1.肌肉活動減少

　　造成失重時的肌肉萎縮的主要原因是失重時重力消失引起肌肉的“廢用性”變(bian)化(hua)，也(ye)就(jiu)是(shi)說(shuo)是(shi)因(yin)為(wei)長(chang)時(shi)間(jian)的(de)肌(ji)肉(rou)運(yun)動(dong)減(jian)少(shao)引(yin)起(qi)的(de)。因(yin)失(shi)重(zhong)時(shi)一(yi)切(qie)物(wu)體(ti)沒(mei)有(you)重(zhong)量(liang)
，肌(ji)肉(rou)不(bu)需(xu)要(yao)克(ke)服(fu)這(zhe)些(xie)重(zhong)量(liang)而(er)作(zuo)功(gong)，於(yu)是(shi)肌(ji)肉(rou)的(de)功(gong)能(neng)就(jiu)逐(zhu)漸(jian)退(tui)化(hua)，這(zhe)與(yu)長(chang)期(qi)躺(tang)在(zai)床(chuang)上(shang)的(de)人(ren)肌(ji)肉(rou)變(bian)得(de)無(wu)力(li)、萎縮是類同的。前蘇聯和美國在地麵上進行了大量的實驗，例如，前蘇聯選了一批誌願者，讓他們在床上躺49天。在實驗前與臥床第30tian，yonghuojianfangfacongbeishizhedebimuyujizhongquchuyixiaokuaijiroujinxingxingtaixueguancha，jieguofaxianwochuanghoujirouchuxianleyuhangtianzhongxiangsideweisuoxingbianhua。wochuangshirenrengshenghuozaizhonglihuanjingzhong，zhishijianshaolerendehuodong
，zhezhongqingkuangxiachuxianjirouweisuo，shuomingshizhongqingkuangxiahuodongdejianshaoshiyinqijirouweisuodezuizhuyaoyuanyin。kefujirouweisuodezuihaobanfashiqiangpotaduanlian，xianzaihangtianzhongsuocaiyongdefangzhijirouweisuodezuiyouxiaofangfajiushiyundong，hangtianyuanzaifeixingzhongmeitianyaojinxing2～3小時的運動
，運動項目包括拉力器、跑台
、自zi行xing車che功gong量liang計ji等deng。這zhe些xie方fang法fa對dui於yu防fang止zhi航hang天tian員yuan長chang期qi飛fei行xing時shi的de肌ji肉rou萎wei縮suo和he肌ji肉rou工gong作zuo能neng力li的de下xia降jiang起qi到dao有you利li的de作zuo用yong

，但dan還hai沒mei有you完wan全quan防fang止zhi失shi重zhong引yin起qi的de肌ji肉rou係xi統tong的de變bian化hua。因yin此ci，防fang止zhi失shi重zhong引yin起qi的de肌ji肉rou變bian化hua是shi航hang天tian醫yi學xue研yan究jiu的de重zhong要yao課ke題ti之zhi一yi。

　　2.血液循環係統的紊亂

　　肌ji肉rou內nei有you豐feng富fu的de血xue管guan，它ta是shi保bao證zheng肌ji肉rou正zheng常chang代dai謝xie和he收shou縮suo的de必bi要yao條tiao件jian。失shi重zhong可ke以yi影ying響xiang血xue液ye循xun環huan係xi統tong
，使shi血xue液ye循xun環huan係xi統tong出chu現xian紊wen亂luan，如ru出chu現xian下xia肢zhi肌ji肉rou血xue液ye供gong應ying減jian少shao，血xue粘zhan度du增zeng高gao，血xue管guan的de結jie構gou和he形xing態tai發fa生sheng改gai變bian。這zhe些xie都dou可ke影ying響xiang肌ji肉rou的de血xue液ye供gong應ying。

　　3.營養不足

　　youyugongchengshangdexianzhiheshizhongdeteshuhuanjing，hangtianyuanzaifeixingzhongbunengxiangzaidimianyiyangdedaofengfudeshipinhegezhongmeiweikekoudefancai。tongshi
，shizhonggaibianhangtianyuandeweijiao
，shihangtianyuanzaichirenheshiwushidougandaodanerwuweijihangtianchuqichuxiandeyundongbingzhengzhuang，zhexiedoujiangdilehangtianyuandeshiyu，shihangtianyuanchuxianleyingyangbuzu。shiwushigongyingjiroudanbaizhihechengdeyuanquan，hangtianyuanfeixingzhongshiyudejiangdi

，shiwusheruliangdebuzu，yeshizaochengjirouweisuodeyuanyinzhiyi。

　　由you上shang可ke見jian，失shi重zhong對dui骨gu骼ge肌ji是shi有you明ming顯xian影ying響xiang的de，隨sui著zhe飛fei行xing時shi間jian的de延yan長chang，對dui肌ji肉rou的de影ying響xiang將jiang更geng嚴yan重zhong。因yin此ci
，研yan究jiu失shi重zhong對dui肌ji肉rou係xi統tong的de影ying響xiang，尋xun找zhao有you效xiao的de防fang護hu措cuo施shi是shi航hang天tian醫yi學xue研yan究jiu的de十shi分fen主zhu要yao的de課ke題ti。

轉    自：中國空間技術研究院

本文編輯：李遷