Abstract

Some basic haematological characteristics of a group of competitive swimmers were compared with haematological “normal standards” and with a “control” group of non-athletes, unmatched for age. In the women, the values for red blood cell count, haemoglobin concentration, and mean red cell volume for both the swimmers and the controls were not significantly different from the normal standards. In the groups of men, both swimmers and controls, red cell counts were significantly lower than the normal standard values, although individual values lay within the “normal range” (mean ± 2 standard deviations).

The ranges of the values for individuals were found to be narrow. There were no significant differences between these ranges over periods of five consecutive weeks and five consecutive months. Relatively large changes in results for individuals could occur before the results would be considered abnormal, that is, before the results fall outside the “normal range”. Early detection of changes may perhaps be facilitated if the range of values for individual athletes is determined by monitoring.