Effect of maximal exercise on the short-term kinetics of zinc metabolism in sedentary males

Stella Lucia Volpe ^1*, Nicola M Lowe ², Leslie R Woodhouse ³ and Janet C King ⁴

¹ University of Pennsylvania, United States
² University of Central Lancashire, United Kingdom
³ University of California, United States
⁴ Children's Hospital Oakland Research Institute, United States

^* To whom correspondence should be addressed. E-mail: svolpe{at}nursing.upenn.edu.

Accepted 8 November 2006

Abstract

Objective: The purpose of this study was to examine the effect of acute exhaustive exercise versus rest on short-term zinc kinetics in males.

Design: This was a cross-over design, whereby all subjects were their own control.

Setting: This was a university setting, subjects were free-living.

Participants: Twelve, healthy, sedentary males, 25 to 35 years of age.

Interventions: 70Zn was infused 10 minutes post-exercise or at rest. Plasma zinc concentrations were measured at baseline and 2, 5, 10, 15, 30, 45, 60, 75, 90, and 120 minutes following exercise or rest. Hematocrit was measured pre- and post-exercise to assess plasma volume changes.

Main Outcome Measurements: Plasma zinc (primary), serum creatine kinase (CK), and serum cortisol concentrations (secondary).

Results: Plasma zinc concentrations decreased (P < 0.05) after exercise; with a nadir of 13.9 ± 4.1% observed at 70 minutes post-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 appears to cause a shift of plasma zinc into the interstitial fluid and liver post-exercise, which may reflect the acute stress response of strenuous exercise.

Key Words: Exercise, Kinetics, Stable Isotopes, Stress, Zinc

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