Changes in urinary zinc and copper with strenuous physical exercise

BACKGROUND: Air rescue trainees in the Japan Air Self Defense Force participate in a curriculum that includes 24 wk of strenuous physical training. The trace minerals zinc and copper are directly involved in many physiologic processes that are altered by physical exercise of this sort. It has also been demonstrated that urinary excretion of catecholamines (adrenaline and noradrenaline) increases during both mental work and physical exercise. HYPOTHESIS: Air rescue trainees will exhibit changes in trace mineral excretion and catecholamine levels that vary with the type of training undertaken. METHODS: The levels of urinary zinc (Zn), copper (Cu), noradrenaline (NAd), and adrenaline (Ad) were determined in 11 air rescue trainees before and after daily training sessions for consecutive 3- or 4-d periods during four phases of the curriculum, as follows: control (Cont), classroom instruction without physical exercise; preliminary (Prelim), daily exercise sessions for increased physical strength; basic (Basic), a combination of lectures and demanding physical exercise; and simulated mountain rescue (Sim). RESULTS: The mean urinary concentrations of Zn and Cu increased significantly after sessions with physical exercise (Prelim, Basic, and Sim), but remained unchanged for Cont. The NAd levels also increased significantly after training with physical exercise. In contrast, Ad levels increased significantly after sessions in all phases, both with and without physical exercise. CONCLUSIONS: The urinary levels of Zn, Cu, NAd, and Ad rose with strenuous exertion, whereas only Ad responded to both physical and mental tasking.