title: Anaerobic Threshold and Salivary α-amylase during Incremental Exercise.
abstract: [Purpose] The purpose of this study was to clarify the validity of salivary α-amylase as a method of quickly estimating anaerobic threshold and to establish the relationship between salivary α-amylase and double-product breakpoint in order to create a way to adjust exercise intensity to a safe and effective range. [Subjects and Methods] Eleven healthy young adults performed an incremental exercise test using a cycle ergometer. During the incremental exercise test, oxygen consumption, carbon dioxide production, and ventilatory equivalent were measured using a breath-by-breath gas analyzer. Systolic blood pressure and heart rate were measured to calculate the double product, from which double-product breakpoint was determined. Salivary α-amylase was measured to calculate the salivary threshold. [Results] One-way ANOVA revealed no significant differences among workloads at the anaerobic threshold, double-product breakpoint, and salivary threshold. Significant correlations were found between anaerobic threshold and salivary threshold and between anaerobic threshold and double-product breakpoint. [Conclusion] As a method for estimating anaerobic threshold, salivary threshold was as good as or better than determination of double-product breakpoint because the correlation between anaerobic threshold and salivary threshold was higher than the correlation between anaerobic threshold and double-product breakpoint. Therefore, salivary threshold is a useful index of anaerobic threshold during an incremental workload.
authors.affiliation: Department of Rehabilitation, Misato Central General Hospital, Japan ; Graduate School of Health Sciences, Ibaraki Prefectural University of Health Sciences, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Akizuki
authors.affiliation: Department of Rehabilitation, Nerima Hikarigaoka Hospital, Japan.
authors.forename: Syouichirou
authors.initials: S
authors.lastname: Yazaki
authors.affiliation: Department of Rehabilitation, Misato Central General Hospital, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Echizenya
authors.affiliation: Department of Physical Therapy, Ibaraki Prefectural University of Health Sciences, Japan.
authors.forename: Yukari
authors.initials: Y
authors.lastname: Ohashi
keywords: Anaerobic threshold; Salivary threshold; Salivary α-amylase