The Effects of Acute Exercise on Hepcidin in Women

Abstract

PURPOSE: The purpose of this study was to investigate the effects of acute exercise on serum hepcidin and iron levels in active women. Changes in Interluekin-6 (IL-6), hepcidin, ferritin, and serum iron in response to 2 different exercise durations were compared. METHODS: Twelve women 19-32 yrs performed 2 treadmill runs (60 and 120 minutes) at a pace that elicited 65% of VO2max. The order of the trials was randomized and counterbalanced. Blood samples were obtained prior to, immediately post, 3, 6, 9 and 24 hrs following exercise. Post-exercise measures were corrected for plasma volume shifts. Two-way repeated measures ANOVA was conducted to examine changes in measured variables. Significance was accepted at p<0.05. RESULTS: Significant main effects for time and trial were observed for hepcidin (60 min: 1.15 ± 0.48 nmol/L; 120 min: 2.28 ± 1.44 nmol/L). Hepcidin concentrations were significantly increased 3 hrs post-exercise for both trials (60 min (nmol/L): pre - 0.73 ± 0.56, post - 0.96 ± 0.69, 3h - 1.99 ± 2.00, 6h- 1.40 ± 1.20, 9h - 1.06 ± 0.75, 24h - 0.76 ± 0.52; 120 min (nmol/L): pre - 1.07 ± 0.99, post - 1.29 ± 1.00, 3h - 4.60 ± 4.61, 6h - 3.47 ± 4.11, 9h - 1.92 ± 1.74, 24h - 1.33 ± 1.61) Significant main effects for time occurred for serum iron, ferritin, and IL-6. Serum iron significantly decreased at 9 hrs post-exercise compared to 3 hrs and 24 hrs post-exercise. A significant increase in IL-6 occurred immediately post exercise (3.94 ± 2.40 pg/ml), with a return to baseline by 24 hrs post. Ferritin concentrations increased immediately post exercise and were significantly different than 24 h post-exercise ferritin level. CONCLUSIONS: Both submaximal runs resulted in significant increases in hepcidin 3 hrs after exercise. Increases in hepcidin were preceded by a significant increase in IL-6 immediately after exercise, and were followed by a significant decrease in serum iron at 9 hrs postexercise. It was concluded that endurance exercise increases the production of hepcidin which affects serum iron. Two hour exercise bouts stimulate greater hepcidin levels than one hour exercise bouts. The results suggest that women frequently participating in endurance exercise are at risk for low iron status due to increases in hepcidin, and should monitor iron status closely. Supported by an ACSM Foundation Grant