【LONDON—Here’sanewwarningfromhealthexperts：Sittingisdeadly.Scientistsareincreasinglywarningthatsittingforlongperiods—evenifyoualsoexerciseregularly—couldbebadforyourhealth.Anditdoesn’tmatterwherethes】
LONDON—Here’sanewwarningfromhealthexperts：Sittingisdeadly.
Scientistsareincreasinglywarningthatsittingforlongperiods—evenifyoualsoexerciseregularly—couldbebadforyourhealth.Anditdoesn’tmatterwherethesittingtakesplace—attheoffice，atschool，inthecarorbeforeacomputerorTV—justtheoverallnumberofhoursitoccurs.Severalstudiessuggestpeoplewhospendmostoftheirdayssittingaremorelikelytobefat，haveaheartattackorevendie.
InaneditorialpublishedthisweekintheBritishJournalofSportsMedicine，ElinEkblomBakoftheSwedishSchoolofSportandHealthSciencessuggestedthatauthoritiesrethinkhowtheydefinephysicalactivitytohighlightthedangersofsitting.
Whilehealthofficialshaveissuedguidelinesrecommendingminimumamountsofphysicalactivity，theyhaven’tsuggestedpeopletrytolimithowmuchtimetheyspendinaseatedposition.
“Afterfourhoursofsitting，thebodystartstosendharmfulsignals，”saidEkblomBak.Sheexplainedthatgenesregulating(调节)theamountofglucose(葡萄糖)andfatinthebodystarttoshutdown.
Evenforpeoplewhoexercise，spendinglongperiodsoftimesittingatadeskisstillharmful.TimArmstrong，aphysicalactivityexpertattheWorldHealthOrganization，saidpeoplewhoexerciseeveryday—butstillspendalotoftimesitting—mightgetmorebenefitifthatexercisewasspreadacrosstheday，ratherthaninasinglebout(一回)．
Still，inastudypublishedin2009thattrackedmorethan17000Canadiansforaboutadozenyears，researchersfoundpeoplewhosatmorehadahigherdeathrisk，whetherornottheyexercised.
“Wedon’thaveenoughevidenceyettosayhowmuchsittingisbad，”saidPeterKatzmarzykofthePenningtonBiomedicalResearchCenterinBatonRouge，wholedtheCanadianstudy.“Butitseemsthemoreyoucangetupandinterruptthissedentarybehavior，thebetter.”
FiguresfromaU．S.surveyin20032004foundAmericansspendmorethanhalftheirtimesitting，fromworkingattheirdeskstosittingincars.
Expertssaidmoreresearchisneededtofigureoutjusthowmuchsittingisdangerous，andwhatmightbepossibletooffsetthoseeffects.
“Peopleshouldkeepexercisingbecauset
