LEUKOCYTE AND ERYTHROCYTE COUNTS DURING A MULTISTAGE CYCLING RACE (THE MILK-RACE)

Venous blood samples were taken from eight competitors in mid-evening after a racing day, and in the early morning before the next day's rac e, three times during the course of the Milk Race, 1992. These were us ed to gather information about the changes in circulating leucocyte le vels in response to the exceptionally high sustained daily workload re quired during a major multi-stage race. The primary objective was to p rovide knowledge of 'normal' values against which future clinical judg ements of abnormality might be made in these unusual circumstances. Du ring the race, estimated energy output was about 25 MJ (6000 kCal)/day . The mean total circulating leucocyte numbers (per litre of blood), a nd those of individual leucocyte classes (neutrophil, lymphocyte, mono cyte, eosinophil and basophil) were all inside the normal range both i n the morning and in the evening. Evening counts were, however, 30-50% higher than morning counts, for all classes except eosinophils. We co nclude that individual clinical decisions about leucocyte levels can b est be made using normal (sedentary man) values if a morning sample is taken.