CIRCULATORY CHANGES DURING MUSCULAR EXERCISE 1057 



so that the second mechanism of adaptation, viz. quickening of the heart 

 beat, will be sooner brought into action to cope with the increased inflow 

 associated with muscular exercise. Thus one finds a considerable difference 

 in the effect of exercise on the pulse rate in trained and untrained individuals 

 respectively, and this is specially shown in the rate of recovery in the pulse 

 when the exercise comes to an end, the effects lasting much longer in the 

 untrained. In all cases exercise not carried to exhaustion tends to be fol- 

 lowed by a prolonged diminution both in pulse rate and in blood pressure 

 (cf. Fig. 485). 



67 



