Whereas endurance exercise is known to induce marked neutrophilia, it remains to be
fully understood as to whether the cell functions are altered as well as whether the
adaptability of the responses to training occurs. To address both of these issues,
we undertook the present longitudinal investigaticon in ten healthy untrained men
(20 - 24 years, VO2max 39.1 ± 4.2 ml/kg/min). The exercise protocol was 7 consecutive sessions of the
same workload performed each day for 1.5 h at an intensity of 70 % of VO2max. Peripheral blood samples were obtained before, immediately after, and 1 h after
exercise on Days 1, 4, and 7, and served for determination of total and differential
leukocyte counts, chemotaxis and chemiluminescence (of neutrophils. Acute endurance
exercise caused marked peripheral neutrophilia with significant increase in both absolute
number and relative proportion of band neutrophils (p < 0.01, respectively), indicating
partial recruitment of bone marrow neutrophils. While chemotaxis remained unaltered
following exercise, reactive oxygen species generation of neutrophils, measured by
luminol-dependent chemiluminescence upon stimulation with opsonized zymosan, was not
only significantly enhanced following exercise (p < 0.01), but also associated with
the proportional increase in band neutrophils (r = 0.727, p < 0.05), suggesting that
neutrophils mobilized from the bone marrow following endurance exercise may possess
higher responsiveness. On the other hand, the magnitude of the exercise-induced changes
was reduced gradually by daily repeated exposure to endurance exercise, but none of
the trends were significant except the decline in resting segmented neutrophil counts
(p < 0.05) at least during a 1-wk period of repeated exercise sessions.
Key words
Exercise - leukocytosis - neutrophils - shift to the left - chemotaxis - chemiluminescence
- free radicals - stress
