The Effect of Blood Volume Variations on the Pulse Rate in Supine and Upright Positions and During Exercise1

Gullbring B., A. Holmgren, T. Sjostrand and T. Strandell. The effect of blood volume variations on the pulse rate in supim and upright positions and during txercice. The effect of bleeding of about 10 per cent of the blood volume and reinfusion of this quantity of blood seven days later was studied in six male subjects. The study includes determination of the pulse rate at rest in supine and upright positions and during exercise on a bicycle ergometer. The physical working capacity (PWC170) was computed from the pulse rates during work. The pulse rate in upright position and during exercise increases and PWC170 decreases immediately after the bleeding. During the next few days PWC170 increases and the pulse rate in upright position and during exercise decreases, while the pulse rate in supine position appeared to increase. On the sixth day PWC170 was found to be higher and the pulse rate in supine and upright positions and during exercise to be lower than before the bleeding. Reinfusion of the blood seemed to produce a further moderate increase in PWC170. The decrease in PWC170 after the bleeding corresponded, on the whole, to the average relation in different individuals between PWC170 and the total amount of hemoglobin. The respiratory rate during exercise increased after the bleeding and also showed the same tendency as the pulse rate did during exercise and in upright position during the next few days.