还剩4页未读,继续阅读
文本内容:
Almostanyamountandtypeofphysicalactivity__yslowagingdeepwithinour__llsanewstudyfinds.Andmiddleage__ybeacriticaltimetogetthepro__ssrollingatleastbyonecommonmeasureof__llaging.一项新研究发现,不论运动量如何,几乎所有种类的体育活动都能延缓深藏于我们细胞内部的衰老过程而中年可能是让这一机制继续运行下去的关键时段,至少,就衡量细胞衰老的一个常用指标而言确是如此Datinga__ll’sageistrickybecauseitsbiologicalandchronologicalagesrarely__tch.A__llcouldberelativelyyoungintermsofhowlongithasexistedbutfunctionslowlyorerraticallyasifelderly.确定细胞的年龄可是个棘手差事,因为它们的生物学年龄(表明其__结构和生理功能的状态)和实际年龄基本上对不上号有些细胞论其存在时间可能还算年轻,但它们执行起生理机能来却十分缓慢或者不稳定,就如同衰老的细胞一样Today__nyscientistshavebegundetermininga__ll’sbiologicalage—meaninghowwellitfunctionsandnothowolditliterallyis—bymeasuringthelengthofitstelomeres.如今,许多科学家开始通过测量细胞的端粒长度来确定它的生物学年龄Forthoseofuswhodon’tknoweveryportionofour__lls’interiorstelomeresaretinycapsfoundontheendofDNAstrandslikeplasticagletsonshoela__s.TheyarebelievedtoprotecttheDNAfromda__geduring__lldivisionandreplication.我们中的一些人对细胞内部的各个结构并不都那么了如指掌,那么,打个比方来解释一下,端粒是DNA链末端的小帽子,就像鞋带上的塑料箍一样科学家们认为,它们可以防止DNA在细胞__和DNA__过程中受到损伤Asa__llagesitstelomeresnaturallyshortenandfray.Butthepro__sscanbeac__leratedbyobesity__okinginsomniadiabetesandotheraspectsofhealthandlifestyle.随着细胞的衰老,其端粒自然也会磨损和缩短但这一过程可能会因肥胖、吸烟、失眠、糖尿病等健康和生活方式问题而加快Inthosecasestheaffected__llsagepre__turely.在这种情况下,受影响的细胞就会过早衰老Howeverre__ntscien__suggeststhatexercise__yslowthefrayingoftelomeres.Paststu___shavefoundforinstan__that__sterathletestypicallyhavelongertelomeresthansedentarypeopleofthesameageasdoolderwomenwhofrequentlywalkorengageinotherfairlymoderateexercise.然而,最近的科学研究表明,锻炼身体可以减缓端粒的磨损例如,既往的研究发现,运动健将们的端粒通常比同龄的久坐者更长,在经常步行或从事其他适度运动的老年妇女中也有同样的现象Butthosestu___swererelativelynarrowfocusingmostlyonelderlypeoplewhoranorwalked.Itre__inedunclearwhetherpeopleofdifferentageswhoengagedinavarietyofexerciseswouldlikewiseshoweffectsontheirtelomeres.但是,这些研究的面相对较窄,主要集中在经常跑步或步行的老年人身上目前尚不清楚在不同年龄段的人群当中,从事多种运动是否也会对他们的端粒造成影响SoforthenewstudywhichwaspublishedthismonthinMedicineScien__inSportsExerciseresearchersfromtheUniversityofMississippiandUniversityofCaliforniaSanFranciscodecidedtolookmorebroadlyattheinteractionsofexerciseandtelomeresamongawideswathofAmericans.于是,在这项10月发表在《运动与锻炼中的医学与科学》__MedicineScien__inSportsExercise上的新研究中,来自密西西比大学UniversityofMississippi和加州大学旧金山分校UniversityofCaliforniaSanFrancisco的研究人员们决定在广大的美国人群中更广泛地探讨一下运动与端粒之间的相互作用TodosotheyturnedtotheimmensetroveofdatageneratedbytheongoingNationalHealthandNutritionExaminationSurveyforwhichtensofthousandsof_____sanswerquestionsannuallyabouttheirhealthincludingtheirexercisehabitsandcompleteanin-personhealthexamprovidingabloodsample.为此,他们把目光转向了正在进行的美国健康与营养调查NationalHealthandNutritionExaminationSurvey所产生的巨大的数据宝库在这项调查中,成千上万的成年人每年都会回答有关他们自己的健康状况(包括运动习惯)的问题,接受体检,并提供血液样本Inre__ntyearsthosebloodsampleshavebeentestedforamongother__rkersofhealthtelomerelengthintheparticipants’whiteblood__lls.近年来,研究人员对这些血样进行了化验,检测了参与者白细胞的端粒长度等多种健康标志物Theresearchersgatheredthedataforabout6500oftheparticipantsranginginagefrom20to84andthencategorizedthemintofourgroupsbasedonhowtheyhadrespondedtoquestionsaboutexercise研究人员收集了约6500名年龄在20岁到84岁的参与者的数据,然后根据他们对运动相关问题的回答,把他们分为四组Thosequestionsinthissurveytendedtobebroadaskingpeopleonlyifatanytimeduringthepastmonththeyhadengagedinweighttrainingmoderateexerciselikewalkingmorevigorousexerciselikerunningorhavewalkedorriddenabiketoworkorschool.这项调查只是笼统地询问了受访者在过去的一个月里是否曾进行过任何负荷训练、或步行等中等强度的运动、或跑步等较为剧烈的运动,又或者曾步行或骑自行车上班或上学Ifaparticipantansweredyestoanyofthosefourquestionsheorsheearnedapointfromtheresearchers.Sosomeonewhoreportedwalkingre__ivedapoint.Ifhealsoranheearnedanotherandsoonfora__ximumoffourpoints.在上述四个问题中,参与者的每一个肯定回答都会被研究人员计一分因此,报告曾经步行过的人可以得一分如果他还跑步了,就能再得一分,依此类推,最多可以得四分Theresearchersthencomparedthosetalliestoeachperson’stelomerelength.然后,研究人员比较了这些人的端粒长度及其得分Andtherewereclearassociations.Foreverypointsomeonegainedfromanytypeofexercisehisorherrisksofhavingunusuallyshorttelomeresdeclinedsignificantly.结果发现其间存在明显的相关性无论受访者从事了何种类型的运动,他每得一分,端粒长度异常缩短的风险都会显著下降Specificallysomeonewhoparticipatedinasingleactivityearningthema1wasabout3per__ntlesslikelytohaveveryshorttelomeresthansomeonewhodidn’texerciseatall具体而言,如果某人因为参加某一运动而赢得1分,他的端粒特别短的可能性就会比不锻炼的人低3%左右Thatriskdeclinedmoresubstantiallyifsomeoneexercisedmore.Peoplewhoreportedtwotypesofexercisewere24per__ntlesslikelytohaveshorttelomeres;threetypesofexercisewere29per__ntlesslikely;andthosewhohadparticipatedinallfourtypesofactivitieswere59per__ntlesslikelytohaveveryshorttelomeres.一个人锻炼得越多,这种风险下降的幅度就越大报告从事两种运动的人端粒特别短的可能性要降低24%;从事三种运动的人风险降低29%;参与了所有四种运动的人风险降低59%Interestinglytheseassociationswerestrongestamongpeoplebetweentheagesof40and65theresearchersfoundsuggestingthatmiddleage__ybeakeytimetobeginor__intainanexerciseprogramifyouwishtokeeptelomeresfromshrinkingsaysPaulLoprinzianassistantprofessorofhealthandexercisescien__attheUniversityofMississippi.Hewasaco-authorofthestudywithJeremyLoennekealsooftheUniversityofMississippiandElizabethBlackburnaprofessorattheUniversityofCaliforniaSanFranciscowhosharedaNobelPrizein2009forthediscoveryofthemolecularnatureoftelomeres.有趣的是,研究人员发现,这种相关性在40岁至65岁人群中最强密西西比大学的健康与运动科学助理教授保罗·罗普林茨PaulLoprinzi认为,这表明,要是你不想让端粒缩短,中年可能是开始或者坚持锻炼计划的关键时段他与密西西比大学的杰里米·伦内克JeremyLoenneke、加州大学旧金山分校UniversityofCaliforniaSanFrancisco的伊丽莎白·布莱克本ElizabethBlackburn教授同为本研究的共同__,而布莱克本教授曾因发现了端粒的分子性质而与其他人__了2009年的诺贝尔奖HoweverasDr.Loprinzipointsoutthisstudyispurelyassociationalsocannotshowwhetherexerciseactuallycauseschangesintelomerelengthonlythatpeoplewhoexercisehavelongertelomeres.然而,正如罗普林茨__指出的那样,这项研究只是个纯粹的相关性研究,所以它只表示锻炼的人端粒较长,却无法说明运动是否确实会导致端粒长度的变化Thestudyalsocouldn’tteaseouttheidealamountofexercisefortelomere__intenan__Dr.Loprinzisaybecausethesurveyaskedonlywhethersomeoneexercisedatallnothowfrequently.罗普林茨__还说,由于调查只询问了受访者是否进行过锻炼,并没有问及锻炼的频率,所以这项研究无法确定要维持端粒长度所需的理想运动量Perhapsmostimportanttheresultsdon’t____uswhetherlongertelomerestranslateintobetterhealth.ButDr.Loprinzisaysotherstu___sincludingfromhislab“haveshownthattelomeresarepredictiveofmortality”withshortertelomeresequatingtoshorterlives.也许最重要的是,研究结果并没能告诉我们,端粒较长是否就代表着更加健康但是,罗普林茨__表示,包括他自己实验室的在内的其他研究“显示,端粒对死亡有预测意义”,较短的端粒就等同于较短的寿命Sothemessageseemsclearhesays.“Exerciseisgood”foryour__llsand“moreexerciseingreatervariety”islikelytobeevenbetter.因此,个中启示很明确,他说,“运动对你的细胞有益”,且“越多地进行多种锻炼”效果可能就越好。