Respiratory respones to sinusoidal work load in man. Relationships among amplitude respones, phase response and aerobic capacity / 体力科学

ABSTRACT

Amplitude and phase response of ventilation (V<SUB>E</SUB>), carbon dioxide output (VCO<SUB>2</SUB>) and oxygen uptake (VO<SUB>2</SUB>) during sinusoidally varying work load for periods (T) of 1-16 min were studied in six healthy men. The relationships between these parameters and aerobic capacity (VO<SUB>2</SUB>max, ATVO<SUB>2</SUB>) were also examined. The results and conclusions obtained were as follows<BR>(1) The relationship between the period (T) of exercise and amplitude response of VO<SUB>2</SUB>, VCO<SUB>2</SUB> and V<SUB>E</SUB> was well described by first-order exponential models. However, the relationship between the period of exercise and the phase shift (phase responses of VO<SUB>2</SUB>, VCO<SUB>2</SUB>, and V<SUB>E</SUB>) 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.<BR>(2) High negative correlations were observed between the steady-state amplitude (A) of phase response or the time constants (r) of amplitude response and VO<SUB>2</SUB>max, and ATVO<SUB>2</SUB>. Significantly high negative correlations for all gas exchange parameters may be more rapid in individuals with greater aerobic capacity.<BR>(3) A close relationship between the response of VCO<SUB>2</SUB> and V<SUB>E</SUB> was demonstrated by a higher correlation coefficient than that between VO<SUB>2</SUB> and VCO<SUB>2</SUB> or between VO<SUB>2</SUB> and V<SUB>E</SUB>. This can be partly, but not completely, explained by the cardiodynamic theory.