title: Exponential hyperbolic sine function fitting of heart rate response to constant load exercise.
abstract: We attempted to fit heart rate (HR) changes induced by constant exercise loads of different intensities to an exponential hyperbolic sine curve by the least-squares method, and we compared the results with the fitting of the changes to exponential curves. Seven healthy male volunteers performed three different intensities of constant-load exercise on a bicycle ergometer. The exponential hyperbolic sine function adequately fitted the HR responses induced by all three different intensities of loads: low (30 W: correlation coefficient, r = 0.68 +/- 0.13, mean +/- SD), moderate (75 W: r = 0.93 +/- 0.07) and high (125 W: r = 0.97 +/- 0.02). The first-order exponential curve fitted only the moderate load response. Although the second-order exponential equation fitted the HR response for both the moderate and high loads, the equation did not fit the low-load response (r = 0.43 +/- 0.26). In low-load exercise, the sum of the power of the residuals for the exponential hyperbolic sine curve fitting was significantly smaller than that for the first- or second-order exponential curve fitting. In conclusion, the exponential hyperbolic sine function is useful for quantitative analyses of the HR response to exercise loads of various intensities.
authors.affiliation: Department of Internal Medicine I, Faculty of Medicine, Okayama University Medical School, Okayama, 700-8558 Japan.
authors.forename: J
authors.initials: J
authors.lastname: Mizuo
authors.forename: T
authors.initials: T
authors.lastname: Nakatsu
authors.forename: T
authors.initials: T
authors.lastname: Murakami
authors.forename: S
authors.initials: S
authors.lastname: Kusachi
authors.forename: Y
authors.initials: Y
authors.lastname: Tominaga
authors.forename: K
authors.initials: K
authors.lastname: Mashima
authors.forename: T
authors.initials: T
authors.lastname: Uesugi
authors.forename: H
authors.initials: H
authors.lastname: Ueda
authors.forename: C
authors.initials: C
authors.lastname: Suezawa
authors.forename: T
authors.initials: T
authors.lastname: Tsuji
mesh_terms: D000328:Adult; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007700:Kinetics; D016018:Least-Squares Analysis; D008297:Male; D008955:Models, Cardiovascular; D005082:Physical Exertion / Q000502:physiology*