Effect of Training on Zinc Metabolism: Changes in Serum and Sweat Zinc Concentrations in Sportsmen

Abstract

The purpose of this research was to determine the effects of daily physical training on serum and sweat zinc concentrations in professional sportsmen between October and December, during the competing season. Twelve volleyball players and another 12 control subjects have participated in this study. Tests were made in October and December which consisted of a progressive bicycle ergometer test (increasing 30 W every 3 min to reach maximum tolerated power). Blood samples were obtained at rest and immediately after exercise. Total serum zinc increased significantly after maximal exercise in both sportsmen and control subjects. In athletes, the change after exercise was significantly higher in December than in October. The percentage of ultrafiltrable zinc (ZnUf) in October was similar in sportsmen and in controls. In December, however, after exercise, the percentage of ZnUf was higher in athletes. With respect to sweat zinc, it was in the same range both in controls and in sportsmen in October. In December, however, sweat zinc was significantly higher in athletes as compared with the situation in October and with respect to the control group. In October, the zinc concentration of urine was similar for sportsmen and controls. In December, the sportsmen showed an increase in urinary zinc excretion with respect to control subjects. Cortisol in athletes increased significantly after exercise in December. In conclusion, a daily and maintained practice of exercise is probably responsible for an alteration of zinc metabolism. The results suggest that ZnUf control, zinc supplementation and/or stress control appear to be indicated in athletes to prevent the diminution of active ZnUf. In our practical opinion we think that alterations in zinc metabolism with increases in zinc excretion and stress levels lead to a situation of latent fatigue with a decreased endurance.

Comparison of plasma leptin and zinc levels in elite athletes and sedentary people

“…Low muscle zinc level will consequently reduce the endurance capacity. 27 Both serum leptin and serum zinc were significantly lower in the elite weightlifters, relative to the control group in our study. The decrease in serum leptin levels may have resulted from long-term regular exercises' increasing fat metabolism and reducing the level of body fat rate, thereby leading to a decrease in plasma leptin.…”

Effect of zinc supplementation on lipid peroxidation and lactate levels in rats with diabetes induced by streptozotocin and subjected to acute swimming exercise

“…Acute exercise (45,46) and diabetes (3,44) were found to show a marked increase in zinc-supplemented diabetic groups (groups 3 and 6), relative to groups 4, 7 and 8, indicates the importance of zinc supplementation in association with exercise and diabetes. Several researchers showed that serum zinc values decreased after exercise (45,46,47). Elevated levels of zinc we found in zinc-supplemented swimming group (group 5) point out the signifi cance of zinc supplementation in association with exercise.…”

“…This fi nding we obtained in group 4 indicates that acute swimming exercise signifi cantly suppresses serum zinc levels. It was argued that daily and regular exercise could be responsible for the impairment in zinc metabolism and that impairments in zinc metabolism as well as zinc loss could lead to muscle exhaustion and weakness (45). Bordin et al (46) demonstrated that physical exercise led to re-distribution of zinc among body stores, blood and tissues, and the increased metabolism caused zinc defi ciency.…”

Bedeutung von Sport und Ernährung für die körperliche Leistungsfähigkeit und Gesundheit - Ein systematischer Review

“…Bei Volleyballern konnte man wäh-rend der Trainingsperiode eine progressive Zunahme der Zinkausscheidung im Harn und im Schweiss messen [37]. Auch bei japanischen Soldaten nahm während einer intensiven 24-wöchigen Trainingsperiode die Ausscheidung von Zink und Kupfer im Harn zu [38].…”