Theytelluswhentogetuporwhenwe’rerunninglateforworkandwhetherweareindangerofmissingourfavouriteTVprogramme.Butwhileourdailyroutinesrelyonclocksthattellusthetimescienceisdiscoveringthatourwell-beingisinfluencedbyaverydifferentkindoftimepiece.Circadianrhythms---thehumanbody’sowninternalclock---haveapowerfulinfluenceonourhealthandbehaviour.Theyareprogrammedfrombirthandcontrolfunctionsrangingfromtemperatureandbloodpressuretosleeppatterns.
Inrecentyearsresearchershavealsodiscoveredthatthisbuilt-inmechanismcaninfluenceeverythingfromthewaywereacttomedicinestohowwellwelearnmusic.
ThelatestexamplefromexpertsatHarvardUniversityintheUSshowsthatthehumanbodyclockcanevendictatewhetherornotwearelikelytotellthetruth.Researchersfounditwaseasierforpeopletofib（撒小谎）intheafternoonbecauseastheyweretiredtheselfcontrolthatwouldnormallypreventthemfromlyingstartedtobreakdown.Tirednessmadeithardertoresistthetemptationtotelllies---especiallyifitmeanttheygotafinancialrewardattheend.
“Thebodyclockhasagreateffectonusall”saysProfessorJimHornefromtheSleepResearchCentreatLoughboroughUniversity.“Mostpeopletendtofeelgoodaroundlatemorningandthendeclineintheearlyafternoon.Butthetimemostofuswillfeeloursharpestisbetween6pmand8pm.That’sbecausesleepinesstendstobuildupthroughouttheday.Byearlyeveningourbodyclockkicksintowakeusup.Onereasonmaybetoensurewegethomesafely.Whenourancestorswerecominghomeafterhuntingalldaytheirinternalclockskickedintogetthemhomeinonepiece.”
Sowhateffectsdocircadianrhythmshaveandwhat’sthebesttimeofdaytotakeadvantageofthem?
【小题1】Theunderlinedword“They”inthefirstparagraphrefersto .
