Kawasaki, 214-8585, Japan. 4. Research Center for Overwork-Related Disorders, National Institute of Occupational Safety and Health, Japan, Kawasaki, Japan.
Abstract
PURPOSE: Step test protocols are typically based on the heart rate (HR) measured either during exercise or during recovery. This study developed a new step test protocol to estimate maximal oxygen consumption ([Formula: see text]) based on HRs measured during and after exercise, assessed the criterion validity of the model, and evaluated the protocol's test-retest reliability. METHODS: The protocol estimates [Formula: see text] from HR measurements made once a minute during 3 min of step exercise and 2 min of recovery. The model was derived using a group of 118 working adults and cross-validated using a second group of 74 working adults. Furthermore, [Formula: see text] was measured using a conventional treadmill test. While multiple regression analyses were used to develop prediction equations for [Formula: see text], intraclass correlation coefficients (ICCs) were used to examine test-retest reliability. RESULTS: HRs during and after exercise significantly correlated with the measured [Formula: see text]. The highest correlation (r = - 0.61) was for an HR index that combined values of HRs during and after exercise. A model including age, sex, body mass index, and the HR index accounted for 60% of the variance in measured [Formula: see text] (standard error of the estimate, 4.05 mL kg-1 min-1 or 10.5%). Cross-validation analyses demonstrated good stability of the [Formula: see text] prediction models. The ICC for the HR index was 0.65 (0.53-0.74), indicating fair to good reliability. CONCLUSION: The HR index, based on a combination of HR measurements during and after stepping exercise, offers a validated [Formula: see text] estimation procedure suitable for use in the workplace.
PURPOSE: Step test protocols are typically based on the heart rate (HR) measured either during exercise or during recovery. This study developed a new step test protocol to estimate maximal oxygen consumption ([Formula: see text]) based on HRs measured during and after exercise, assessed the criterion validity of the model, and evaluated the protocol's test-retest reliability. METHODS: The protocol estimates [Formula: see text] from HR measurements made once a minute during 3 min of step exercise and 2 min of recovery. The model was derived using a group of 118 working adults and cross-validated using a second group of 74 working adults. Furthermore, [Formula: see text] was measured using a conventional treadmill test. While multiple regression analyses were used to develop prediction equations for [Formula: see text], intraclass correlation coefficients (ICCs) were used to examine test-retest reliability. RESULTS: HRs during and after exercise significantly correlated with the measured [Formula: see text]. The highest correlation (r = - 0.61) was for an HR index that combined values of HRs during and after exercise. A model including age, sex, body mass index, and the HR index accounted for 60% of the variance in measured [Formula: see text] (standard error of the estimate, 4.05 mL kg-1 min-1 or 10.5%). Cross-validation analyses demonstrated good stability of the [Formula: see text] prediction models. The ICC for the HR index was 0.65 (0.53-0.74), indicating fair to good reliability. CONCLUSION: The HR index, based on a combination of HR measurements during and after stepping exercise, offers a validated [Formula: see text] estimation procedure suitable for use in the workplace.