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台灣登山論壇
咖啡因對心臟的影響
2006/5/18
朋友email了一篇路透社的文章 (原文如下). 大意是說在運動前, 最好禁喝任何含有咖啡因的飲料. 因為咖啡因會導致流入心臟的血液大量減少, 尤其是在高海拔, 更為嚴重 (降了39%). 對健康的人來說, 或能勉強忍受, 但對冠狀動脈有問題(例如冠狀動脈心肌哽塞) 的人來說, 這是有害的.
有時我在想....很多人(連我自己也是) 根本不知道自己的冠狀動脈是否健康.....有人有更多資訊嗎???
Don't Drink THIS Before You Exercise
If you're planning to exercise later today, make sure you stay away from beverages containing caffeine.
Drinking just two cups of coffee before exercise decreases blood flow to the heart while you're working out, and this reduction is most pronounced at high altitudes, reports Reuters of new research from University Hospital Zurich.
Healthy people may be able to tolerate the reduced blood flow, but it could be especially harmful to anyone with coronary artery disease.
The study: Led by Dr. Philipp A. Kaufmann, the team used young, healthy adult volunteers to test the effect caffeine had on blood flow to the heart both at rest and after exercise. They ran the tests at normal oxygen levels and then simulated the low oxygen levels that occur at high altitudes. Cardiac blood flow was measured at a baseline and then 50 minutes after the volunteers ingested 200mg of caffeine, which is about the equivalent of two cups of caffeinated coffee.
The results: At normal oxygen levels, caffeine had no effect on resting myocardial blood flow, but at low-oxygen levels, resting myocardial blood flow was significantly increased by caffeine. However, during exercise, caffeine caused a significant decrease in blood flow to the heart at normal and low oxygen levels. Specifically, caffeine caused the myocardial flow reserve to drop off 22 percent at normal oxygen levels and 39 percent at low oxygen levels, reports Reuters.
The takeaway: Skip the caffeine before you get on the treadmill.
The study findings were published in the Journal of the American College of Cardiology.
有時我在想....很多人(連我自己也是) 根本不知道自己的冠狀動脈是否健康.....有人有更多資訊嗎???
Don't Drink THIS Before You Exercise
If you're planning to exercise later today, make sure you stay away from beverages containing caffeine.
Drinking just two cups of coffee before exercise decreases blood flow to the heart while you're working out, and this reduction is most pronounced at high altitudes, reports Reuters of new research from University Hospital Zurich.
Healthy people may be able to tolerate the reduced blood flow, but it could be especially harmful to anyone with coronary artery disease.
The study: Led by Dr. Philipp A. Kaufmann, the team used young, healthy adult volunteers to test the effect caffeine had on blood flow to the heart both at rest and after exercise. They ran the tests at normal oxygen levels and then simulated the low oxygen levels that occur at high altitudes. Cardiac blood flow was measured at a baseline and then 50 minutes after the volunteers ingested 200mg of caffeine, which is about the equivalent of two cups of caffeinated coffee.
The results: At normal oxygen levels, caffeine had no effect on resting myocardial blood flow, but at low-oxygen levels, resting myocardial blood flow was significantly increased by caffeine. However, during exercise, caffeine caused a significant decrease in blood flow to the heart at normal and low oxygen levels. Specifically, caffeine caused the myocardial flow reserve to drop off 22 percent at normal oxygen levels and 39 percent at low oxygen levels, reports Reuters.
The takeaway: Skip the caffeine before you get on the treadmill.
The study findings were published in the Journal of the American College of Cardiology.
所有回覆
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非常感謝 sytt(bluetongue) 兄的資訊. 不曉得喝茶是否有相同的顧忌? 該篇醫學原文可在下列網址找到. http://www.zihp.unizh.ch/new_papers_cms/Namdar_Kaufmann_JAmCollC_06.pdf
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呵呵呵...小弟也來插花提供一下自己的經驗。爬山與爬樓梯的心境及速度都不太一樣，爬山通常是長程而且心境較為愉悅，一般我們都採取平穩的步伐前進，你若在爬山過程中喝點咖啡或茶，沒有注意比較的話，有時還感覺不太出來，但是你若有爬樓梯經驗的人(如新光登高或101大樓登高)，爬之前若喝了咖啡或茶，保證比沒喝時更氣喘如牛，小弟經常作爬樓梯練習(30樓)，屢試不爽，故都儘量避免在爬樓梯練習前2至3小時內喝咖啡或茶。這實驗很容易做，找個大樓或階梯式的登山步道試試就知道了，呵呵呵...
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在網上搜尋了一番, 得知不僅茶飲料中含有咖啡因, 可樂、提神飲料、奶茶及巧克力等都含有咖啡因. "如果以等量咖啡和茶比較，可樂所含咖啡因約為咖啡的四分之一、茶的二分之一", 請參考董氏基金會或消費者基金會的調查報導, http://www.tgs.com.tw/news931101.htm http://www.consumers.org.tw/unit412.aspx?id=559 此外, 該篇國外醫學研究係以口服 200 mg(毫克) 的咖啡因作試驗, 200 mg 咖啡因是喝多少咖啡所攝取的量呢? 如果以咖啡因含量 200 ppm 的飲料為例, 喝 1000 cc 是相當於攝取 200 mg 的咖啡因. 如果咖啡因含量升高為 400 ppm, 則喝 500 cc 就有 200 mg. 如果咖啡因含量高達 800 ppm, 則只喝 250 cc 就有 200 mg. 另外, 該篇論文中以踩腳踏車時呼吸氮氧比為 8:1 的空氣來模擬海拔 4500 公尺高度時的稀薄氧氣供應, 與實際情況有點誤差, 如果考慮氣壓低的影響, 說不定會更嚴重.