字幕列表 影片播放 已審核 字幕已審核 列印所有字幕 列印翻譯字幕 列印英文字幕 Water is amazing! It's necessary for life to exist, makes you healthier, and it's incredibly refreshing 水真的令人驚艷! 水對生命的存在是必要的 讓你更健康 而且讓人精神抖擻 -especially after an intense workout. But is water intoxication a real thing? 特別是在劇烈運動後 但是水中毒是真的嗎? Can you drink too much water? 你真的可以喝太多水嗎? We're often told to drink around 8 glasses of water a day to stay healthy, but the honest truth is that this specific number is somewhat arbitrary, and no scientific research exists to support it. 我們說 人一天要喝八杯水來保持健康 但事實上這個喝水的量是沒有根據的，科學研究也無法支持這個論點 Regardless, we know water is incredibly important; in fact, every organism we know of requires water to survive. 即便如此，我們還是了解水非常重要；事實上，每種生物都需要水才得以存活。 Not only does it help the human body to bring oxygen and nutrients to the cells, regulate body temperatures and aid metabolism, but it flushes waste out of the body. 水不只幫助人體攜帶氧氣及養分到細胞中， 平衡體溫以及幫助代謝，它也會排泄掉人體的廢物 Sweat out too much during a sporting event, and you'll start to feel a bit woozy. 運動時流失過多汗水 Three days without water, and you likely won't survive. 你會感到頭暈目眩 三天沒喝水 你可能無法活下去 So how could such an essential substance hurt us? It all comes down to the cellular level. 所以水 這個物質必需品怎麼會傷害人體? 這要從細胞層面說起 The water you drink has very few electrolytes in it - things like sodium or potassium - especially compared to your cells. 比起身體的細胞，你喝的水裡面只有非常少的電解質，像鈉或鉀 The electrolytes in your cells allow your muscles and nerves to work properly, 你細胞內的電解質能使你的肌肉跟神經順利運作 and help to control blood pressure and blood volume. Without them, your body 電解質也能幫助控制血壓以及血液濃度 沒有它們 cannot function. Now normally, the difference in the electrolyte concentration inside and 你的身體就無法運作 正常來說 細胞內外的電解質濃度 outside the cell wouldn't pose a problem, because your kidneys flush out any excess water; 不會造成太大的問題 因為你的腎臟會排除多餘的水分 however, the kidneys can only excrete fluid at a certain rate. This means that consuming 然而 腎臟只能排泄一定比例的水分 這就表示 a lot of water in a short period of time creates a large concentration difference. As a result, 短時間內喝太多水 會造成濃度很大的變化 water is drawn into the cells in an attempt to dilute the concentration and even out the 因此 水就會被細胞吸收並降低體內電解質濃度 proportion of electrolytes, and this causes the cells to swell. 使細胞內的電解質平衡 而這會造成細胞膨脹 The problem is, unlike other parts of your body, the brain literally has no room inside the skull for these newly plump cells. 這問題在於，不同於身體其他部位，腦部並沒有多餘空間容納這些剛膨脹的細胞 This results in extreme headaches and confusion, 這會產生極度頭痛 頭暈的現象 leading to seizures, comas, respiratory arrest and even death. 造成癲癇發作 昏迷 停止呼吸甚至死亡 So should you be worried? Not likely! Cases of water intoxication are very rare, though 那你應該要擔心嗎? 其實不用! 水中毒的案例非常少 they do happen in extreme circumstances. Close to 1/6 of marathon runners develop mild 雖然在極少數的情況下會發生 大約有1/6的馬拉松選手 cases in their careers, with all endurance athletes at a higher risk. This is because 在其生涯中發生過輕微症狀 所有耐力賽的選手也是高危險群 under the extremes of athletic stress, the body attempts to conserve water. So not only 因為這種運動壓力的極限當中 身體會自動儲存水分 are you taking more water in, you're peeing less out. 所以你不只會喝很多水 也會減少小便次數 Science says, though you're not likely to suffer from water intoxication, you should 科學指出 雖然你不太可能水中毒 drink to your thirst - it's the best indicator! 但是你渴了就應該喝水 這是最明顯的缺水警示囉! Don't forget: we have a new video out every day during the Olympics. 別忘了! 我們在奧運期間 每天都有新影片出爐 But if you can't wait, head to cbc.ca/olympics/ScienceSays for more. 如果你迫不及待 直接到 cbc.ca/olympics/ScienceSays 搜尋更多影片 Keep asking those burning questions with the hashtag ScienceSays, and subscribe for more awesome science videos! 請繼續以 #ScienceSays 發問 然後訂閱更多更棒的科學影片吧!