翻譯:徐金成高璨審校:趙杰修
1國(guó)家體育總局體育科學(xué)研究所運(yùn)動(dòng)生物科學(xué)中心(北京100061)
2國(guó)家體育總局運(yùn)動(dòng)醫(yī)學(xué)研究所(北京100061)
高溫環(huán)境中訓(xùn)練和比賽的共識(shí)性建議
翻譯:徐金成1高璨2審校:趙杰修1
1國(guó)家體育總局體育科學(xué)研究所運(yùn)動(dòng)生物科學(xué)中心(北京100061)
2國(guó)家體育總局運(yùn)動(dòng)醫(yī)學(xué)研究所(北京100061)
譯文通信作者:趙杰修,Email:zhaojiexiu1@163.com
高溫環(huán)境中運(yùn)動(dòng)會(huì)引起體溫調(diào)節(jié)和其它生理壓力,繼而可導(dǎo)致耐力運(yùn)動(dòng)能力的損害。本共識(shí)性聲明的目的是提供最新的建議以使熱環(huán)境中體育活動(dòng)時(shí)的運(yùn)動(dòng)能力最優(yōu)化??捎糜诮档蜔釕?yīng)激壓力和優(yōu)化運(yùn)動(dòng)能力的最重要干預(yù)方式是熱習(xí)服,其應(yīng)包括1~2周以上反復(fù)的運(yùn)動(dòng)—高溫環(huán)境暴露。此外,運(yùn)動(dòng)員應(yīng)在正常水合狀態(tài)下開始比賽和訓(xùn)練,并將運(yùn)動(dòng)中的脫水最小化。隨著商用降溫系統(tǒng)(如降溫背心)的發(fā)展,在高溫環(huán)境中訓(xùn)練或比賽前,運(yùn)動(dòng)員可以采取降溫策略來促進(jìn)熱的散發(fā)或提高蓄熱能力。而且,賽事組織者應(yīng)該設(shè)計(jì)大面積的遮陽區(qū)域,并提供降溫和補(bǔ)水設(shè)施,按照最小化運(yùn)動(dòng)員的健康風(fēng)險(xiǎn)來安排賽事,尤其是在大眾參與的賽事中及一年之中炎熱天氣開始之初。以最近的2008年奧運(yùn)會(huì)和2014年國(guó)際足聯(lián)世界杯為例,當(dāng)比賽在高溫環(huán)境中舉行時(shí),賽事主管機(jī)構(gòu)應(yīng)考慮在比賽中或比賽之間允許額外的(或更長(zhǎng)的)恢復(fù)期以提供補(bǔ)水和降溫的時(shí)機(jī)。
大多數(shù)重要的國(guó)際性賽事,例如夏季奧運(yùn)會(huì)、國(guó)家足聯(lián)世界杯和環(huán)法自行車賽——以電視觀眾而言,也是世界范圍內(nèi)最受歡迎的三項(xiàng)賽事——均在北半球的夏季月份舉行,通常也是在熱環(huán)境中進(jìn)行。2014年3月23日、24日,在卡塔爾多哈ASPETAR骨科與運(yùn)動(dòng)醫(yī)學(xué)醫(yī)院舉辦的一個(gè)主題會(huì)議上,專家小組回顧和討論了“高溫環(huán)境中訓(xùn)練和比賽”這個(gè)專題。會(huì)議以圓桌討論的形式結(jié)束,并達(dá)成了本共識(shí)性建議。
本文旨在為熱環(huán)境中運(yùn)動(dòng)時(shí)的運(yùn)動(dòng)能力最佳化提供最新的建議。熱環(huán)境中運(yùn)動(dòng)時(shí),考慮到短時(shí)運(yùn)動(dòng)能力(如跳躍和沖刺)僅受到最輕微的影響,或甚至還能得到提高[1],但長(zhǎng)時(shí)間運(yùn)動(dòng)能力顯著受損[2],因此本共識(shí)性聲明中的建議主要針對(duì)長(zhǎng)時(shí)類運(yùn)動(dòng)項(xiàng)目。有關(guān)“高溫環(huán)境中訓(xùn)練和比賽”的更多信息,讀者可在《斯堪的納維亞運(yùn)動(dòng)醫(yī)學(xué)與科學(xué)雜志》(Scandinavian Journal of Medicine and Science in Sports)的??汐@取,包括針對(duì)性綜述和原創(chuàng)性研究[3]。
高溫環(huán)境中運(yùn)動(dòng)時(shí),皮膚血流量和出汗率增加以利于機(jī)體向周圍環(huán)境散熱。但是,這些體溫調(diào)節(jié)的調(diào)整會(huì)增加生理壓力,可能會(huì)導(dǎo)致長(zhǎng)時(shí)間運(yùn)動(dòng)時(shí)的脫水。當(dāng)體溫過高發(fā)生時(shí),熱應(yīng)激可單獨(dú)損害有氧運(yùn)動(dòng)能力[2,4-6]。因此,高溫環(huán)境中運(yùn)動(dòng)時(shí),運(yùn)動(dòng)員從事耐力性項(xiàng)目、持拍類項(xiàng)目及團(tuán)隊(duì)項(xiàng)目的工作效率較溫和環(huán)境中低[7-12]。此外,高溫環(huán)境運(yùn)動(dòng)中的脫水加劇了熱調(diào)節(jié)和心血管壓力[13-18],并進(jìn)一步損害有氧運(yùn)動(dòng)能力[2,17,19]。本文中所含建議和策略可被用于維持/改善高溫環(huán)境中訓(xùn)練和比賽時(shí)的運(yùn)動(dòng)能力,也可以使運(yùn)動(dòng)性中暑(Exertional heat illness)的風(fēng)險(xiǎn)最小化。如本文第1部分所述,能用于降低生理壓力和優(yōu)化運(yùn)動(dòng)能力的最重要干預(yù)方式是熱習(xí)服??紤]到脫水可損害運(yùn)動(dòng)能力及加劇運(yùn)動(dòng)性熱應(yīng)激壓力,本共識(shí)性聲明的第2部分提供了關(guān)于補(bǔ)水的建議。第3部分強(qiáng)調(diào)了通過皮膚降溫服裝,如冰袋、冷毛巾、降溫背心,以及冷水浸泡(Cold water immersion,CWI)或冰漿飲料的應(yīng)用,在運(yùn)動(dòng)前或運(yùn)動(dòng)中可能降低核心和皮膚溫度的方法。
考慮到缺乏實(shí)際比賽中的數(shù)據(jù),國(guó)際奧委會(huì)(IOC)強(qiáng)調(diào)了各專項(xiàng)運(yùn)動(dòng)協(xié)會(huì)、隊(duì)醫(yī)和科研工作者共同合作收集優(yōu)秀運(yùn)動(dòng)員這一特定人群在具有挑戰(zhàn)性環(huán)境中運(yùn)動(dòng)時(shí)數(shù)據(jù)的必要性[20]。有幾個(gè)國(guó)際性運(yùn)動(dòng)協(xié)會(huì),如國(guó)際足聯(lián)(FIFA)、國(guó)際泳聯(lián)(FINA)、國(guó)際排聯(lián)(FIVB)、國(guó)際田聯(lián)(IAAF)和國(guó)際網(wǎng)聯(lián)(ITF),已經(jīng)啟用監(jiān)控系統(tǒng)評(píng)估比賽時(shí)的環(huán)境條件及相關(guān)不良后果,開展這項(xiàng)具有挑戰(zhàn)性的工作[12,21-23]。許多運(yùn)動(dòng)協(xié)會(huì)也已修改了他們的指導(dǎo)原則以進(jìn)一步降低運(yùn)動(dòng)性中暑的風(fēng)險(xiǎn)。這些指導(dǎo)原則在本共識(shí)性建議的第4部分進(jìn)行了綜述。本文還針對(duì)在高溫環(huán)境中賽事期間如何最好地保護(hù)運(yùn)動(dòng)員的健康和維持/改善運(yùn)動(dòng)能力,向賽事組織者和運(yùn)動(dòng)主管機(jī)構(gòu)提供了建議。
盡管溫和環(huán)境中的規(guī)律運(yùn)動(dòng)會(huì)引發(fā)部分的熱習(xí)服[24],但其并不能取代高溫環(huán)境中連續(xù)多日訓(xùn)練所引發(fā)的效益[24-27]。熱習(xí)服可改善溫?zé)釛l件下的熱舒適感與次最大和最大強(qiáng)度下的有氧運(yùn)動(dòng)能力[11,28,29]。熱習(xí)服的益處通過以下途徑獲得:增加汗液分泌和皮膚血流反應(yīng),血漿容量擴(kuò)張從而改善心血管功能穩(wěn)定性(即維持血壓和心輸出量的能力更佳)和體液—電解質(zhì)平衡[19,30,31]。因此,運(yùn)動(dòng)性熱習(xí)服對(duì)于備戰(zhàn)溫?zé)岘h(huán)境中比賽的運(yùn)動(dòng)員來說是必不可少的[30]。本部分描述了如何實(shí)施熱習(xí)服方案和使其對(duì)運(yùn)動(dòng)員的效益最優(yōu)化。
3.1熱習(xí)服的誘導(dǎo)
3.1.1持續(xù)時(shí)間
大多數(shù)適應(yīng)性改變(即心率、皮膚和肛門溫度的降低,出汗率和工作能力的提高)在熱習(xí)服的第1周內(nèi)發(fā)生,在隨后2周內(nèi)進(jìn)展較為緩慢[32-34]。與未經(jīng)訓(xùn)練的個(gè)體相比,這些適應(yīng)性變化在訓(xùn)練有素的運(yùn)動(dòng)員中發(fā)展更為迅速(時(shí)間可相當(dāng)于前者的一半)[24,35]。因此,運(yùn)動(dòng)員在熱習(xí)服的前幾天即可受益[36-38],但需要6~10天才能獲得近乎完整的心血管和泌汗運(yùn)動(dòng)神經(jīng)的適應(yīng)性變化[28,29,39],因而需要2周才能使熱環(huán)境中的有氧運(yùn)動(dòng)能力(即自行車計(jì)時(shí)測(cè)試)最優(yōu)化[11]。
3.1.2訓(xùn)練
任何熱習(xí)服方案的根本原理是體溫(核心和皮膚)的升高以誘導(dǎo)大量出汗和增加皮膚血流量[19,30]。最初,研究顯示高溫環(huán)境中反復(fù)的100米運(yùn)動(dòng)訓(xùn)練有效誘導(dǎo)了上述反應(yīng)[40]。另據(jù)報(bào)道,熱環(huán)境中(40℃,10%RH)每天以60%最大攝氧量(VO2max)強(qiáng)度運(yùn)動(dòng)到力竭,持續(xù)9-12天,可將運(yùn)動(dòng)能力從48 min提升到80 min[28]。適應(yīng)性變化的幅度最終取決于強(qiáng)度、持續(xù)時(shí)間、頻率和熱暴露的次數(shù)[30,31]。例如,Houmard等[41]報(bào)道中等強(qiáng)度短時(shí)間(30-35 min,75%VO2max)和低強(qiáng)度長(zhǎng)時(shí)間(60 min,50%VO2max)運(yùn)動(dòng)后出現(xiàn)了相似的生理適應(yīng)性變化。
隨著熱習(xí)服的進(jìn)展,恒定負(fù)荷的運(yùn)動(dòng)方案可能導(dǎo)致一個(gè)逐漸降低的訓(xùn)練刺激(即相對(duì)運(yùn)動(dòng)強(qiáng)度的減小)。相應(yīng)地,如果高溫環(huán)境中運(yùn)動(dòng)訓(xùn)練課的持續(xù)時(shí)間和/或強(qiáng)度不對(duì)應(yīng)增加,就可能會(huì)限制適應(yīng)性變化的幅度[42]。在可能的情況下,可采用等溫方案(例如核心溫度至少在38.5℃的受控高體溫)以使適應(yīng)性變化最優(yōu)化[43,44]。盡管如此,等溫方案可能需要更強(qiáng)的控制及使用人工實(shí)驗(yàn)室條件,因此可能會(huì)限制其在場(chǎng)地中的實(shí)用性?;蛘?,最近有人提出利用基于心率的受控強(qiáng)度方案來實(shí)現(xiàn)習(xí)服過程中增加絕對(duì)強(qiáng)度和維持相似相對(duì)強(qiáng)度的需求[31]。最后,運(yùn)動(dòng)員可通過高溫環(huán)境中的戶外訓(xùn)練進(jìn)行適應(yīng)(即習(xí)服),可以是自我調(diào)控的運(yùn)動(dòng)或維持原有的常規(guī)訓(xùn)練方案。該練習(xí)的功效已在團(tuán)隊(duì)項(xiàng)目運(yùn)動(dòng)員中得到證實(shí)[45,46],且不會(huì)干擾他們的訓(xùn)練方案。
3.1.3環(huán)境
干熱環(huán)境中的熱習(xí)服可改善濕熱環(huán)境中的運(yùn)動(dòng)能力[48,49],反之亦然[49]。但是,濕熱環(huán)境中的習(xí)服較干熱環(huán)境產(chǎn)生更高的皮膚溫度和循環(huán)適應(yīng),可能增加最大皮膚濕潤(rùn)度,因此增大從皮膚蒸發(fā)性散熱的最大速率[30,31,50]。盡管該做法依然缺乏科學(xué)支持,但是在干熱環(huán)境中熱習(xí)服訓(xùn)練的末期讓運(yùn)動(dòng)員轉(zhuǎn)移到濕熱環(huán)境中進(jìn)行訓(xùn)練,進(jìn)一步刺激心血管和體溫調(diào)節(jié)系統(tǒng),對(duì)于運(yùn)動(dòng)員來說可能是有益的。然而,盡管不同環(huán)境中的習(xí)服存在遷移效應(yīng),但有些適應(yīng)性變化是特定于氣候(沙漠或熱帶)和體力活動(dòng)水平的[51]。因此,建議運(yùn)動(dòng)員主要針對(duì)即將比賽的環(huán)境進(jìn)行習(xí)服。
不能到自然熱環(huán)境中(所謂的自然氣候習(xí)服(Acclimatisation))的運(yùn)動(dòng)員可以在人工室內(nèi)熱環(huán)境中進(jìn)行訓(xùn)練習(xí)服(所謂的實(shí)驗(yàn)室習(xí)服(Acclimation))。然而,雖然實(shí)驗(yàn)室習(xí)服和自然氣候習(xí)服有相似的生理適應(yīng)性變化,但戶外訓(xùn)練對(duì)于比賽環(huán)境更具特異性,因?yàn)樗梢宰屵\(yùn)動(dòng)員體驗(yàn)到熱應(yīng)激的實(shí)質(zhì)[52-54]。
3.2短期熱習(xí)服的衰退和周期
熱適應(yīng)以不同的速度衰退,最快的適應(yīng)性變化衰退也更快[35]。然而,熱習(xí)服的衰退速率通常是慢于其誘導(dǎo)速率的,這就允許熱習(xí)服的大多數(shù)效益(例如心率、核心溫度)可維持2~4周[34,55-58]。而且在此期間,個(gè)體的再習(xí)服要快于第一個(gè)習(xí)服期[57](表1)。但是這些研究主要基于熱習(xí)服的生理指標(biāo),競(jìng)賽運(yùn)動(dòng)能力的衰退仍有待進(jìn)一步的闡釋。
表1 熱習(xí)服策略示例
3.3個(gè)體化熱習(xí)服
熱習(xí)服可明顯減弱生理應(yīng)激壓力[59,60]。然而,個(gè)體的習(xí)服反應(yīng)可能有所不同,因此應(yīng)該使用一些簡(jiǎn)易的指標(biāo)進(jìn)行監(jiān)控,例如標(biāo)準(zhǔn)次最大強(qiáng)度運(yùn)動(dòng)時(shí)心率增加幅度的減少[33,61-63]。監(jiān)控?zé)崃?xí)服的其它較難與較不敏感指標(biāo)包括出汗率和鈉含量[64],核心溫度[33]和血漿容量[65]。熱習(xí)服中,血漿容量擴(kuò)張的作用仍然存在爭(zhēng)議,因?yàn)槿藶榈卦黾友獫{容量似乎并沒有改善體溫調(diào)節(jié)能力[66,67],但是在短期熱習(xí)服之后的熱應(yīng)激反應(yīng)測(cè)試中,紅細(xì)胞壓積(Hct)的變化與個(gè)體運(yùn)動(dòng)能力相關(guān)[45,46]。這就提示血漿容量變化可能代表了一個(gè)有價(jià)值的指標(biāo),即使其可能并非是改善高溫環(huán)境中運(yùn)動(dòng)能力的生理機(jī)制。重要的是,適宜溫和環(huán)境中的測(cè)量方法并不能用于替代熱環(huán)境中的測(cè)試[45,46,68]。
如同熱習(xí)服的誘導(dǎo)一樣,熱習(xí)服的衰減在不同個(gè)體間也存在差異[32]。因此,我們建議運(yùn)動(dòng)員在重大高溫賽事前數(shù)月進(jìn)行一個(gè)習(xí)服練習(xí)以確定他們個(gè)體化的適應(yīng)與衰減速率[20,45](表1)。
3.4熱習(xí)服作為訓(xùn)練刺激
最近幾項(xiàng)實(shí)驗(yàn)室或未加環(huán)境控制的場(chǎng)地研究已報(bào)告指出適宜溫和環(huán)境中的身體運(yùn)動(dòng)能力在高溫環(huán)境中訓(xùn)練后得到改善[29,46,62,69,70]。因此,賽季前和賽季中,運(yùn)動(dòng)員可考慮采用熱環(huán)境中的集訓(xùn)來改善身體運(yùn)動(dòng)能力[46](表1)。需要謹(jǐn)記的是,訓(xùn)練質(zhì)量不應(yīng)該被損害,從中獲益最多的運(yùn)動(dòng)員可能是那些需要新異訓(xùn)練刺激的有經(jīng)驗(yàn)的運(yùn)動(dòng)員[46],而對(duì)于訓(xùn)練有素而又需有限體溫調(diào)節(jié)需求(如冷環(huán)境中的自行車運(yùn)動(dòng))的運(yùn)動(dòng)員來說,益處可能更多地視情況而定[71]。
3.5熱習(xí)服主要建議的總結(jié)
—計(jì)劃到熱環(huán)境中進(jìn)行比賽的運(yùn)動(dòng)員應(yīng)進(jìn)行熱習(xí)服(即高溫環(huán)境中的反復(fù)訓(xùn)練)以獲得生物適應(yīng)性變化,繼而降低高溫環(huán)境中的生理應(yīng)激壓力和改善高溫環(huán)境中的運(yùn)動(dòng)能力。
—熱習(xí)服訓(xùn)練課應(yīng)持續(xù)至少60分鐘/天,應(yīng)誘導(dǎo)核心和皮膚溫度的升高,還應(yīng)刺激出汗。
—運(yùn)動(dòng)員應(yīng)在與比賽場(chǎng)地相同的環(huán)境中進(jìn)行訓(xùn)練,或如不可能的話,則應(yīng)在室內(nèi)熱環(huán)境房?jī)?nèi)進(jìn)行訓(xùn)練。
—早期適應(yīng)性變化在最初幾天即可獲得,但是主要的生理適應(yīng)性變化直到1周后才能完整獲得。理想條件下,為了最大化所有的效益,熱習(xí)服階段應(yīng)超過2周。
熱環(huán)境中運(yùn)動(dòng)時(shí),體溫過高的發(fā)展與出汗率的升高有關(guān),如果體液的丟失未通過增加液體攝入而最小化,則可導(dǎo)致漸進(jìn)性脫水。運(yùn)動(dòng)性脫水,導(dǎo)致機(jī)體處于缺水狀態(tài),與血漿容量的降低和血漿滲透壓的升高相關(guān),后兩者與體內(nèi)總水分含量的降低成比例[19]。血管舒張相關(guān)核心體溫閾值的升高和運(yùn)動(dòng)起始的排汗與隨后產(chǎn)生的高滲透壓和血容量過低緊密聯(lián)系在一起[72,73]。運(yùn)動(dòng)時(shí),血漿高滲會(huì)降低任何給定核心體溫的出汗率,減少蒸發(fā)散熱[74]。此外,脫水還會(huì)減少心臟充盈,給血壓調(diào)節(jié)帶來挑戰(zhàn)[75-77]。因此,機(jī)體的熱蓄積率和心血管壓力加劇,高溫環(huán)境中的運(yùn)動(dòng)耐受能力則降低[78-80]。
盡管該領(lǐng)域的研究已有數(shù)十年[81],脫水損害競(jìng)技運(yùn)動(dòng)中有氧能力這一觀點(diǎn)并未得到普遍接受,似乎存在一個(gè)兩極化的爭(zhēng)議[82-84]。大量研究報(bào)告指出如果運(yùn)動(dòng)是在溫?zé)岘h(huán)境中進(jìn)行且水分的缺失已至少超過體重的2%時(shí),脫水會(huì)損害該情況下的有氧運(yùn)動(dòng)能力[13,49,81,85-90]。另一方面,一些最近的研究認(rèn)為在真實(shí)自然生態(tài)條件下,達(dá)體重4%的脫水并未改變自行車運(yùn)動(dòng)表現(xiàn)[82,83,91]。然而,對(duì)上述研究結(jié)果的解讀必須結(jié)合研究背景:訓(xùn)練有素的自行車運(yùn)動(dòng)員是在高達(dá)33℃、60%RH的環(huán)境中通常進(jìn)行60 min運(yùn)動(dòng),且開始運(yùn)動(dòng)時(shí)身體處在水分充足狀態(tài)。盡管如此,還是有人提出了一個(gè)觀點(diǎn),即脫水的不良后果被運(yùn)動(dòng)飲料公司過分強(qiáng)調(diào)了[92]。正因如此,有人認(rèn)為應(yīng)根據(jù)口渴感飲水[82,83,91]。但是,許多研究(通常是在運(yùn)動(dòng)飲料被發(fā)明和市場(chǎng)化之前進(jìn)行)已經(jīng)反復(fù)觀察到當(dāng)出汗率高及在溫?zé)岘h(huán)境中運(yùn)動(dòng)時(shí),根據(jù)口渴感飲水往往導(dǎo)致機(jī)體水的缺失,其可能超過體重的2%~3%[13,47,49,93-98]??傊鶕?jù)口渴感飲水可能在很多環(huán)境中適用,但不適用于可預(yù)期到嚴(yán)重脫水的情況中(如鐵人三項(xiàng))[84]。
在比賽環(huán)境中,補(bǔ)水取決于幾個(gè)因素,包括液體的可獲得性和賽事的特異性。例如,由于比賽中暫停休息的頻次,網(wǎng)球運(yùn)動(dòng)員可定期補(bǔ)液,其它運(yùn)動(dòng)員,如馬拉松運(yùn)動(dòng)員,則只有較少的機(jī)會(huì)進(jìn)行補(bǔ)水。不同選手之間也存在區(qū)別。最快的馬拉松選手在比賽中不會(huì)攝取大量的液體及脫水,相反地,較慢的選手可能補(bǔ)水過度[99],且伴隨著水中毒(即低鈉血癥)的相關(guān)風(fēng)險(xiǎn)[100]。馬拉松比賽中產(chǎn)生低鈉血癥的相關(guān)易感因素包括體重大量增加、比賽時(shí)間長(zhǎng)于4小時(shí)、女性及低身體質(zhì)量指數(shù)(BMI)[101,102]。因此,盡管下文中針對(duì)競(jìng)技運(yùn)動(dòng)員的建議解釋了如何最小化與顯著脫水和體重丟失(即≥2%)相關(guān)的運(yùn)動(dòng)能力損害,但參加長(zhǎng)時(shí)間運(yùn)動(dòng)的業(yè)余運(yùn)動(dòng)員應(yīng)注意不要在運(yùn)動(dòng)中補(bǔ)水過度。
4.1運(yùn)動(dòng)前補(bǔ)水
靜止休息及營(yíng)養(yǎng)充足人群通常是處在充足水合狀態(tài),每日的身體總水分含量差異在體重的0.2%到0.7%之間波動(dòng)[93,104]。然而,當(dāng)比賽前幾天暴露于熱應(yīng)激條件下時(shí),提醒運(yùn)動(dòng)員充分地飲水和補(bǔ)充電解質(zhì)以確保身體充分水合狀態(tài)的維持可能是明智的。一般而言,在此期間每隔2~3小時(shí)或高溫環(huán)境中訓(xùn)練或比賽前2~3小時(shí),以每千克(kg)體重6毫升(mL)的量飲水是適當(dāng)?shù)摹?/p>
目前,有幾個(gè)方法可用于評(píng)測(cè)身體的水合狀態(tài),鑒于體液丟失的方式和時(shí)間,每個(gè)方法都有其局限性[105,106]。最被廣泛接受和推薦的方法包括監(jiān)控體重變化,測(cè)量血漿滲透壓和尿比重?;谶@些方法,如果每日體重變化維持在<1%、血漿滲透壓<290 mmol/kg及尿比重<1.020,即被認(rèn)為是正常水合狀態(tài)。這些技術(shù)方法可應(yīng)用于持續(xù)多天的間歇性賽事中(如自行車分段賽,網(wǎng)球/團(tuán)隊(duì)項(xiàng)目的錦標(biāo)賽),以監(jiān)控水合狀態(tài)。由于體重可能發(fā)生每日波動(dòng),設(shè)定基準(zhǔn)體重是重要的。基準(zhǔn)體重最好通過測(cè)量連續(xù)數(shù)日清晨排空后的裸體重來獲得,測(cè)試前一晚攝取1~2 L的液體[81]。此外,因?yàn)檫\(yùn)動(dòng)、飲食和早前的飲水會(huì)影響尿液濃度的測(cè)量,第一次晨尿是評(píng)價(jià)水合狀態(tài)的首選評(píng)定時(shí)間點(diǎn)[81]。如果不能獲取第一次晨尿,尿液采集前的數(shù)小時(shí)應(yīng)只有最小量的體力活動(dòng)、液體攝入和進(jìn)食。
4.2運(yùn)動(dòng)中補(bǔ)水
鑒于代謝速率、環(huán)境條件和熱習(xí)服狀態(tài),高溫環(huán)境中運(yùn)動(dòng)時(shí)的出汗率差異顯著[107]。雖然對(duì)于熱環(huán)境中進(jìn)行劇烈運(yùn)動(dòng)的運(yùn)動(dòng)員來說,范圍1.0 L/h-1.5 L/h的出汗率值是常見的,但是某些個(gè)體可超過2.5 L/h[108-111]。在過去的數(shù)十年中,不同的數(shù)學(xué)模型已被發(fā)展用于預(yù)測(cè)廣泛環(huán)境條件中的汗液丟失[112-117]。雖然其已被證明在公共健康、軍事、職業(yè)及運(yùn)動(dòng)醫(yī)學(xué)領(lǐng)域中是有用的,但是這些模型仍需進(jìn)一步的完善和針對(duì)運(yùn)動(dòng)員群體的個(gè)性化,尤其是優(yōu)秀運(yùn)動(dòng)員。
汗液中丟失的主要電解質(zhì)是鈉(20~70毫克當(dāng)量/升(mEq/L))[118-119],對(duì)于出汗嚴(yán)重且汗液中含較多鹽分的人,運(yùn)動(dòng)中需要進(jìn)行補(bǔ)充,以維持血漿中的鈉平衡。嚴(yán)重出汗者可能還需要在炎熱天氣中的訓(xùn)練和比賽前后注意增加鈉(即鹽分)的攝入量以維持鈉平衡(如在0.5 L糖-電解質(zhì)飲料中加入3.0 g的鹽)。為此,美國(guó)醫(yī)學(xué)研究所(Institute of Medicine)[103]已經(jīng)強(qiáng)調(diào)有關(guān)鈉攝入的公共健康建議不適用于汗液中丟失大量鈉的個(gè)體,如高溫環(huán)境中訓(xùn)練或比賽的運(yùn)動(dòng)員。鹽分的攝入如果不能代償汗液中鈉的丟失就會(huì)導(dǎo)致體內(nèi)鈉的缺失,鈉缺失達(dá)到體內(nèi)可交換性鈉鹽池的20%~30%時(shí),就可能導(dǎo)致肌肉痙攣[120]。因此,持續(xù)時(shí)間超過1小時(shí)的運(yùn)動(dòng)中,運(yùn)動(dòng)員應(yīng)力求攝入一份含0.5~0.7 g/L鈉的溶液[121-123]。對(duì)于出現(xiàn)肌肉痙攣的運(yùn)動(dòng)員,建議將液體中鈉的補(bǔ)充增加到1.5 g/L[124]。對(duì)于超過1小時(shí)的運(yùn)動(dòng),運(yùn)動(dòng)員在其補(bǔ)水方案中還應(yīng)力求包括30-60 g/h量的糖攝入;運(yùn)動(dòng)時(shí)間超過2.5小時(shí)的賽事,糖的攝入量可達(dá)90 g/h[125];上述建議可通過液體和固體食物的組合來實(shí)現(xiàn)。4.3運(yùn)動(dòng)后補(bǔ)水
高溫環(huán)境中訓(xùn)練或比賽后,水分的再補(bǔ)充對(duì)促進(jìn)優(yōu)化恢復(fù)尤為重要。如果體液的缺失迫切地需要得到補(bǔ)充,那么建議在運(yùn)動(dòng)停止后的1小時(shí)內(nèi)補(bǔ)充體重丟失量的150%[123,126],其中包含電解質(zhì)的補(bǔ)充,以維持體內(nèi)總水分含量。從實(shí)際角度來看,由于各種原因(例如時(shí)間、腸胃不適),上述建議并不是所有運(yùn)動(dòng)員都能實(shí)現(xiàn)的。因此,更實(shí)際的是補(bǔ)充體重丟失量的100%~120%。運(yùn)動(dòng)后補(bǔ)水的首選方式是通過液體和食物(例如咸食)的攝入。
考慮到高溫環(huán)境中運(yùn)動(dòng)會(huì)增加糖的代謝[127,128],耐力運(yùn)動(dòng)員應(yīng)確保不僅水和鈉的丟失得到補(bǔ)充,而且糖存儲(chǔ)也應(yīng)得到補(bǔ)充[129]。為確保肌肉糖原再合成的最高速率,糖的攝取應(yīng)該在運(yùn)動(dòng)結(jié)束后的1小時(shí)內(nèi)[130]。而且,含蛋白質(zhì)的飲品(例如牛奶)較標(biāo)準(zhǔn)的糖-電解質(zhì)運(yùn)動(dòng)飲料可能更好地實(shí)現(xiàn)運(yùn)動(dòng)后的體液平衡恢復(fù)[131]。有報(bào)告指出結(jié)合蛋白質(zhì)(0.2~0.4 g/kg/h)和糖(0.8 g/kg/h)的攝入可最大化蛋白質(zhì)的合成率[132]。因此,運(yùn)動(dòng)員在運(yùn)動(dòng)后應(yīng)該考慮攝取如巧克力牛奶樣的飲料,其含有4:1的糖-蛋白質(zhì)比例,同時(shí)還含有鈉[133]。
4.4補(bǔ)水主要建議的總結(jié)
—高溫環(huán)境中訓(xùn)練和比賽前,運(yùn)動(dòng)員應(yīng)每隔2~3小時(shí)以6 ml/kg體重的量飲水,以便開始運(yùn)動(dòng)時(shí)處在正常水合狀態(tài)。
—高溫環(huán)境中長(zhǎng)時(shí)間大強(qiáng)度運(yùn)動(dòng)時(shí),身體水分的丟失應(yīng)該被降低到最?。ú怀霈F(xiàn)體重增加)以降低生理應(yīng)激壓力及幫助維持最佳運(yùn)動(dòng)能力。
—高溫環(huán)境中訓(xùn)練的運(yùn)動(dòng)員較一般人群有更高的每日鈉(即鹽分)需求。運(yùn)動(dòng)中鈉的補(bǔ)充也可能是有必要的。
—對(duì)于持續(xù)多日的比賽(如自行車分段賽,網(wǎng)球/團(tuán)隊(duì)項(xiàng)目錦標(biāo)賽),簡(jiǎn)便的監(jiān)測(cè)方法,如監(jiān)測(cè)每日晨起體重和尿比重,可有助于深入了解運(yùn)動(dòng)員的每日水合狀態(tài)。
—通過提供充足的液體和食物來實(shí)現(xiàn)運(yùn)動(dòng)-高溫應(yīng)激后的充分補(bǔ)水是必要的。如果需要積極快速的補(bǔ)充,那么攝入液體和電解質(zhì)來補(bǔ)償體重丟失量的100%~150%就可實(shí)現(xiàn)充分補(bǔ)水。
—恢復(fù)性補(bǔ)水方案應(yīng)包含鈉、糖和蛋白質(zhì)。
皮膚降溫會(huì)降低高溫環(huán)境中運(yùn)動(dòng)時(shí)的心血管壓力,而全身降溫可降低器官和骨骼肌的溫度。數(shù)項(xiàng)在受控實(shí)驗(yàn)室條件下(如不可代償?shù)臒釕?yīng)激)的研究,運(yùn)動(dòng)中大多數(shù)伴隨或未伴隨降低通風(fēng)強(qiáng)度的情況,已報(bào)告指出預(yù)冷降溫可改善耐力[134-140]與高強(qiáng)度[141]及間歇沖刺或重復(fù)沖刺運(yùn)動(dòng)能力[142-145]。但是,其它幾個(gè)研究報(bào)告指出未見預(yù)冷降溫對(duì)高溫環(huán)境中間歇沖刺或重復(fù)沖刺運(yùn)動(dòng)能力的改善效益[142,146-148]。在單次沖刺或涉及重復(fù)沖刺運(yùn)動(dòng)的最初幾次練習(xí)中,全身降溫(包括運(yùn)動(dòng)肌的降溫)甚至不利于運(yùn)動(dòng)能力的發(fā)揮[149,150]。
因此,雖然數(shù)篇綜述得出降溫干預(yù)可延長(zhǎng)高溫環(huán)境中運(yùn)動(dòng)能力的結(jié)論[151-158],但必須承認(rèn),基于實(shí)驗(yàn)室的降溫干預(yù)研究與戶外空氣流動(dòng)的環(huán)境相比可能高估了預(yù)冷降溫的效應(yīng)[159],或者未考慮到賽前熱身的需求。因此,比賽環(huán)境中的降溫效應(yīng)依然是不清晰的,下文中的建議限于無氣流運(yùn)動(dòng)或有限氣流運(yùn)動(dòng)熱環(huán)境中的長(zhǎng)時(shí)間運(yùn)動(dòng)。
5.1冷水浸泡
有眾多的冷水浸泡(Cold water immersion,CWI)方案可以利用(綜述可見本文參考文獻(xiàn)[156,160-162]),但最常用的方法是在22~30℃水溫中全身CWI 30 min,或肢體節(jié)段(如腿部)在更低的水溫中(10~18℃)浸泡[156]。然而,腿部/肌肉的冷卻降溫會(huì)降低神經(jīng)傳導(dǎo)和肌肉收縮速度[1],因此運(yùn)動(dòng)員在比賽前可能需要再次熱身。所以,包含降溫服在內(nèi)的其它技術(shù)方法就被發(fā)展用于選擇性地對(duì)運(yùn)動(dòng)員軀干進(jìn)行降溫,這就可能防止活動(dòng)肌群的過度降溫,同時(shí)降低總熱應(yīng)激和心血管壓力。
5.2降溫服
在為實(shí)現(xiàn)降溫目的而應(yīng)用冰毛巾的早期實(shí)踐基礎(chǔ)上,一些廠商設(shè)計(jì)了用于運(yùn)動(dòng)員運(yùn)動(dòng)前或運(yùn)動(dòng)中降溫的冰夾克[137,142,163,164]。與CWI或混合降溫法相比[158],使用降溫背心時(shí)的核心溫度降低更少,但是降溫服體現(xiàn)了降低皮膚溫度這一優(yōu)勢(shì),繼而減小心血管壓力,最終可降低熱蓄積[165]。降溫服的實(shí)用性在于可在不降低肌肉溫度的情況下降低皮膚溫度,且運(yùn)動(dòng)員可在熱身或恢復(fù)間歇時(shí)穿著。
5.3冷液的攝取
在運(yùn)動(dòng)前[166,167]而非運(yùn)動(dòng)中[168,169]攝取冷液,可能會(huì)促進(jìn)耐力性運(yùn)動(dòng)能力的發(fā)揮。實(shí)際上,有人指出運(yùn)動(dòng)中攝取冷液的一個(gè)負(fù)面作用是可能減少出汗從而減少皮膚表面的蒸發(fā)[170],其應(yīng)歸因于可能位于腹部的溫度感受器的激活[171]。
5.4冰漿飲料
根據(jù)熱力學(xué)焓理論,與升高水溫所需的能量(4 J/g/℃)相比,冰需要更多的熱能(334 J/g)才能引起從固態(tài)到液態(tài)(0℃時(shí))這樣一個(gè)相變。因此,在使運(yùn)動(dòng)員降溫方面,冰漿可能較冷水?dāng)z入更有效。但是,尚不清楚與運(yùn)動(dòng)中冷水?dāng)z入成比例降低的汗液分泌[170]是否在攝取冰漿時(shí)發(fā)生。有幾項(xiàng)近期研究報(bào)告支持冰漿飲料的攝入,因?yàn)闊o論運(yùn)動(dòng)前[140,172,173]抑或運(yùn)動(dòng)中[174]攝取冰漿飲料后(~1 L碎冰,≤4℃),耐力運(yùn)動(dòng)或間歇沖刺運(yùn)動(dòng)的運(yùn)動(dòng)能力均得到改善。但是在另一項(xiàng)研究中,在兩回合運(yùn)動(dòng)的恢復(fù)間歇攝取冰漿,并無明顯的效益[175]。因此,冰漿的攝取可作為外用降溫法的一個(gè)實(shí)用補(bǔ)充或替代方法[155],但其在真實(shí)戶外比賽中的應(yīng)用仍需更多的研究。
5.5混合方法的降溫策略
混合方法(即同時(shí)使用體內(nèi)和體外降溫策略)較相同方法的單獨(dú)使用有著更高的降溫能力,這就使得在運(yùn)動(dòng)能力上可獲得更多的益處[158]。實(shí)際上,混合法降溫應(yīng)用于熱帶環(huán)境中比賽的足球運(yùn)動(dòng)員[176]、熱環(huán)境中訓(xùn)練的網(wǎng)棒球運(yùn)動(dòng)員[177](譯者注:又稱長(zhǎng)曲棍球)及實(shí)驗(yàn)室模擬比賽環(huán)境中的自行車運(yùn)動(dòng)員[139]時(shí),已經(jīng)被證明是有益的。在運(yùn)動(dòng)場(chǎng)景中,混合法降溫可通過組合簡(jiǎn)便的方法來實(shí)現(xiàn),例如飲用冰漿、穿戴降溫背心及提供風(fēng)扇。
5.6連續(xù)運(yùn)動(dòng)回合間降溫以改善運(yùn)動(dòng)能力
有證據(jù)支持在高溫環(huán)境中劇烈運(yùn)動(dòng)的組間恢復(fù)期(如15 min)可使用CWI(5~12min,水溫14℃)來改善后續(xù)的運(yùn)動(dòng)能力發(fā)揮[178,179]。該做法的益處可能與血流從皮膚到中心循環(huán)的重新分布[180]及心理(即安慰劑)效應(yīng)相關(guān)[181]。就體內(nèi)降溫而言,恢復(fù)期冷水[182]或冰漿[175]的攝入可能會(huì)減輕次回合運(yùn)動(dòng)的熱應(yīng)激壓力,但并不一定顯著提高運(yùn)動(dòng)能力[175]。這些研究結(jié)合到一起提示在不可代償?shù)膶?shí)驗(yàn)室熱應(yīng)激環(huán)境中,降溫可能會(huì)幫助劇烈運(yùn)動(dòng)后的恢復(fù),而且在某些情況下,還可能提高后續(xù)劇烈運(yùn)動(dòng)回合中的運(yùn)動(dòng)能力發(fā)揮。積極降溫與現(xiàn)場(chǎng)熱環(huán)境或更涼爽環(huán)境中簡(jiǎn)單休息的效果比較還有待比賽條件下(例如團(tuán)體項(xiàng)目中的中場(chǎng)休息)的驗(yàn)證。
5.7降溫策略主要建議總結(jié)
—降溫方法包括體外(例如冰服、毛巾、水浸泡或風(fēng)扇的應(yīng)用)和體內(nèi)(例如冷液或冰漿的攝入)降溫法。
—預(yù)冷降溫可能有益于熱環(huán)境中持久運(yùn)動(dòng)(例如中長(zhǎng)距離跑、自行車、網(wǎng)球和團(tuán)體項(xiàng)目)的體育活動(dòng)。體內(nèi)降溫法(即冰漿)可在運(yùn)動(dòng)中使用,而網(wǎng)球和團(tuán)體項(xiàng)目運(yùn)動(dòng)員也可在暫停休息間歇采用混合降溫法。
—對(duì)于相似環(huán)境中進(jìn)行的爆發(fā)力或較短時(shí)項(xiàng)目(例如沖刺、跳躍、投擲)來說,降溫策略可能是不可行的。
—使用風(fēng)扇和商用降溫冰背心可能是濕熱環(huán)境中的一個(gè)實(shí)用方法,它們可提供有效的降溫而不損害肌肉溫度。無論如何,降溫方法應(yīng)該在訓(xùn)練中進(jìn)行測(cè)試和個(gè)性化,以將對(duì)運(yùn)動(dòng)員的干擾減至最小程度。
賽事組織者調(diào)整或取消一項(xiàng)賽事所遵循的一系列最常見建議建立在濕球溫度(Wet bulb global temperature,WBGT)指數(shù)基礎(chǔ)上,該指數(shù)由美國(guó)軍隊(duì)均憑經(jīng)驗(yàn)發(fā)展而來并被美國(guó)運(yùn)動(dòng)醫(yī)學(xué)學(xué)會(huì)在運(yùn)動(dòng)醫(yī)學(xué)中進(jìn)行推廣[183],而且被不同的運(yùn)動(dòng)協(xié)會(huì)所采納(表2)。但是,當(dāng)汗液蒸發(fā)受到限制時(shí)(即高濕度和/或較低的空氣流動(dòng)),WBGT可能低估了熱應(yīng)激的風(fēng)險(xiǎn)[184]。因此,有學(xué)者提出了修正性建議[185](表3)。此外,WBGT是一個(gè)氣候指數(shù)且不能說明代謝產(chǎn)熱或穿衣著裝,因此不能預(yù)測(cè)熱量的散失[19]。所以,下文中的建議為不同體育活動(dòng)提供了指南而非基于WBGT指數(shù)的固定邊界點(diǎn)。
表2 不同運(yùn)動(dòng)管理機(jī)構(gòu)基于WBGT的建議措施示例
表3 基于WBGT的運(yùn)動(dòng)性中暑風(fēng)險(xiǎn)的校正估計(jì)——將WBGT低估高濕度下的熱應(yīng)激考慮在內(nèi)
6.1取消賽事抑或采取對(duì)策?
關(guān)于預(yù)期環(huán)境中任何賽事的適當(dāng)安排,當(dāng)疊加的外源性和內(nèi)源性熱負(fù)荷不能被生理代償時(shí),為保護(hù)運(yùn)動(dòng)員健康,可能需要停止比賽。生理代償極限被超越的環(huán)境條件取決于幾個(gè)因素,例如代謝產(chǎn)熱(取決于工作負(fù)荷和效率/經(jīng)濟(jì)性),運(yùn)動(dòng)員身體形態(tài)(例如體表面積-體重比),習(xí)服狀態(tài)(例如出汗率)與著裝。因此,不同運(yùn)動(dòng)項(xiàng)目建立統(tǒng)一的邊界值(Cut-off values)是不科學(xué)的。環(huán)境指標(biāo)應(yīng)被賽事組織者視為采取預(yù)防性對(duì)策以抵消中暑潛在風(fēng)險(xiǎn)的建議。建議的對(duì)策包括考慮到降溫間歇和液體補(bǔ)充可能性(時(shí)間和地點(diǎn))而修改規(guī)則,此外還包括在休息期提供主動(dòng)降溫。還建議應(yīng)將應(yīng)對(duì)運(yùn)動(dòng)性中暑的醫(yī)療響應(yīng)方案和設(shè)施準(zhǔn)備就緒。
6.2建議的特異性
6.2.1運(yùn)動(dòng)項(xiàng)目間的差異
熱環(huán)境會(huì)損害耐力運(yùn)動(dòng)能力,如馬拉松[7],但可能改善短時(shí)運(yùn)動(dòng)項(xiàng)目能力,如跳躍和沖刺[1]。很多運(yùn)動(dòng)中,運(yùn)動(dòng)員會(huì)根據(jù)環(huán)境條件來調(diào)整他們的活動(dòng)。例如,與較涼爽的環(huán)境相比,當(dāng)在高溫環(huán)境中(WBGT~34℃)運(yùn)動(dòng)時(shí),足球運(yùn)動(dòng)員會(huì)減少比賽中的總跑動(dòng)距離或高強(qiáng)度跑動(dòng)距離,維持他們的沖刺活動(dòng)/能力[9,12,186],而網(wǎng)球運(yùn)動(dòng)員會(huì)減少每分的得分時(shí)間[8]及增加每分之間的間歇時(shí)間[10]。因此,賽事組織者和國(guó)際協(xié)會(huì)應(yīng)通過相應(yīng)地修改規(guī)則和判罰來承認(rèn)和支持這樣的行為性體溫調(diào)節(jié)策略。
6.2.2給定運(yùn)動(dòng)項(xiàng)目中個(gè)體間的差異
當(dāng)比較兩項(xiàng)在墨爾本舉辦的鐵人三項(xiàng)比賽時(shí),兩項(xiàng)比賽的環(huán)境條件相似(即每項(xiàng)比賽中WBGT均從22℃上升到27℃),比賽間隔2個(gè)月,Gosling等[187]在第一項(xiàng)比賽中觀察到15例運(yùn)動(dòng)性中暑(包括3例熱射病(Heat stroke),其在夏初不合時(shí)令的炎熱天氣中舉行,但在第二項(xiàng)比賽中未見任何病例。該研究表明中暑的風(fēng)險(xiǎn)在那些可能未經(jīng)季節(jié)性熱習(xí)服的運(yùn)動(dòng)員中增加[187],且支持了許多關(guān)于夏初或炎熱天氣時(shí)中暑風(fēng)險(xiǎn)增加的早期研究[188]。盡管如此,運(yùn)動(dòng)性熱射病也可能發(fā)生在良好熱習(xí)服及之前已進(jìn)行過幾次相似活動(dòng)的個(gè)體中,因?yàn)樗麄兛赡茉谥邦净剂瞬《靖腥净蝾愃频募膊。?9]。在極少數(shù)結(jié)合WBGT和運(yùn)動(dòng)員疾病的流行病學(xué)研究中,Bahr等[22]在3年時(shí)間中調(diào)查了48場(chǎng)沙灘排球比賽(包括世界巡回賽和錦標(biāo)賽)。他們僅報(bào)告了1例與高溫相關(guān)的醫(yī)療退賽,其與一名因3天急性腸胃炎導(dǎo)致體液平衡受損的運(yùn)動(dòng)員相關(guān)[22]。而且,雖然健康的跑者也能完成溫濕環(huán)境中的半程馬拉松而不發(fā)生中暑[189],涼爽環(huán)境中的馬拉松賽時(shí),運(yùn)動(dòng)性熱射病已被證實(shí)可發(fā)生在正從病毒性感染中恢復(fù)的跑者上[190]。
事實(shí)上,先前的病毒感染正成為熱損傷/熱射病的潛在重要風(fēng)險(xiǎn)因素[19,191]。因此,賽事組織者應(yīng)該對(duì)可能處于較大風(fēng)險(xiǎn)的所有人群給予特別的醫(yī)療關(guān)注,包括正在生病或正從近期感染中恢復(fù)的參賽者、腹瀉者、近期免疫接種者、由于身體狀況(如殘奧會(huì)運(yùn)動(dòng)員)而散熱能力受限者或因規(guī)則限制了散熱能力(例如保護(hù)性的服裝/裝備)的運(yùn)動(dòng)項(xiàng)目參與者。未經(jīng)環(huán)境習(xí)服的參賽者也存在風(fēng)險(xiǎn)。盡管在大型賽事中篩查每個(gè)運(yùn)動(dòng)員是不切實(shí)際的,但是賽事組織者應(yīng)當(dāng)提供相關(guān)信息以告知運(yùn)動(dòng)員在不同的機(jī)體受損狀態(tài)下參賽時(shí)的相關(guān)風(fēng)險(xiǎn)及建議對(duì)策,這些信息可包含在注冊(cè)時(shí)發(fā)送的用品中。
6.3給賽事組織者的主要建議總結(jié)
—WBGT是一個(gè)環(huán)境熱應(yīng)激指數(shù),并不代表人體的熱應(yīng)激壓力。因此,跨越不同運(yùn)動(dòng)項(xiàng)目為不同運(yùn)動(dòng)員建立絕對(duì)的參賽分界值是非常困難的,當(dāng)制訂極限高溫環(huán)境策略時(shí),我們更愿意推薦采取預(yù)防性對(duì)策或評(píng)價(jià)運(yùn)動(dòng)的專項(xiàng)需求。
—對(duì)策包括根據(jù)氣候模式安排賽事的開始時(shí)間,修改規(guī)則和判罰以允許額外的暫停休息或更長(zhǎng)的恢復(fù)期,制定醫(yī)療響應(yīng)方案與開發(fā)降溫設(shè)施。
—賽事組織者應(yīng)特別關(guān)注所有的“風(fēng)險(xiǎn)”人群??紤]到未經(jīng)氣候習(xí)服的參賽者(主要在大眾參與的賽事中)面臨中暑的高風(fēng)險(xiǎn),賽事組織者應(yīng)適當(dāng)告知參賽者比賽相關(guān)的風(fēng)險(xiǎn),或考慮在意外或反常炎熱天氣條件下取消賽事。
我們當(dāng)前有關(guān)熱應(yīng)激的知識(shí)主要來源于軍事和職業(yè)研究領(lǐng)域,而運(yùn)動(dòng)科學(xué)方面的知識(shí)補(bǔ)充則是源于近期研究資料?;诒疚?,運(yùn)動(dòng)員應(yīng)至少訓(xùn)練1周,理想情況下2周,來進(jìn)行環(huán)境的習(xí)服,并使用與目標(biāo)賽事類似熱應(yīng)激程度的環(huán)境條件。運(yùn)動(dòng)員還應(yīng)注意,以在正常水合狀態(tài)下從事運(yùn)動(dòng),并通過運(yùn)動(dòng)中的適當(dāng)補(bǔ)水使身體水分的缺失(通過體重丟失的監(jiān)控)最小化。運(yùn)動(dòng)員還可采取專門的對(duì)策(例如降溫方法)來降低比賽和訓(xùn)練中的熱蓄積和生理應(yīng)激壓力,尤其是當(dāng)環(huán)境條件不可代償時(shí)。賽事組織者和運(yùn)動(dòng)主管機(jī)構(gòu)可通過允許高溫環(huán)境比賽中的額外(或更長(zhǎng))恢復(fù)期以促進(jìn)補(bǔ)水和提供降溫時(shí)機(jī)來支持運(yùn)動(dòng)員。
[1]Racinais S,Oksa J.Temperature and neuromuscular function. Scand J Med Sci Sports.2010,20(Suppl 3):1–18.
[2]Nybo L,Rasmussen P,Sawka MN.Performance in the heat—physiological factors of importance for hyperthermia-induced fatigue.Compr Physiol.2014,4:657–89.
[3]Periard J,Racinais S.Editorial:training and competing in the heat.Scand J Med Sci Sports.2015,25(Suppl 1):2–4.
[4]Rowell LB.Human cardiovascular adjustments to exercise and thermal stress.Physiol Rev.1974,54:75–159.
[5]Galloway SD,Maughan RJ.Effects of ambient temperature on the capacity to perform prolonged cycle exercise in man.Med Sci Sports Exerc.1997,29:1240–9.
[6]Périard JD,Cramer MN,Chapman PG,et al.Cardiovascular strain impairs prolonged self-paced exercise in the heat.Exp Physiol.2011,96:134–44.
[7]Ely MR,Cheuvront SN,Roberts WO,et al.Impact of weather on marathon-running performance.Med Sci Sports Exerc. 2007,39:487–93.
[8]Morante SM,Brotherhood JR.Autonomic and behavioural thermoregulation in tennis.Br J Sports Med.2008,42:679–85.(discussion 685).
[9]Mohr M,Nybo L,Grantham J,et al.Physiological responses and physical performance during football in the heat.PLoS One.2012,7:e39202.
[10]Périard JD,Racinais S,Knez WL,et al.Thermal,physiological and perceptual strain mediate alterations in match-play tennis under heat stress.Br J Sports Med.2014,48(Suppl 1):i32–8.
[11]Racinais S,Périard JD,Karlsen A,et al.Effect of heat and heat acclimatization on cycling time trial performance and pacing.Med Sci Sports Exerc.2015,47:601-6.
[12]NassisGP,BritoJ,DvorakJ,etal.Theassociationof environmental heat stress with performance:analysis of the 2014 FIFA World Cup Brazil.Br J Sports Med.2015,49:609–13.
[13]Adolph EF.Physiology of man in the desert.New York:Interscience,1947.
[14]Strydom NB,Holdsworth LD.The effects of different levels of water deficit on physiological responses during heat stress.Int Z Angew Physiol.1968,26:95–102.
[15]SawkaMN,YoungAJ,F(xiàn)rancesconiRP,etal. Thermoregulatory and blood responses during exercise at graded hypohydration levels.J Appl Physiol.1985,59:1394–401.
[16]Montain SJ,Coyle EF.Influence of graded dehydration on hyperthermia and cardiovascular drift during exercise.J Appl Physiol.1992,73:1340–50.
[17]González-AlonsoJ,CrandallCG,JohnsonJM.The cardiovascular challenge of exercising in the heat.J Physiol. 2008,586:45–53.
[18]Trangmar SJ,Chiesa ST,Stock CG,et al.Dehydration affects cerebral blood flow but not its metabolic rate for oxygen during maximal exercise in trained humans.J Physiol.2014,592:3143–60.
[19]Sawka MN,Leon LR,Montain SJ,et al.Integrated physiological mechanisms of exercise performance,adaptation,and maladaptation to heat stress.Compr Physiol.2011,1:1883-928.
[20]Bergeron MF,Bahr R,B?rtsch P,et al.International Olympic Committeeconsensusstatementonthermoregulatoryand altitude challenges for high-level athletes.Br J Sports Med. 2012,46:770-9.
[21]Grantham J,Cheung SS,Connes P,et al.Current knowledge on playing football in hot environments.Scand J Med Sci Sports.2010,20(Suppl 3):161–7.
[22]Bahr R,Reeser JC.New guidelines are needed to manage heat stress in elite sports—the Fédération Internationale de Volleyball(FIVB)Heat Stress Monitoring Programme.Br J Sports Med.2012,46:805–9.
[23]Mountjoy M,Alonso J-M,Bergeron MF,et al.Hyperthermicrelated challenges in aquatics,athletics,football,tennis and triathlon.Br J Sports Med.2012,46:800–4.
[24]ArmstrongLE,PandolfKB.Physicaltraining,cardiorespiratory physical fitness and exercise-heat tolerance. In:Pandolf KB,Sawka MN,Gonzalez RR,editors.Physiology andenvironmentalmedicineatterrestrialextremes. Indianapolis:PhysiologyandEnvironmentalMedicineat Terrestrial Extremes,1988:199-226.
[25]Gisolfi C,Robinson S.Relations between physical training,acclimatization,and heat tolerance.J Appl Physiol.1969,26:530-4.
[26]Nadel ER,Pandolf KB,Roberts MF,et al.Mechanisms of thermal acclimation to exercise and heat.J Appl Physiol. 1974,37:515-20.
[27]Roberts MF,Wenger CB,Stolwijk JA,et al.Skin blood flow and sweating changes following exercise training and heat acclimation.J Appl Physiol.1977,43:133-7.
[28]Nielsen B,Hales JR,Strange S,et al.Human circulatory and thermoregulatoryadaptationswithheatacclimationand exercise in a hot,dry environment.J Physiol.1993,460:467-85.
[29]Lorenzo S,Halliwill JR,Sawka MN,et al.Heat acclimation improves exercise performance.J Appl Physiol.2010,109:1140-7.
[30]SawkaMN,WengerCB,PandolfKB.Thermoregulatory responses to acute exercise‐heat stress and heat acclimation. In:Fregly MJ,Blatteis CM,editors.Handbook of physiology. Section?4,environmentalphysiology.NewYork:Oxford University Press,1996:157–85.
[31]PeriardJ,RacinaisS,SawkaMN.Adaptationsand mechanismsofhumanheatacclimation:applicationsfor competitive athletes and sports.Scand J Med Sci Sports. 2015,25(Suppl 1):20–38.
[32]RobinsonS,TurrellES,BeldingHS,etal.Rapid acclimatization to work in hot climates.Am J Physiol.1943,140:168–76.
[33]Ladell WS.Assessment of group acclimatization to heat and humidity.J Physiol.1951,115:296–312.
[34]Flouris AD,Poirier MP,Bravi A,et al.Changes in heart rate variability during the induction and decay of heat acclimation. Eur J Appl Physiol.2014,114:2119–28.
[35]Pandolf KB,Burse RL,Goldman RF.Role of physical fitness in heat acclimatisation,decay and reinduction.Ergonomics. 1977,20:399–408.
[36]Sunderland C,Morris JG,Nevill ME.A heat acclimation protocol for team sports.Br J Sports Med.2008,42:327–33.
[37]Garrett AT,Rehrer NJ,Patterson MJ.Induction and decay of short-term heat acclimation in moderately and highly trained athletes.Sports Med.2011,41:757–71.
[38]Chalmers S,Esterman A,Eston R,et al.Short-term heat acclimationtrainingimprovesphysicalperformance:a systematic review,and exploration of physiological adaptations and application for team sports.Sports Med.2014,44:971–88.
[39]Karlsen A,Nybo L,Norgaard SJ,et al.Time course of natural heat acclimatization in well-trained cyclists during a 2-week training camp in the heat.Scand J Med Sci Sports.2015,25(Suppl 1):240–9.
[40]Lind AR,Bass DE.Optimal exposure time for development of acclimatization to heat.Fed Proc.1963,22:704–8.
[41]Houmard JA,Costill DL,Davis JA,et al.The influence of exercise intensity on heat acclimation in trained subjects. Med Sci Sports Exerc.1990,22:615–20.
[42]Taylor NAS.Human heat adaptation.Compr Physiol.2014,4:325–65.
[43]PattersonMJ,StocksJM,TaylorNAS.Sustainedand generalizedextracellularfluidexpansionfollowingheat acclimation.J Physiol.2004,559:327–34.
[44]Garrett AT,Goosens NG,Rehrer NJ,et al.Induction and decay of short-term heat acclimation.Eur J Appl Physiol. 2009,107:659–70.
[45]Racinais S,Mohr M,Buchheit M,et al.Individual responses to short-term heat acclimatisation as predictors of football performance in a hot,dry environment.Br J Sports Med. 2012,46:810–5.
[46]Racinais S,Buchheit M,Bilsborough J,et al.Physiological and performance responses to a training camp in the heat in professional Australian football players.Int J Sports Physiol Perform.2014,9:598–603.
[47]BeanWB,EichnaLA.Performanceinrelationto environmental temperature.Reactions of normal young men to simulated desert environments.Fed Proc.1943,2:144–58.
[48]Fox RH,Goldsmith R,Hampton IF,et al.Heat acclimatization by controlled hyperthermia in hot-dry and hot-wet climates.J Appl Physiol.1967,22:39–46.
[49]Eichna LW,Bean WB,William F.Performance in relation to environmental temperature.Reactions of normal young men tohot,humid(simulatedjungle)environment.BullJohns Hopkins Hosp.1945,76:25058.
[50]Candas V,Libert JP,Vogt JJ.Influence of air velocity and heat acclimation on human skin wettedness and sweating efficiency.J Appl Physiol.1979,47:1194–200.
[51]Sawka MN,Cheuvront SN,Kolka MA.Human adaptation to heatstress.In:NoseH,MackGW,ImaizumiK,editors. Exercise,nutrition and environmental stress.Traverse City:Cooper Publishing Group,2003:129–53.
[52]Hellon RF,Jones RM,MacPherson RK,et al.Natural and artificial acclimatization to hot environments.J Physiol.1956,132:559–76.
[53]Edholm OG.The physiology of adaptation.Eugen Rev.1966,58:136–42.
[54]Armstrong L,Maresh C.The induction and decay of heat acclimatisation in trained athletes.Sports Med.1991,12:302.
[55]Dresoti AO.The results of some investigations into the medical aspects of deep mining on the Witwatersrand.J Chem Metal Min Soc S Afr.1935,6:102–29.
[56]Lind AR.Physiologic responses to heat.In:Licht S,editor. Medical climatology.Baltimore:Medical Climatology,1964:164–95.
[57]Weller AS,Linnane DM,Jonkman AG,et al.Quantification of the decay and re-induction of heat acclimation in dry-heat following 12 and 26 days without exposure to heat stress.Eur J Appl Physiol.2007,102:57–66.
[58]Daanen HAM,Jonkman AG,Layden JD,et al.Optimising the acquisition and retention of heat acclimation.Int J Sports Med.2011,32:822–8.
[59]Eichna LW,Park CR,Nelson N,et al.Thermal regulation duringacclimatizationinahot,dry(deserttype)environment.Am J Physiol.1950,163:585–97.
[60]MacDonald DKC,Wyndham CH.Heat transfer in man.J Appl Physiol.1950,3:342–64.
[61]Lee D.A basis for the study of man's reaction to tropical climates.Univ Qld Pap Dept Physiol.1940,1:86.
[62]BuchheitM,VossSC,NyboL,etal.Physiologicaland performance adaptations to an in-season soccer camp in the heat:associations with heart rate and heart rate variability. Scand J Med Sci Sports.2011,21:e477–85.
[63]Buchheit M,Racinais S,Bilsborough J,et al.Adding heat to the live-high train-low altitude model:a practical insight from professional football.Br J Sports Med.2013,47(Suppl 1):i59–69.
[64]Dill DB,Hall FG,Edwards HT.Changes in composition of sweat during acclimatization to heat.Am J Physiol.1938,123:412–9.
[65]Glaser EM.Acclimatization to heat and cold.J Physiol.1950,110:330–7.
[66]Sawka MN,Coyle EF.Influence of body water and blood volume on thermoregulation and exercise performance in the heat.Exerc Sport Sci Rev.1999,27:167–218.
[67]Watt MJ,Garnham AP,F(xiàn)ebbraio MA,et al.Effect of acute plasma volume expansion on thermoregulation and exercise performance in the heat.Med Sci Sports Exerc.2000,32:958–62.
[68]Armstrong LE,Hubbard RW,DeLuca JP,et al.Evaluation of a temperate environment test to predict heat tolerance.Eur J Appl Physiol Occup Physiol.1987,56:384–9.
[69]Hue O,Antoine-Jonville S,Sara F.The effect of 8 days of training in tropical environment on performance in neutral climate in swimmers.Int J Sports Med.2007,28:48–52.
[70]Scoon GSM,Hopkins WG,Mayhew S,et al.Effect of postexercise sauna bathing on the endurance performance of competitive male runners.J Sci Med Sport.2007,10:259–62.
[71]Karlsen A,Racinais S,Jensen MV,et al.Heat acclimatization does not improve?VO2max?or cycling performance in a cool climate in trained cyclists.Scand J Med Sci Sports.2015,25(Suppl 1):269–76.
[72]Nadel ER,F(xiàn)ortney SM,Wenger CB.Effect of hydration state of circulatory and thermal regulations.J Appl Physiol.1980,49:715–21.
[73]FortneySM,WengerCB,BoveJR,etal.Effectof hyperosmolality on control of blood flow and sweating.J Appl Physiol.1984,57:1688–95.
[74]MontainSJ,LatzkaWA,SawkaMN.Controlof thermoregulatory sweating is altered by hydration level and exercise intensity.J Appl Physiol.1995,79:1434–9.
[75]González-Alonso J,Mora-Rodríguez R,Below PR,et al. Dehydration reduces cardiac output and increases systemic and cutaneous vascular resistance during exercise.J Appl Physiol.1995,79:1487–96.
[76]González-Alonso J,Calbet JA,Nielsen B.Muscle blood flow is reduced with dehydration during prolonged exercise in humans.J Physiol.1998,513(Pt 3):895–905.
[77]St?hr EJ,González-Alonso J,Pearson J,et al.Dehydration reduces left ventricular filling at rest and during exercise independent of twist mechanics.J Appl Physiol.2011,111:891–7.
[78]Sawka MN,Toner MM,F(xiàn)rancesconi RP,et al.Hypohydration andexercise:effectsofheatacclimation,gender,and environment.J Appl Physiol.1983,55:1147–53.
[79]Sawka MN.Physiological consequences of hypohydration:exercise performance and thermoregulation.Med Sci Sports Exerc.1992,24:657–70.
[80]González-Alonso J,Mora-Rodríguez R,Coyle EF.Stroke volumeduringexercise:interactionofenvironmentand hydration.Am J Physiol Heart Circ Physiol.2000,278:H321–30.
[81]CheuvrontSN,KenefickRW.Dehydration:physiology,assessment,and performance effects.Compr Physiol.2014,4:257–85.
[82]Goulet EDB.Effect of exercise-induced dehydration on timetrial exercise performance:a meta-analysis.Br J Sports Med. 2011,45:1149–56.
[83]Goulet EDB.Effect of exercise-induced dehydration on endurance performance:evaluating the impact of exercise protocols on outcomes using a meta-analytic procedure.Br J Sports Med.2013,47:679–86.
[84]Cotter JD,Thornton SN,Lee JK,et al.Are we being drowned in hydration advice?Thirsty for more?Extrem Physiol Med.2014,3:18
[85]Below PR,Mora-Rodríguez R,González-Alonso J,et al.Fluid andcarbohydrateingestionindependentlyimprove performance during 1 h of intense exercise.Med Sci Sports Exerc.1995,27:200–10.
[86]Cheung SS,McLellan TM.Heat acclimation,aerobic fitness,and hydration effects on tolerance during uncompensable heat stress.J Appl Physiol.1998,84:1731–9.
[87]Ebert TR,Martin DT,Bullock N,et al.Influence of hydration status on thermoregulation and cycling hill climbing.Med Sci Sports Exerc.2007,39:323–9.
[88]KenefickRW,CheuvrontSN,PalomboLJ,etal.Skin temperature modifies the impact of hypohydration on aerobic performance.J Appl Physiol.2010,109:79–86.
[89]Merry TL,Ainslie PN,Cotter JD.Effects of aerobic fitness on hypohydration-induced physiologicalstrainandexercise impairment.Acta Physiol(Oxf).2010,198:179–90.
[90]SawkaMN,CheuvrontSN,KenefickRW.Highskin temperature and hypohydration impair aerobic performance. Exp Physiol.2012,97:327–32.
[91]WallBA,WatsonG,PeifferJJ,etal.Currenthydration guidelines are erroneous:dehydration does not impair exercise performance in the heat.Br J Sports Med.2013.doi:10.?1136/?bjsports-2013-092417.
[92]Cohen D.The truth about sports drinks.BMJ.2012,345:e4737.
[93]Adolph EF,Dill DB.Observations on water metabolism in the desert.Am J Physiol.1938,123:369–78.
[94]Greenleaf JE,Sargent F.Voluntary dehydration in man.J Appl Physiol.1965,20:719–24.
[95]Greenleaf JE,Brock PJ,Keil LC,et al.Drinking and water balance during exercise and heat acclimation.J Appl Physiol. 1983,54:414–9.
[96]Armstrong LE,Costill DL,F(xiàn)ink WJ.Influence of diureticinduced dehydration on competitive running performance. Med Sci Sports Exerc.1985,17:456–61.
[97]GreenleafJE.Problem:thirst,drinkingbehavior,and involuntary dehydration.Med Sci Sports Exerc.1992,24:645–56.
[98]Cheuvront SN,Haymes EM.Ad libitum fluid intakes and thermoregulatory responses of female distance runners in three environments.J Sports Sci.2001,19:845–54.
[99]Zouhal H,Groussard C,Minter G,et al.Inverse relationship between percentage body weight change and finishing time in 643 forty-two-kilometre marathon runners.Br J Sports Med. 2011,45:1101–5.
[100]Noakes TD,Goodwin N,Rayner BL,et al.Water intoxication:a possible complication during endurance exercise.Med Sci Sports Exerc.1985,17:370–5.
[101]Noakes TD.Overconsumption of fluids by athletes.BMJ. 2003,327:113–4.
[102]Almond CSD,Shin AY,F(xiàn)ortescue EB,et al.Hyponatremia among runners in the Boston Marathon.N Engl J Med.2005,352:1550–6.
[103]Institute of Medicine(US).Dietary reference intakes for water,potassium,sodium,chloride,and sulfate.Washington,DC:The National Academies Press,2004:73–423.
[104]Cheuvront SN,Carter R,Montain SJ,et al.Daily body mass variability and stability in active men undergoing exerciseheat stress.Int J Sport Nutr Exerc Metab.2004,14:532–40.
[105]CheuvrontSN,ElyBR,KenefickRW,etal.Biological variation and diagnostic accuracy of dehydration assessment markers.Am J Clin Nutr.2010,92:565–73.
[106]CheuvrontSN,KenefickRW,CharkoudianN,etal. Physiologic basis for understanding quantitative dehydration assessment.Am J Clin Nutr.2013,97:455–62.
[107]Cheuvront SN,Montain SJ,Goodman DA,et al.Evaluation of the limits to accurate sweat loss prediction during prolonged exercise.Eur J Appl Physiol.2007,101:215–24.
[108]AdamsWC,F(xiàn)oxRH,F(xiàn)ryAJ.Thermoregulationduring marathon running in cool,moderate,and hot environments.J Appl Physiol.1975,38:1030–7.
[109]BergeronMF,ArmstrongLE,MareshCM.Fluidand electrolyte losses during tennis in the heat.Clin Sports Med. 1995,14:23–32.
[110]BergeronMF,MareshCM,ArmstrongLE,etal.Fluidelectrolyte balance associated with tennis match play in a hot environment.Int J Sport Nutr.1995,5:180–93.
[111]Shirreffs SM,Sawka MN,Stone M.Water and electrolyte needs for football training and match-play.J Sports Sci. 2006,24:699–707.
[112]Shapiro Y,Pandolf KB,Goldman RF.Predicting sweat loss response to exercise,environment and clothing.Eur J Appl Physiol Occup Physiol.1982,48:83–96.
[113]Barr SI,Costill DL.Water:can the endurance athlete get too much of a good thing?J Am Diet Assoc.1989,89:1629–35.
[114]Montain SJ,Cheuvront SN,Sawka MN.Exercise associated hyponatraemia:quantitativeanalysistounderstandthe aetiology.Br J Sports Med.2006,40:98–105.?(discussion 98–105).
[115]Gonzalez RR,Cheuvront SN,Montain SJ,et al.Expanded prediction equations of human sweat loss and water needs.J Appl Physiol.2009,107:379–88.
[116]GonzalezRR,CheuvrontSN,ElyBR,etal.Sweatrate prediction equations for outdoor exercise with transient solar radiation.J Appl Physiol.2012,112:1300–10.
[117]Jay O,Webb P.Improving the prediction of sweat losses during exercise.J Appl Physiol.2009,107:375–6.
[118]Costill DL.Sweating:its composition and effects on body fluids.Ann N Y Acad Sci.1977,301:160–74.
[119]Verde T,Shephard RJ,Corey P,et al.Sweat composition in exercise and in heat.J Appl Physiol.1982,53:1540–5.
[120]Bergeron MF.Muscle cramps during exercise—is it fatigue or electrolyte deficit?Curr Sports Med Rep.2008,7:S50–5.
[121]Casa DJ.Exercise in the heat.II.Critical concepts in rehydration,exertional heat illnesses,and maximizing athletic performance.J Athl Train.1999,34:253–62.
[122]von Duvillard SP,Braun WA,Markofski M,et al.Fluids and hydration in prolonged endurance performance.Nutrition. 2004,20:651–6.
[123]American College of Sports Medicine,Sawka MN,Burke LM,et al.American College of Sports Medicine position stand. Exercise and fluid replacement.Med Sci Sports Exerc.2007,39:377–90.
[124]Bergeron MF.Heat cramps:fluid and electrolyte challenges during tennis in the heat.J Sci Med Sport.2003,6:19–27.
[125]Burke LM,Hawley JA,Wong SHS,et al.Carbohydrates for training and competition.J Sports Sci.2011,29(Suppl 1):S17–27.
[126]Shirreffs SM,Maughan RJ.Volume repletion after exerciseinduced volume depletion in humans:replacement of water and sodium losses.Am J Physiol.1998,274:F868–75.
[127]Febbraio MA,Snow RJ,Stathis CG,et al.Effect of heat stress on muscle energy metabolism during exercise.J Appl Physiol. 1994,77:2827–31.
[128]González-Alonso J,Calbet JA,Nielsen B.Metabolic and thermodynamic responses to dehydration-induced reductions in muscle blood flow in exercising humans.J Physiol.1999,520(Pt 2):577–89.
[129]Burke LM.Nutritional needs for exercise in the heat.Comp Biochem Physiol A Mol Integr Physiol.2001,128:735–48.
[130]Ivy JL,Katz AL,Cutler CL,et al.Muscle glycogen synthesis after exercise:effect of time of carbohydrate ingestion.J Appl Physiol.1988,64:1480–5.
[131]James L.Milk protein and the restoration of fluid balance after exercise.Med Sport Sci.2012,59:120–6.
[132]Beelen M,Burke LM,Gibala MJ,et al.Nutritional strategies to promote postexercise recovery.Int J Sport Nutr Exerc Metab.2010,20:515–32.
[133]Pritchett K,Pritchett R.Chocolate milk:a post-exercise recovery beverage for endurance sports.Med Sport Sci.2012,59:127–34.
[134]Booth J,Marino F,Ward JJ.Improved running performance in hot humid conditions following whole body precooling.Med Sci Sports Exerc.1997,29:943–9.
[135]González-Alonso J,Teller C,Andersen SL,et al.Influence of body temperature on the development of fatigue during prolonged exercise in the heat.J Appl Physiol.1999,86:1032–9.
[136]Quod MJ,Martin DT,Laursen PB,et al.Practical precooling:effect on cycling time trial performance in warm conditions.J Sports Sci.2008,26:1477–87.
[137]Duffield R,Green R,Castle P,et al.Precooling can prevent the reduction of self-paced exercise intensity in the heat. Med Sci Sports Exerc.2010,42:577–84.
[138]Ihsan M,Landers G,Brearley M,et al.Beneficial effects of ice ingestion as a precooling strategy on 40-km cycling timetrial performance.Int J Sports Physiol Perform.2010,5:140–51.
[139]RossMLR,GarvicanLA,JeacockeNA,etal.Novel precooling strategy enhances time trial cycling in the heat. Med Sci Sports Exerc.2011,43:123–33.
[140]Siegel R,Maté J,Watson G,et al.Pre-cooling with ice slurry ingestion leads to similar run times to exhaustion in the heat as cold water immersion.J Sports Sci.2012,30:155–65.
[141]Marsh D,Sleivert G.Effect of precooling on high intensity cycling performance.Br J Sports Med.1999,33:393–7.
[142]Duffield R,Marino FE.Effects of pre-cooling procedures on intermittent-sprint exercise performance in warm conditions. Eur J Appl Physiol.2007,100:727–35.
[143]Castle P,Mackenzie RW,Maxwell N,et al.Heat acclimation improves intermittent sprinting in the heat but additional precooling offers no further ergogenic effect.J Sports Sci.2011,29:1125–34.
[144]Minett GM,Duffield R,Marino FE,et al.Volume-dependent response of precooling for intermittent-sprint exercise in the heat.Med Sci Sports Exerc.2011,43:1760–9.
[145]BradeC,DawsonB,WallmanK.Effectsofdifferent precooling techniques on repeat sprint ability in team sport athletes.Eur J Sports Sci.2014,14(Suppl 1):S84–91.
[146]Duffield R,Dawson B,Bishop D,et al.Effect of wearing an ice cooling jacket on repeat sprint performance in warm/ humid conditions.Br J Sports Med.2003,37:164–9.
[147]Cheung S,Robinson A.The influence of upper-body precooling on repeated sprint performance in moderate ambient temperatures.J Sports Sci.2004,22:605–12.
[148]Brade C,Dawson B,Wallman K.Effect of precooling and acclimation on repeat-sprint performance in heat.J Sports Sci.2013,31:779–86.
[149]Sleivert GG,Cotter JD,Roberts WS,et al.The influence of whole-body vs.torso pre-cooling on physiological strain and performance of high-intensity exercise in the heat.Comp Biochem Physiol A Mol Integr Physiol.2001,128:657–66.
[150]Castle PC,Macdonald AL,Philp A,et al.Precooling leg muscle improves intermittent sprint exercise performance in hot,humid conditions.J Appl Physiol.2006,100:1377–84.
[151]Marino FE.Methods,advantages,and limitationsofbody cooling for exercise performance.Br J Sports Med.2002,36:89–94.
[152]Quod MJ,Martin DT,Laursen PB.Cooling athletes before competitionintheheat:comparisonoftechniquesand practical considerations.Sports Med.2006,36:671–82.
[153]Duffield R.Cooling interventions for the protection and recovery of exercise performance from exercise-induced heat stress.Med Sport Sci.2008,53:89–103.
[154]Jones PR,Barton C,Morrissey D,et al.Pre-cooling for endurance exercise performance in the heat:a systematic review.BMC Med.2012,10:166.
[155]SiegelR,LaursenPB.Keepingyourcool:possible mechanisms for enhanced exercise performance in the heat with internal cooling methods.Sports Med.2012,42:89–98.
[156]Ross M,Abbiss C,Laursen P,et al.Precooling methods and their effects on athletic performance:a systematic review and practical applications.Sports Med.2013,43:207–25.
[157]Tyler CJ,Sunderland C,Cheung SS.The effect of cooling prior to and during exercise on exercise performance and capacity in the heat:a meta-analysis.Br J Sports Med.2015,49:7–13.
[158]BongersCCWG,ThijssenDHJ,VeltmeijerMTW,etal. Precooling and percooling(cooling during exercise)both improve performance in the heat:a meta-analytical review.Br J Sports Med.2015,49:377–84.
[159]Morrison SA,Cheung S,Cotter JD.Importance of airflow for physiologic and ergogenic effects of precooling.J Athl Train. 2014,49:632–9.
[160]LeederJ,GissaneC,vanSomerenK,etal.Coldwaterimmersion and recovery from strenuous exercise:a metaanalysis.Br J Sports Med.2012,46:233–40.
[161]DeGroot DW,Gallimore RP,Thompson SM,et al.Extremity cooling for heat stress mitigation in military and occupational settings.J Therm Biol.2013,38:305–10.
[162]VerseyNG,HalsonSL,DawsonBT.Waterimmersion recovery for athletes:effect on exercise performance and practical recommendations.Sports Med.2013,43:1101–30.
[163]Cotter JD,Sleivert GG,Roberts WS,et al.Effect of precooling,withandwithoutthighcooling,onstrainand endurance exercise performance in the heat.Comp Biochem Physiol A Mol Integr Physiol.2001,128:667–77.
[164]Arngr?msson SA,Petitt DS,Stueck MG,et al.Cooling vest worn during active warm-up improves 5-km run performance in the heat.J Appl Physiol.2004,96:1867–74.
[165]Cheuvront SN,Kolka MA,Cadarette BS,et al.Efficacy of intermittent,regional microclimate cooling.J Appl Physiol. 2003,94:1841–8.
[166]Lee JKW,Shirreffs SM,Maughan RJ.Cold drink ingestion improves exercise endurance capacity in the heat.Med Sci Sports Exerc.2008,40:1637–44.
[167]Byrne C,Owen C,Cosnefroy A,et al.Self-paced exercise performance in the heat after pre-exercise cold-fluid ingestion.J Athl Train.2011,46:592–9.
[168]Lee JKW,Shirreffs SM.The influence of drink temperature on thermoregulatory responses during prolonged exercise in a moderate environment.J Sports Sci.2007,25:975–85.
[169]Lee JKW,Maughan RJ,Shirreffs SM.The influence of serial feedingofdrinksatdifferenttemperatureson thermoregulatory responses during cycling.J Sports Sci. 2008,26:583–90.
[170]Bain AR,Lesperance NC,Jay O.Body heat storage during physical activity is lower with hot fluid ingestion under conditions that permit full evaporation.Acta Physiol(Oxf). 2012,206:98–108.
[171]MorrisNB,BainAR,CramerMN,etal.Evidencethat transient changes in sudomotor output with cold and warm fluid ingestion are independently modulated by abdominal,but not oral thermoreceptors.J Appl Physiol.2014,116:1088–95.
[172]Siegel R,Maté J,Brearley MB,et al.Ice slurry ingestion increases core temperature capacity and running time in the heat.Med Sci Sports Exerc.2010,42:717–25.
[173]Yeo ZW,F(xiàn)an PWP,Nio AQX,et al.Ice slurry on outdoor running performance in heat.Int J Sports Med.2012,33:859–66.
[174]Stevens CJ,Dascombe B,Boyko A,et al.Ice slurry ingestion duringcyclingimprovesOlympicdistancetriathlon performance in the heat.J Sports Sci.2013,31:1271–9.
[175]Stanley J,Leveritt M,Peake JM.Thermoregulatory responses to ice-slush beverage ingestion and exercise in the heat.Eur J Appl Physiol.2010,110:1163–73.
[176]Duffield R,Coutts A,McCall A,et al.Pre-cooling for football training and competition in hot and humid conditions.Eur J Sports Sci.2013,13:58–67.
[177]Duffield R,Steinbacher G,F(xiàn)airchild TJ.The use of mixedmethod,part-body pre-cooling procedures for team-sport athletes training in the heat.J Strength Cond Res.2009,23:2524–32.
[178]YearginSW,CasaDJ,McClungJM,etal.Bodycooling betweentwoboutsofexerciseintheheatenhances subsequent performance.J Strength Cond Res.2006,20:383–9.
[179]Peiffer JJ,Abbiss CR,Watson G,et al.Effect of a 5-min cold-water immersion recovery on exercise performance in the heat.Br J Sports Med.2010,44:461–5.
[180]Vaile J,O'Hagan C,Stefanovic B,et al.Effect of cold water immersion on repeated cycling performance and limb blood flow.Br J Sports Med.2011,45:825–9.
[181]Hornery DJ,Papalia S,Mujika I,et al.Physiological and performance benefits of halftime cooling.J Sci Med Sport. 2005,8:15–25.
[182]Lee JKW,Yeo ZW,Nio AQX,et al.Cold drink attenuates heat strain during work-rest cycles.Int J Sports Med.2013,34:1037–42.
[183]American College of Sports Medicine,Armstrong LE,Casa DJ,et al.American College of Sports Medicine position stand. Exertional heat illness during training and competition.Med Sci Sports Exerc.2007,39:556–72.
[184]Budd GM.Wet-bulb globe temperature(WBGT)-its history and its limitations.J Sci Med Sport.2008,11:20–32.
[185]Gonzalez RR.Biophysics of heat exchange and clothing:applications to sports physiology.Med Exerc Nutr Health. 1995,4:290–305.
[186]Aughey RJ,Goodman CA,Mckenna MJ.Greater chance of high core temperatures with modified pacing strategy during team sport in the heat.J Sci Med Sport.2014,17:113–8.
[187]Gosling CM,Gabbe BJ,McGivern J,et al.The incidence of heat casualties in sprint triathlon:the tale of two Melbourne race events.J Sci Med Sport.2008,11:52–7.
[188]Sartor F,Snacken R,Demuth C,et al.Temperature,ambient ozone levels,and mortality during summer 1994,in Belgium. Environ Res.1995,70:105–13.
[189]ByrneC,LeeJKW,ChewSAN,etal.Continuous thermoregulatory responses to mass-participation distance running in heat.Med Sci Sports Exerc.2006,38:803–10.
[190]Roberts WO.Exertional heat stroke during a cool weather marathon:a case study.Med Sci Sports Exerc.2006,38:1197–203.
[191]Sonna LA,Wenger CB,F(xiàn)linn S,et al.Exertional heat injury and gene expression changes:a DNA microarray analysis study.J Appl Physiol.2004,96:1943–53.
[192]Roberts WO.Determining a“do not start”temperature for a marathon on the basis of adverse outcomes.Med Sci Sports Exerc.2010,42:226–32.
Consensus Recommendations on Training and Competing in the Heat
Original Authors:Sébastien Racinais,Juan-Manuel Alonso,Aaron J.Coutts,Andreas D.Flouris,Olivier Girard,José González-Alonso,Christophe Hausswirth,Ollie Jay,Jason K.W.Lee,Nigel Mitchell,George P. Nassis,Lars Nybo,Babette M.Pluim,Bart Roelands,Michael N.Sawka,Jonathan Wingo,Julien D.Périard.
Sébastien Racinais,Email:sebastien.racinais@aspetar.com
國(guó)家自然科學(xué)基金(31371195);國(guó)家體育總局重點(diǎn)領(lǐng)域課題(委14-08);國(guó)家科技部公益性研究院所專項(xiàng)基金項(xiàng)目(基本14-03)
注:本譯文的發(fā)表已獲得原文作者的許可。該共識(shí)性建議原文于2015年5月或6月已免費(fèi)開源(Open Access)發(fā)表在《運(yùn)動(dòng)醫(yī)學(xué)》(Sports Medicine;http://link.springer.com/article/10.1007/s40279-015-0343-6)、《英國(guó)運(yùn)動(dòng)醫(yī)學(xué)雜志》(British Journal of Sports Medicine;http://bjsm.bmj.com/content/49/18/1164. long)、《斯堪的納維亞運(yùn)動(dòng)醫(yī)學(xué)與科學(xué)雜志》(Scandinavian Journal of Medicine and Science in Sports;http://onlinelibrary.wiley.com/doi/10.1111/sms.12467/full)。