The Impact of Morning versus Afternoon Exercise on Iron Absorption in Athletes

Rachel McCormick, Diego Moretti, Alannah K.A. McKay, Coby M. Laarakkers, Rachel Vanswelm, Debbie Trinder, Gregory R. Cox, Michael B. Zimmerman, Marc Sim, Carmel Goodman, Brian Dawson, Peter Peeling

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Abstract

Purpose This study examined postexercise inflammatory, hepcidin, and iron absorption responses to endurance exercise performed in the morning versus the afternoon. Methods Sixteen endurance-trained runners (10 male, 6 female) with serum ferritin (sFer) < 50 μg·L-1 completed a 90-min running protocol (65% vVO2max) in the morning (am), or the afternoon (pm), in a crossover design. An iron-fortified fluid labeled with stable iron isotopes (57Fe or 58Fe) was administered with a standardized meal 30 min following the exercise and control conditions during each trial, serving as a breakfast and dinner meal. Venous blood samples were collected before, immediately after, and 3 h after the exercise and control conditions to measure sFer, serum interleukin-6 (IL-6), and serum hepcidin-25. A final venous blood sample was collected 14 d after each trial to determine the erythrocyte iron incorporation, which was used to calculate iron absorption. Linear mixed-modeling was used to analyze the data. Results Overall, exercise significantly increased the concentrations of IL-6 (4.938 pg·mL-1; P = 0.006), and hepcidin-25 concentrations significantly increased 3 h after exercise by 0.380 nM (P < 0.001). During the pm trial, hepcidin concentrations exhibited diurnal tendency, increasing 0.55 nM at rest (P = 0.007), before further increasing 0.68 nM (P < 0.001) from prerun to 3 h postrun. Fractional iron absorption was significantly greater at breakfast after the am run, compared with both the rested condition (0.778%; P = 0.020) and dinner in the am run trial (0.672%; P = 0.011). Conclusions Although exercise resulted in increased concentrations of IL-6 and hepcidin, iron was best absorbed in the morning after exercise, indicating there may be a transient mechanism during the acute postexercise window to promote iron absorption opposing the homeostatic regulation by serum hepcidin elevations.

Original languageEnglish
Pages (from-to)2147-2155
Number of pages9
JournalMedicine and Science in Sports and Exercise
Volume51
Issue number10
DOIs
Publication statusPublished - 1 Oct 2019

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Hepcidins
Athletes
Iron
Exercise
Meals
Interleukin-6
Serum
Breakfast
Ferritins
Iron Isotopes
Running
Cross-Over Studies
Erythrocytes

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McCormick, R., Moretti, D., McKay, A. K. A., Laarakkers, C. M., Vanswelm, R., Trinder, D., ... Peeling, P. (2019). The Impact of Morning versus Afternoon Exercise on Iron Absorption in Athletes. Medicine and Science in Sports and Exercise, 51(10), 2147-2155. https://doi.org/10.1249/MSS.0000000000002026
McCormick, Rachel ; Moretti, Diego ; McKay, Alannah K.A. ; Laarakkers, Coby M. ; Vanswelm, Rachel ; Trinder, Debbie ; Cox, Gregory R. ; Zimmerman, Michael B. ; Sim, Marc ; Goodman, Carmel ; Dawson, Brian ; Peeling, Peter. / The Impact of Morning versus Afternoon Exercise on Iron Absorption in Athletes. In: Medicine and Science in Sports and Exercise. 2019 ; Vol. 51, No. 10. pp. 2147-2155.
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title = "The Impact of Morning versus Afternoon Exercise on Iron Absorption in Athletes",
abstract = "Purpose This study examined postexercise inflammatory, hepcidin, and iron absorption responses to endurance exercise performed in the morning versus the afternoon. Methods Sixteen endurance-trained runners (10 male, 6 female) with serum ferritin (sFer) < 50 μg·L-1 completed a 90-min running protocol (65{\%} vVO2max) in the morning (am), or the afternoon (pm), in a crossover design. An iron-fortified fluid labeled with stable iron isotopes (57Fe or 58Fe) was administered with a standardized meal 30 min following the exercise and control conditions during each trial, serving as a breakfast and dinner meal. Venous blood samples were collected before, immediately after, and 3 h after the exercise and control conditions to measure sFer, serum interleukin-6 (IL-6), and serum hepcidin-25. A final venous blood sample was collected 14 d after each trial to determine the erythrocyte iron incorporation, which was used to calculate iron absorption. Linear mixed-modeling was used to analyze the data. Results Overall, exercise significantly increased the concentrations of IL-6 (4.938 pg·mL-1; P = 0.006), and hepcidin-25 concentrations significantly increased 3 h after exercise by 0.380 nM (P < 0.001). During the pm trial, hepcidin concentrations exhibited diurnal tendency, increasing 0.55 nM at rest (P = 0.007), before further increasing 0.68 nM (P < 0.001) from prerun to 3 h postrun. Fractional iron absorption was significantly greater at breakfast after the am run, compared with both the rested condition (0.778{\%}; P = 0.020) and dinner in the am run trial (0.672{\%}; P = 0.011). Conclusions Although exercise resulted in increased concentrations of IL-6 and hepcidin, iron was best absorbed in the morning after exercise, indicating there may be a transient mechanism during the acute postexercise window to promote iron absorption opposing the homeostatic regulation by serum hepcidin elevations.",
author = "Rachel McCormick and Diego Moretti and McKay, {Alannah K.A.} and Laarakkers, {Coby M.} and Rachel Vanswelm and Debbie Trinder and Cox, {Gregory R.} and Zimmerman, {Michael B.} and Marc Sim and Carmel Goodman and Brian Dawson and Peter Peeling",
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McCormick, R, Moretti, D, McKay, AKA, Laarakkers, CM, Vanswelm, R, Trinder, D, Cox, GR, Zimmerman, MB, Sim, M, Goodman, C, Dawson, B & Peeling, P 2019, 'The Impact of Morning versus Afternoon Exercise on Iron Absorption in Athletes' Medicine and Science in Sports and Exercise, vol. 51, no. 10, pp. 2147-2155. https://doi.org/10.1249/MSS.0000000000002026

The Impact of Morning versus Afternoon Exercise on Iron Absorption in Athletes. / McCormick, Rachel; Moretti, Diego; McKay, Alannah K.A.; Laarakkers, Coby M.; Vanswelm, Rachel; Trinder, Debbie; Cox, Gregory R.; Zimmerman, Michael B.; Sim, Marc; Goodman, Carmel; Dawson, Brian; Peeling, Peter.

In: Medicine and Science in Sports and Exercise, Vol. 51, No. 10, 01.10.2019, p. 2147-2155.

Research output: Contribution to journalArticleResearchpeer-review

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T1 - The Impact of Morning versus Afternoon Exercise on Iron Absorption in Athletes

AU - McCormick, Rachel

AU - Moretti, Diego

AU - McKay, Alannah K.A.

AU - Laarakkers, Coby M.

AU - Vanswelm, Rachel

AU - Trinder, Debbie

AU - Cox, Gregory R.

AU - Zimmerman, Michael B.

AU - Sim, Marc

AU - Goodman, Carmel

AU - Dawson, Brian

AU - Peeling, Peter

PY - 2019/10/1

Y1 - 2019/10/1

N2 - Purpose This study examined postexercise inflammatory, hepcidin, and iron absorption responses to endurance exercise performed in the morning versus the afternoon. Methods Sixteen endurance-trained runners (10 male, 6 female) with serum ferritin (sFer) < 50 μg·L-1 completed a 90-min running protocol (65% vVO2max) in the morning (am), or the afternoon (pm), in a crossover design. An iron-fortified fluid labeled with stable iron isotopes (57Fe or 58Fe) was administered with a standardized meal 30 min following the exercise and control conditions during each trial, serving as a breakfast and dinner meal. Venous blood samples were collected before, immediately after, and 3 h after the exercise and control conditions to measure sFer, serum interleukin-6 (IL-6), and serum hepcidin-25. A final venous blood sample was collected 14 d after each trial to determine the erythrocyte iron incorporation, which was used to calculate iron absorption. Linear mixed-modeling was used to analyze the data. Results Overall, exercise significantly increased the concentrations of IL-6 (4.938 pg·mL-1; P = 0.006), and hepcidin-25 concentrations significantly increased 3 h after exercise by 0.380 nM (P < 0.001). During the pm trial, hepcidin concentrations exhibited diurnal tendency, increasing 0.55 nM at rest (P = 0.007), before further increasing 0.68 nM (P < 0.001) from prerun to 3 h postrun. Fractional iron absorption was significantly greater at breakfast after the am run, compared with both the rested condition (0.778%; P = 0.020) and dinner in the am run trial (0.672%; P = 0.011). Conclusions Although exercise resulted in increased concentrations of IL-6 and hepcidin, iron was best absorbed in the morning after exercise, indicating there may be a transient mechanism during the acute postexercise window to promote iron absorption opposing the homeostatic regulation by serum hepcidin elevations.

AB - Purpose This study examined postexercise inflammatory, hepcidin, and iron absorption responses to endurance exercise performed in the morning versus the afternoon. Methods Sixteen endurance-trained runners (10 male, 6 female) with serum ferritin (sFer) < 50 μg·L-1 completed a 90-min running protocol (65% vVO2max) in the morning (am), or the afternoon (pm), in a crossover design. An iron-fortified fluid labeled with stable iron isotopes (57Fe or 58Fe) was administered with a standardized meal 30 min following the exercise and control conditions during each trial, serving as a breakfast and dinner meal. Venous blood samples were collected before, immediately after, and 3 h after the exercise and control conditions to measure sFer, serum interleukin-6 (IL-6), and serum hepcidin-25. A final venous blood sample was collected 14 d after each trial to determine the erythrocyte iron incorporation, which was used to calculate iron absorption. Linear mixed-modeling was used to analyze the data. Results Overall, exercise significantly increased the concentrations of IL-6 (4.938 pg·mL-1; P = 0.006), and hepcidin-25 concentrations significantly increased 3 h after exercise by 0.380 nM (P < 0.001). During the pm trial, hepcidin concentrations exhibited diurnal tendency, increasing 0.55 nM at rest (P = 0.007), before further increasing 0.68 nM (P < 0.001) from prerun to 3 h postrun. Fractional iron absorption was significantly greater at breakfast after the am run, compared with both the rested condition (0.778%; P = 0.020) and dinner in the am run trial (0.672%; P = 0.011). Conclusions Although exercise resulted in increased concentrations of IL-6 and hepcidin, iron was best absorbed in the morning after exercise, indicating there may be a transient mechanism during the acute postexercise window to promote iron absorption opposing the homeostatic regulation by serum hepcidin elevations.

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McCormick R, Moretti D, McKay AKA, Laarakkers CM, Vanswelm R, Trinder D et al. The Impact of Morning versus Afternoon Exercise on Iron Absorption in Athletes. Medicine and Science in Sports and Exercise. 2019 Oct 1;51(10):2147-2155. https://doi.org/10.1249/MSS.0000000000002026