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喝水比你想像中重要！不能不知20個喝水的好處

2023/02/17

水是人類生存的必要物質，約佔人體重量的50-70%。1 建議每天喝至少6至8杯 (每杯約240毫升）水或流質飲品，例如清湯、牛奶等。2

一天要喝8杯水才足夠？1,3,4

這只是一個參考的準則。每個人每日需要攝取多少水分要視乎不同因素，例如性別、年齡、體重、氣溫環境、個人活動量等因素而決定。天氣炎熱、運動量大、發燒或肚瀉等情況都會令身體流失更多水分，我們則需要補充額外的水分。另外，喝水不是補充水分的唯一途徑，我們每天亦會從食物中攝取約兩成水分。在一般情況下，不用太刻意強迫自己每天喝8杯水。

喝水指引公式：

每磅體重需大約15毫升水，例如150磅（約68公斤）的人士，每日需要喝約2,250毫升水（15mlx 150磅 = 2,250 毫升 )。

20個喝水的好處

1. 維持正常血液循環3 充足的水分令身體血液循環改善
2. 大腦更靈活3 水分佔大腦重量約75%，充足的水分有助維持大腦運作。研究發現輕微脫水有機會影響認知功能
3. 運送營養物質5，6 良好的血液循環能讓營養素和氧氣可以順暢地運送至各個器官
4. 緩解頭痛7，8 身體脫水可能會令大腦流失水分，牽引腦膜或刺激腦神經而誘發頭痛
5. 減低患上慢性疾病的風險9，10 長期處於輕微脫水狀態與高血壓、高血糖、糖尿病等多種慢性疾病有關
6. 改善心情11 身體含水量低會影響心情，脫水可能會引致疲倦和誘發暴躁的情緒
7. 維持膀胱的健康9，12 補充足夠的水分可確保每日排尿頻率正常，減少尿液中的代謝物和潛在致癌物停留在膀胱內的時間，達到保護膀胱的作用
8. 有助減少熱量攝取11，13 飯前喝水有助降低食慾，減少正餐進食的份量，從而減少攝入過多的熱量而引致肥胖
9. 幫助消化和改善便秘3，5 幫助腸胃蠕動，改善便秘問題
10. 降低泌尿道相關疾病9 能降低患上如尿道結石或發炎等泌尿科問題
11. 預防/舒緩腎結石3，12 身體缺水會增加腎結石的風險及復發機會
12. 有助皮膚健康3 充足攝入水分有助防止肌膚乾燥和形成皺紋
13. 維持身體機能運作14 人體的每個器官系統都需要水分才能正常運作
14. 加速新陳代謝11,13 足夠的水分攝入可增加代謝率：增加攝取500毫升水分可將代謝率提升30%
15. 潤滑關節 / 緩解關節疼痛3,5,15 關節之間有軟骨連接，而水分佔軟骨組織重量的80%。軟骨內的水分充足可形成潤滑關節及緩衝作用，減少體重和運動帶來的衝擊
16. 改善運動表現11,16 身體輕微脫水亦會令運動耐力、力量及動力下降
17. 有助口腔健康3,9 攝取充足水分可確保口水正常分泌，有助維持口腔和牙齒健康
18. 促進營養吸收11 有助分解食物中的維他命和礦物質，能被身體更容易吸收
19. 減低心血管疾病17,18 可以降低心臟衰竭的風險。而人體缺水時，心血管調節功能會受影響
20. 調節體溫5,11 天氣炎熱時身體會通過排汗來降溫，此時補充流失的水分，可達到調節體溫的效果

缺水有什麼症狀？19,20

  • 口渴
  • 疲勞
  • 舌乾
  • 皮膚乾燥
  • 排尿量減少
  • 尿液顏色偏深，並帶有明顯的氣味

 

如何增加喝水量？21,22

  • 隨身自帶水樽，隨時隨地補充水分
  • 用餐時用清水代替高糖飲品
  • 若覺得清水淡而無味，可加入青檸、檸檬、青瓜等改善味道
  • 若不喜歡喝清水，可選擇多喝無糖果汁或蔬菜汁
  • 多吃高水分含量的蔬果，如西瓜、青瓜、生菜和芹菜等

 

正確喝水小貼士：1,14,23-25 

  • 運動前補充480-600毫升清水
  • 若運動時間超過一個小時，可在運動期間每20分鐘補充90-240毫升清水／含鈉的運動飲品。進行長時間強烈運動後，補充含鈉等電解質的飲品和水分同樣重要。留意：流汗過多時，不應只是補充水分而忽略補充鈉，否則容易導致低血鈉（Hyponatremia）。
  • 睡前兩小時盡量不要喝水或控制喝水量，以免夜間起床如廁擾亂睡眠
  • 當尿液變成透明無色，表示攝取水分過多，應適當減少喝水
  • 早上醒來、運動或流汗、生病或頭痛時需要多補充水分。但如果飲水過量，腎臟便無法及時排出多餘水分時，血液中的鈉含量被稀釋，便可能引發頭痛、疲勞、噁心、抽筋等低血鈉症的症狀，嚴重時可出現昏迷

參考資料:

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