K. Shirakawa

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We investigated ventilation (V . E) control factors during recovery from light impulse-like exercise (100 watts) with a duration of 20 sec. Blood ions and gases were measured at rest and during recovery. V . E, end tidal CO 2 pressure (PETCO 2) and respiratory exchange ratio (RER) were measured continuously during rest, exercise and recovery periods.(More)
Many studies have failed to show that pre-sleep exercise has a negative effect on sleep onset. However, since only a moderate level of physiological excitement was observed at bedtime in these studies, it remains unclear whether a larger magnitude of physiologic excitement present at bedtime would disrupt sleep onset. This study compared the effects of(More)
The aim of the present study was to compare the oscillations of oxygenation in skeletal muscle between early and late phases in prolonged exercise. During prolonged exercise at 60 % of peak oxygen uptake (V(.)o(2)) for 60 min and at rest, oxygenated hemoglobin/myoglobin (Hb/MbO(2)) and total Hb/Mb (THb/Mb) were determined by near-infrared spectroscopy in(More)
Effort sense has been suggested to be involved in the hyperventilatory response during intense exercise (IE). However, the mechanism by which effort sense induces an increase in ventilation during IE has not been fully elucidated. The aim of this study was to determine the relationship between effort-mediated ventilatory response and corticospinal(More)
The purpose of this study was to determine whether tissue oxygen indices (TOIs) in two muscle groups oscillated and were synchronized in repetition of impulse exercise with high intensity. Five impulse exercises of 400 watts for 10 s were repeated with intervals of 6 min. During this period, TOI was determined by near-infrared spectroscopy in the vastus(More)
The aim of the present study was to determine the effects of voluntary breathing on corticospinal excitability of a leg muscle during isometric contraction. Seven subjects performed 5-s isometric knee extension at the intensity of 10% of maximal voluntary contraction (10% MVC). During the 10% MVC, the subjects were instructed to breath normally (NORM) or to(More)
The purpose of the present study was to compare oscillation of skin blood flow with that of deoxygenation in muscle during light exercise in order to determine the physiological significance of oscillations in deoxygenation. Prolonged exercise with 50% of peak oxygen uptake was performed for 60 min. Skin blood flow (SBF) was measured using a laser blood(More)
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