Effect of exercise on iron metabolism in horses.
Abstract: We investigated the effect of exercise on iron metabolism in horses. Four horses were walked on a mechanical walker for 1 wk (pre-exercise). They then performed moderate exercise on a high-speed treadmill in the first week of the exercise and relative high in the second week and high in the third week. Serum iron was significantly lower in the third week of exercise than in the pre-exercise. Transferrin saturation (TS) was significantly lower in the first and third weeks of exercise than in the pre-exercise. Serum haptoglobin was significantly lower in the first week of exercise than in the pre-exercise and further significantly lower in the second and third weeks than in the first. The packed cell volume did not change during the experiment. The exercise significantly increased the apparent absorption of iron. Urinary iron excretion did not change throughout the experiment. Sweat iron loss did not change during the exercise. The exercise significantly increased iron balance. We considered that hemolysis is induced by moderate exercise and is further enhanced by heavy exercise, which decreases serum iron and TS. However, the increase in iron absorption compensates for the adverse effect of exercise on iron status. Therefore, exercise does not induce anemia in horses.
Publication Date: 2005-09-20 PubMed ID: 16170220DOI: 10.1385/BTER:107:1:033Google Scholar: Lookup
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- Journal Article
Summary
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The study examines how exercise impacts iron metabolism in horses, demonstrating that while heavy exercise can reduce serum iron and transferrin saturation (TS), it also increases iron absorption, preventing anemia.
Methodology
- The experiment involved four horses, which were purposely walked on a mechanical walker for one week to monitor their iron metabolism before exercise.
- This pre-exercise period was followed by a three-week exercise program on a high-speed treadmill, where the intensity of the exercise was gradually increased, from moderate in the first week, relatively high in the second week, to high in the third week.
Measurements and Findings
- Several factors related to iron metabolism were measured throughout the experiment, including serum iron levels, transferrin saturation (TS), serum haptoglobin, packed cell volume, urinary iron excretion, sweat iron loss, and overall iron balance.
- The findings suggested that serum iron was significantly lower during the third week of exercise compared to the pre-exercise period, indicating that heavy exercise could reduce iron levels.
- Transferrin saturation (TS) was found to be significantly lower in the first and third weeks of exercise than in the pre-exercise period, demonstrating that exercise could similarly impact TS levels.
- On the other hand, serum haptoglobin was significantly lower in the first week of exercise than in the pre-exercise period, but it was significantly lower still in the second and third weeks than in the first week. This result suggested a gradual reduction in haptoglobin levels throughout the period of exercise.
Effect on Iron Absorption and Excretion
- Interestingly, the exercise significantly increased the horses’ apparent absorption of iron, implying a compensatory mechanism to maintain iron levels during periods of exertion.
- Iron excretion in the urine and loss in sweat did not change throughout the experiment, suggesting that exercise does not affect these aspects of iron metabolism.
- The exercise also significantly increased the iron balance, indicating an overall positive impact on iron metabolism despite the initial reductions in serum iron and TS.
Conclusion
- The study concluded that while heavy exercise could induce hemolysis (breakdown of red blood cells), leading to decreased serum iron and TS, the compensatory increase in iron absorption helps to maintain the iron status, preventing exercise-induced anemia in horses.
Cite This Article
APA
Inoue Y, Matsui A, Asai Y, Aoki F, Matsui T, Yano H.
(2005).
Effect of exercise on iron metabolism in horses.
Biol Trace Elem Res, 107(1), 33-42.
https://doi.org/10.1385/BTER:107:1:033 Publication
Researcher Affiliations
- Equine Science Division, Hidaka Training and Research Center, Japan Racing Association, 535-13 Aza-Nishicha, Urakawa-cho, Urakawa-gun, Hokkaido 057-0171, Japan.
MeSH Terms
- Animals
- Body Weight
- Diet
- Haptoglobins / analysis
- Hematocrit
- Horses
- Iron / blood
- Iron / metabolism
- Physical Conditioning, Animal
Citations
This article has been cited 11 times.- Satué K, Fazio E, La Fauci D, Medica P. Hematological indexes and iron status in pregnant mares. Arch Anim Breed 2023;66(3):197-205.
- Bollinger L, Bartel A, Weber C, Gehlen H. Pre-Ride Biomarkers and Endurance Horse Welfare: Analyzing the Impact of the Elimination of Superoxide Dismutase, δ-Aminolevulinic-Dehydratase, Thiobarbituric Acid Reactive Substances, Iron, and Serum Amyloid A Levels in Elite 160 km Endurance Rides. Animals (Basel) 2023 May 17;13(10).
- Satué K, Fazio E, La Fauci D, Medica P. Changes of Hepcidin, Ferritin and Iron Levels in Cycling Purebred Spanish Mares. Animals (Basel) 2023 Mar 31;13(7).
- Mihelić K, Vrbanac Z, Bojanić K, Kostanjšak T, Ljubić BB, Gotić J, Vnuk D, Bottegaro NB. Changes in Acute Phase Response Biomarkers in Racing Endurance Horses. Animals (Basel) 2022 Oct 31;12(21).
- Wijekoon S, Tsogbadrakh M, Sunaga T, Wang Y, Mwale C, Kim S, Alimaa D, Okumura M. Pentosan polysulfate regulates hepcidin expression in native Mongolian horses. J Vet Med Sci 2022 Oct 7;84(10):1437-1441.
- Ghio AJ, Soukup JM, Ghio C, Gordon CJ, Richards JE, Schladweiler MC, Snow SJ, Kodavanti UP. Iron and zinc homeostases in female rats with physically active and sedentary lifestyles. Biometals 2021 Feb;34(1):97-105.
- McGivney BA, Griffin ME, Gough KF, McGivney CL, Browne JA, Hill EW, Katz LM. Evaluation of microRNA expression in plasma and skeletal muscle of thoroughbred racehorses in training. BMC Vet Res 2017 Nov 22;13(1):347.
- Mach N, Plancade S, Pacholewska A, Lecardonnel J, Rivière J, Moroldo M, Vaiman A, Morgenthaler C, Beinat M, Nevot A, Robert C, Barrey E. Integrated mRNA and miRNA expression profiling in blood reveals candidate biomarkers associated with endurance exercise in the horse. Sci Rep 2016 Mar 10;6:22932.
- Kristensen L, Buhl R, Nostell K, Bak L, Petersen E, Lindholm M, Jacobsen S. Acute exercise does not induce an acute phase response (APR) in Standardbred trotters. Can J Vet Res 2014 Apr;78(2):97-102.
- Kiełbik P, Witkowska-Piłaszewicz O. Iron Status in Sport Horses: Is It Important for Equine Athletes?. Int J Mol Sci 2025 Jun 12;26(12).
- Hisaeda K, Ono T, Shimokawa-Miyama T, Hata A, Iwata E, Hiasa Y, Ohzawa E, Tozaki T, Murase H, Takasu M, Nishii N, Kitagawa H. Differences in serum iron concentrations between the summer and winter in Noma horses. J Equine Sci 2025;36(1):1-9.
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