Sportsmedicineexpertshaveobservedforyearsthatathletessuchaslongdistancerunnersespeciallywomenathletesoftendisplayalackofiron.NowanewstudybyateamofPurdueUniversityresearcherssuggeststhatevenmoderateexer
Sportsmedicineexpertshaveobservedfor yearsthatathletessuchaslongdistancerunnersespeciallywomenathletesoftendisplayalackofiron.NowanewstudybyateamofPurdueUniversityresearcherssuggeststhatevenmoderateexercisemayleadtoreducedironinthebloodofwomen.
"Wefoundthatwomenwhowerenormallyinactiveandthenstartedaprogramofmoderateexerciseofmiddledegreeshowedsingsofironloss"saysRoseanneM.LyleassociateprofessoratPurdue.Herstudyof62formerlyinactivewomenwhobeganexercisingthreetimesaweekforsixmonthswaspublishedinthejournalMedicine&ScienceinSports&Exercise.
Irondeficiencyisverycommonamongwomeningeneralaffectingoneinfourfemaleteenagersandoneinfivewomenaged18to45respectively.Buttheratioisevengreateramongactivewomenaffectingupto80percentoffemaleenduranceathletes.ThismeansLylesaysthat"toomanywomenignoretheamountofirontheytakein".Womenofchild-bearingageareatgreatestrisksincetheirmonthlybleedingisamajorsourceofironloss.Plusmanyhealth-consciouswomenincreasetheirriskbyrejectingredmeatwhichcontainsthemosteasilyabsorbedformofiron.Andbecausewomenoftenrestricttheirdietinanefforttocontrolweighttheymaynotconsumeenoughiron-richfoodandareliabletoexperienceadeficiency.
Exercisecanresultinironlossthroughavarietyofmechanisms.Someironislostinsweatandforunknownreasonsintenseenduranceexerciseissometimesassociatedwithbleedingofthedigestivesystem.Athletesinhigh-impactsportssuchasrunningmayalsoloseironthroughaphenomenonwheresmallbloodvesselsinthefeetleakblood.
Therearethreestagesofirondeficiency.Thefirstandmostcommonishavinglowironreservesaconditionthattypicallyhasnosymptoms.Fatigueandpoorperformancemaybegintoappearinthesecondstageofdeficiencywhennotenoughironispresenttoformthemolecules(分子)ofbloodproteinthattransportoxygentotheworkingmuscles.Inthethirdandfinalstagepeopleoftenfeelweaktiredandoutofbreath-andexerciseperformanceisseverelycompromised.
"Peoplethinkthatifthey'renotatthethirdstagenothingiswrongbutthat'snottrue"
