[Effects of long-term swimming exercise on iron status of rats].

AIM: To observe the effects of different periods of exercise on the iron status.

METHODS: Female rats were randomly divided into 3-, 6-, 12-month swimming exercise groups and their corresponding sedentary groups. The hematological indices of iron status and the non-heme iron (NHI) and total NHI (TNHI) of the organs were determined at the end of the desired period.

RESULTS: As compared with the corresponding sedentary groups, plasma iron and transferrin-iron saturation of three exercise groups were decreased without significant changes of blood hemoglobin and hematocrit. The NHI contents and TNHI of the liver, spleen and kidney were decreased. Although the NHI contents of the heart decreased, TNHI was not significantly changed. TNHI of the organs in both the exercised and sedentary rats were found to increase with age.

CONCLUSION: The exercise-induced low iron status with depleted iron storage is similar to the iron-deficiency status, but it could not be explained using the hypothesis of iron deficiency. Both the NHI redistribution and the maintained iron storage suggests the adaptation of low iron status to exercise. Therefore, the so-called exercise-induced iron deficiency could not exist.