Effects of Resistance Exercise on Iron Absorption and Balance in Iron-Deficient Rats

Abstract

We have previously reported that resistance exercise improved the iron status in iron-deficient rats. The current study investigated the mechanisms underlying this exercise-related effect. Male 4-week-old rats were divided into a group sacrificed at the start (week 0) (n = 7), a group maintained sedentary for 6 weeks (S) or a group that performed exercise for 6 weeks (E), and all rats in the latter groups were fed an iron-deficient diet (12 mg iron/kg) for 6 weeks. The rats in the E group performed climbing exercise (5 min × 6 sets/day, 3 days/week). Compared to the week 0 rats, the rats in the S and E groups showed lower tissue iron content, and the hematocrit, hemoglobin, plasma iron, and transferrin saturation values were all low. However, the tissue iron content and blood iron status parameters, and the whole body iron content measured using the whole body homogenates of the rats, did not differ between the S group and the E group. The messenger RNA (mRNA) expression levels of hepcidin, duodenal cytochrome b, divalent metal transporter 1, and ferroportin 1 did not differ between the S group and the E group. The apparent absorption of iron was significantly lower in the E group than in the S group. Therefore, it was concluded that resistance exercise decreases iron absorption, whereas the whole body iron content is not affected, and an increase in iron recycling in the body seems to be responsible for this effect.

Impact of resistance training and basic ferritin on hepcidin, iron status and some inflammatory markers in overweight/obese girls

“…Five weeks of intense treadmill training in mice increases hepcidin expression and induced anemia due to exercise[ 25 ] and reduction of serum iron and ferritin. [ 25 26 ] This result has also been observed in human participants. [ 11 ] However, increasing expression of divalent metal transporter-1 and ferroportin-1 (FPN-1) in intestinal cells resulted in an increase in iron absorption following a moderate-intensity training compared to the control group.…”

Effects of an Acute Exercise Bout on Serum Hepcidin Levels

“…In rodents, compared to endurance, resistance training has been presented as a better strategy for improving blood hemoglobin concentration in iron-deficient rats, potentially due to an increased heme synthesis [ 79 , 80 ]. Remarkably, this type of exercise seems to promote an elevation of iron absorption caused by an increase of recycled iron [ 81 ]. Nevertheless, despite the promising results of resistance exercise in iron metabolism [ 82 ], the effects of this exercise type—whether alone or in combination with endurance exercise—on hepcidin concentrations remains to be elucidated in humans.…”

Effect of acute aerobic exercise in different times of day on iron status and hematological factors in professional football players

“…The reduction, increase, and the stability of the iron levels are reported as a result of exercise activity (3). Further, the iron status and hematological parameters as a result of exercise activity depend on several factors such as the amount of iron excretion (16), RBC hemolysis (17,18), intestinal absorption (19), andiron retention (20), along with the change and conversion of erythrocytes and Hb (21) or inflammation (22). A decrease in the levels of iron, ferritin, and RBC in intense exercise activity can be attributed to the hemolysis due to the stroke, which is related to the intensity of the exercise and the increase in temperature by 6%-11% excretion through sweating (3).…”

“…A decrease in the levels of iron, ferritin, and RBC in intense exercise activity can be attributed to the hemolysis due to the stroke, which is related to the intensity of the exercise and the increase in temperature by 6%-11% excretion through sweating (3). Furthermore, the reduction of iron levels resulted from extreme sports activities is possibly due to a decline in the transfer of bivalent metal (Divalent metal transporter-1), Ferroportin 1, the carrier protein (Haem carrier protein-1), hephaestin, and ceruloplasmin (9,19). The results of this study showed that RBC and Hb levels in the morning and evening exercise groups were significantly higher than those in the control groups after the aerobic activity, while the iron and ferritin levels decreased significantly.…”