ترجمه مقاله نقش ضروری ارتباطات 6G با چشم انداز صنعت 4.0
- مبلغ: ۸۶,۰۰۰ تومان
ترجمه مقاله پایداری توسعه شهری، تعدیل ساختار صنعتی و کارایی کاربری زمین
- مبلغ: ۹۱,۰۰۰ تومان
YOUNG, ANDREW, J., STEPHEN R. MUZA, MICHAEL N. SAWKA, RICHARD R. GONZALEZ, AND KENT 13. PANDOLF. Human thermoregulatory responses to cold air are altered by repeated cold water immersion. J. Appl. Physiol. 60(5): 154% 1548, 1986.-The effects of repeated cold water immersion on thermoregulatory responses to cold air were studied in seven males. A cold air stress test (CAST) was performed before and after completion of an acclimation program consisting of daily 9O-min cold (U?‘C) water immersion, repeated 5 times/wk for 5 consecutive wk. The CAST consisted of resting 30 min in a comfortable [24”C, 30% relative humidity (rh)] environment followed by 90 min in cold (5°C 30% rh) air. Pre- and postacclimation, metabolism (dM) increased (P < 0.01) by 85% during the first 10 min of CAST and thereafter rose slowly. After acclimation, AI was lower (P c 0.02) at 10 min of CAST compared with before, but by 30 min 2M was the same. Therefore, shivering onset may have been delayed following acclimation. After acclimation, rectal temperature (T,,) was lower (P < 0.01) before and during CAST, and the drop in T,, during CAST was greater (P < 0.01) than before. Mean weighted skin temperature (Tsk) was lower (P < 0.01) following acclimation than before, and acclimation resulted in a larger (P < 0.02) T,,- to-T,, gradient. Plasma norepinephrine increased during both CAST (P < 0.002), but the increase was larger (P < 0.004) following acclimation. These findings suggest that repeated cold water immersion stimulates development of true cold acclimation in humans as opposed to habituation. The cold acclimation produced appears to be of the insulative type.
cold acclimatization; cold acclimation; hypothermia; thermoregulation; catecholamines; metabolism; core temperature: skin temperature
has been reasonably well demonstrated. For example, Korean women divers who repeatedly dive in cold water have been reported to have a higher threshold for shivering (lower critical water temperature) than nondivers (16, 19). Also, Australian aborigines and South African bushmen who have lived many years exposed nearly nude to extreme low temperatures at night respond to cold exposure with little or no shivering and lower steadystate core and skin temperature compared with control subjects (13). Nonadapted humans respond to acute cold ’ Throughout this report the term acclimatization will refer to the exposure with marked shivering and elevated metabolic heat production (13, 18). The degree to which persons lacking a lifetime experience of cold stress are able to acclimatize to cold is not known. Furthermore, while cold acclimation procedures have been reported to produce altered responses to cold (3, 11, l&14,17, ZO), the extent to which such changes represent habituation (blunted response) as opposed to true acclimation remains unclear.
سازگاری با سرما، سازگار کردن با سرما، تقلیل درجه حرارت، تنظیم حرارت، کاته کولامینها، متابولیزم، دمای مرکزی، دمای پوست
وجود ویژگی سازگاری سرمایی در انسان ها موضوعی است که به خوبی تشریح شده است. برای نمونه، ان دسته از زنان کره ای که پیوسته در آب سرد شنا می کنند دارای آستانه لرزش بالاتری ( دمای آب کمتر) در مقایسه با زنان غیر شناگر هستند(16.19). همچنین، مردان استرالیایی و خانه بدوش های آفریقای جنوبی که سال های طولانی در معرض دماهای بسیار پایین شبانه زندگی کرده اند آستانه سرما و دمای پوست پایین تری در مقایسه با گروه های کنترل هستند(13). انسان های فاقد ویژگی سازگاری با تولید گرمای متابولیت و آستانه سرمای قابل توجه به سرما واکنش می دهند(13.18). میزان عدم دارا بودن تجربه زندگی و واکنش در برابر سرما مشخص نیست. به علاوه، در حالی که روش های سازگاری با سرما می توانند واکنش های متغیر در برابر سرما تولید کنند (3و11و12و14و17و20)، اما میزان ارتباط این تغییرات با خوگیری افراد در برابر سازگاری واقعی نامشخص است.