Abstract

Objective: To examine the effect of acute exhaustive exercise versus rest on short-term zinc kinetics in men.

Design: Crossover design, wherein all subjects were their own control.

Setting: University setting, where subjects were free living.

Participants: 12 healthy, sedentary men, 25–35 years of age.

Interventions:⁷⁰Zn was infused 10 min after exercise or at rest. Plasma zinc concentrations were measured at baseline and 2, 5, 10, 15, 30, 45, 60, 75, 90 and 120 min after exercise or rest. Haematocrit was measured before and after exercise to assess changes in plasma volume.

Main outcome measurements: Plasma zinc (primary), serum creatine kinase and serum cortisol concentrations (secondary).

Results: Plasma zinc concentrations decreased (p<0.05) after exercise, with a mean (SD) nadir of 13.9% (4.1%) observed at 70 min after exercise. There were increases in the size of the rapidly exchangeable plasma zinc pool (Qa; from 3.1 (0.2) to 3.6 (0.2) mg; p<0.05) and the liver zinc pool (Qb; from 10.2 (0.6) to 11.4 (0.8) mg; p = 0.12).

Conclusion: Exercise seems to cause a shift of plasma zinc into the interstitial fluid and liver after exercise, which may reflect the acute stress response of strenuous exercise.