Leukocyte, lymphocyte and platelet response to dynamic exercise

The influence of work intensity and duration on the white blood cell (WBC), lymphocyte (L) and platelet (P) count response to exercise was studied in 16 trained subjects (22±5.4 years, \(\bar x\) ±SD). They performed three cyclo-ergospirometric protocols: A) 10 min at 150 W followed by a progressive test (30 W/3 min) till exhaustion; B) constant maximal work ( \(\dot V_{{\text{O}}_{\text{2}} {\text{max}}}\) ); C) a 45 min Square-Wave Endurance Exercise Test (SWEET), (n=5). Arterial blood samples were taken: at rest, submaximal and maximal exercise in A; maximal exercise in B; 15^th, 30^th and 45^th min in the SWEET. Lactate, [H⁺], PaCO₂, PaO₂, [Hct], Hb, cortisol, ACTH, total platelet volume (TPV), total blood red cell (RBC), WBC, L and P were measured. At 150 W, WBC, L, P, and TPV increased. \(\dot V_{{\text{O}}_{\text{2}} {\text{max}}}\) did not differ between A and B, but a difference was found in total exercise time (A=25±3 min; B=7±2 min, p<0.001). In A, at \(\dot V_{{\text{O}}_{\text{2}} {\text{max}}}\) , the increase was very small for Hct, [Hb], and RBC (10%), in contrast with large changes for WBC (+93%), L (+137%), P (+32%), TPV (+35%), [H⁺] (+39%), lactate (+715%), and ACTH (+95%). At \(\dot V_{{\text{O}}_{\text{2}} {\text{max}}}\) there were no differences in these variables between A and B. During the SWEET: WBC, L, P, TPV and ACTH increased at the 15^th min as much as in \(\dot V_{{\text{O}}_{\text{2}} {\text{max}}}\) , but no difference was observed between the 15^th, 30^th and 45^th min, except for ACTH which continued to rise; the lactate increase during the SWEET was about half (+341%) the value observed at \(\dot V_{{\text{O}}_{\text{2}} {\text{max}}}\) , and [H⁺] did not vary with respect to values at rest. The data show that the increase in WBC, L, P, and TPV is small in submaximal exercise but larger at \(\dot V_{{\text{O}}_{\text{2}} {\text{max}}}\) and during the SWEET; high intensity plays a greater role than the total time of exercise in the variation, and haemoconcentration, cortisol and acidosis seem to have little influence.