Abstract des Autors

Seven male subjects were studied before and up to 53 days after the loss of 1 l blood. The resting hematocrit fell from 44.0 to 38,7 and returned to control level after 3 weeks. Maximal oxygen uptake decreased from 4.00 l/min to 3.54 l/min and returned to the initial level within 2 weeks. Submaximal oxygen uptake, pulmonary ventilation, maximal heart rate and blood lactate were not found to change significantly. Submaximal heart rate was increased from 125 beats/min to about 135 beats/min and remained elevated for 3 weeks, whereas blood lactate was increased only in the first weeks. Maximal work timedecreased from 5.1 min to 3.8 min and remained low for the first 2 weeks, but rose thereafter above the starting level. Comparison with a control study suggested that there is some training effect, which when allowed for, indicates that maximal work time returns to starting values at the same time as does the maximal oxygen uptake. It is concluded that the drop in Hct, maximal oxygen uptake and work capacity, found after the loss of 1 l of blood, are related to each other both in magnitude and duration.