Abstract

A study was conducted to elucidate the changes in circulatory responses to sudden strenuous exercise (SSE) using beat-by-beat analysis of heart rate (HR), stroke volume (SV) and blood pressure (BP). The effects of warming-up on these responses were also studied. Six healthy male students volunteered for the study. A bicycle ergometer was prepared for SSE. The intensity and duration of SSE were 100 VO2max and 1 min, respectively. Warming-up of 80 VO2max for 5 min was followed by SSE. The interval between SSE and warming-up varied from 5 to 30 min. A control experiment was also performed without warming-up. The main results obtained were as follows: 1) BP decreased in the initial stage of SSE, followed by a steep increase. This temporary drop in BP was prevented by warming-up. This might contribute to the prevention of myocardial ischemia which is occasionally observed in the initial stage of SSE without warming-up. 2) Time constants of HR and SV during SSE were shortened by warming-up with long intervals, while the time constant of BP was shortened when the interval was short. 3) The recovery response of each parameter was accelerated by warming-up, but the effect of warming-up had almost disappeared after a 30 min interval. These results suggest the following conclusions: Warming-up accelerates the up-stroke and recovery of circulatory responses to SSE, but these effects of warming-up are strongly influenced by interval time. In particular, the effect of recovery acceleration is almost abolished by a 30 min interval. Verf.-Referat