Respiratory response to sinusoidal work load in man -relationships among amplitude response, phase response and aerobic capacity-

Abstract

Amplitude and phase response of ventilation ([formula omitted]), carbon dioxide output ([formula omitted]) and oxygen uptake ([formula omitted]) during sinusoidally varying work load for periods (T) of l∼16 min were studied in six healthy men. The relationships between these parameters and aerobic capacity ([formula omitted]max, AT[formula omitted]) were also examined. The results and conclusions obtained were as follows : (1) The relationship between the period (T) of exercise and amplitude response of [formula omitted], [formula omitted] and [formula omitted] was well described by first-order exponential models. However, the relationship between the period of exercise and the phase shift (phase responses of [formula omitted], [formula omitted], and [formula omitted]) was better described by complex models comprising a first-order exponential function and a linear equation. This can be explained by Karpman's threshold theory. (2) High negative correlations were observed between the steady-state amplitude (A) of phase response or the time constants (r) of amplitude response and [formula omitted]max, and AT[formula omitted]. Significantly high negative correlations for all gas exchange parameters may be more rapid in individuals with greater aerobic capacity. (3) A close relationship between the response of [formula omitted] and [formula omitted] was demonstrated by a higher correlation coefficient than that between [formula omitted] and [formula omitted] or between [formula omitted] and [formula omitted]. This can be partly, but not completely, explained by the cardiodynamic theory.(Jpn. J. Phys. Fitness Sports Med. 1991, 40 : 60∼73). © 1991, The Japanese Society of Physical Fitness and Sports Medicine. All rights reserved.