Int J Sports Med 2004; 25(7): 516-521
DOI: 10.1055/s-2004-820952
Physiology & Biochemistry

© Georg Thieme Verlag KG Stuttgart · New York

The Effects of Physical Exercise on the Concentrations of Ferritin and Transferrin Receptor in Plasma of Male Judoists

J. Malczewska1 , R. Stupnicki2 , W. Błach3 , E. Turek-Lepa4
  • 1Department of Nutrition Physiology, Institute of Sport, Warsaw, Poland
  • 2Department of Biometry, Academy of Physical Education, Warsaw, Poland
  • 3Department of Sports Methodology, Academy of Physical Education, Wrocław, Poland
  • 4Department of Antidoping Research, Institute of Sport, Warsaw, Poland
Further Information

Publication History

Accepted after revision: October 15, 2003

Publication Date:
26 July 2004 (online)

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Abstract

The aim of the study was to assess the within-subject (day-to-day) variability for iron status variables: ferritin (ferr) and soluble transferrin receptor (sTfR) concentrations in plasma and the sTfR/log ferr index in athletes subjected daily to high physical loads. Blood was sampled in the morning from 8 healthy male elite judoists, aged 20 - 31 years, for 10 consecutive days while at training camp. Mean concentrations of ferritin and sTfR in plasma for the 10 day period were 32.0 · 1.771± 1 and 2.41 · 1.324 ± 1 mg/l, respectively. The average within-subject, day-to-day variability for ferritin was 27.4 % (range: 16 - 44 %), and was much lower for sTfR (6.7 %; range: 4 - 15 %). Ferritin concentrations were significantly, albeit weakly, correlated with training loads on the preceding day (r = 0.256; p < 0.05) and with creatine kinase (CK) activities on the same day (r = 0.397; p < 0.001), while sTfR did not correlate with either training loads or CK activities. Mean day-to-day variability for the sTfR/log ferr index was 11.8 % (range: 5 - 21 %), i.e. markedly lower than for ferritin. Although the physical load-induced changes in iron metabolism indices in male subjects were similarly oriented as in the earlier reported female ones representing the same sport, the magnitude of those changes was less pronounced than in the females. This was evidenced by a markedly lower within-subject day-to-day variability in ferritin, still significant but weak correlation between load magnitude and ferritin levels, and a significant, negative correlation between ferritin and sTfR concentrations, not found previously in the female athletes. However, despite lower variability in ferritin than in women , the exercise-induced ferritin increases in male athletes might make a reliable assessment of iron stores in them difficult. The present results confirm our earlier reports that sTfR levels are stable under high physical loads, thus making them a useful indicator of iron status. Also sTfR/log ferr index is of a much higher diagnostic value than ferritin, despite high variability of the latter. That index is particularly valuable in detecting iron-deficient erythropoiesis.

References

Dr Jadwiga Malczewska

Institute of Sport

Trylogii 2

01-982 Warsaw 45

Poland

Fax: + 48 22 8 35 09 77

Email: jadwiga.malczewska@insp.waw.pl