How much water should you drink? |
We’ve heard it for decades: Drink at least 8 cups of water a day. Not only can three out of four adults recite this bit of health wisdom, but many even feel guilty if they don’t meet the standard. However, this advice may be based on a misunderstanding. Some trace it to the 1940s, when the National Academy of Sciences published a recommended daily allowance of 1 milliliter of fluid for each calorie burned—a little over 8 cups for a typical 2,000-calorie diet. However, the statement also explained that most of this fluid could be obtained via the liquid contained in foods. Regardless, the 8-glasses-a-day dictum caught on. Today people frequently consume much more as they tote giant water bottles, buy super-size soft drinks, and follow programs that promise you can lose weight by drinking as much as a quart of fluid at a time. Also, those who choose to participate in such a diet may forget an important fact if they’re coffee drinkers: Caffeine is a diuretic – it encourages the kidneys to produce urine so effectively that it may contribute to mild dehydration. In moderation, there is little to worry about; but heavy consumers of caffeine may find a faster flow of fluids through their body, requiring a greater consumption of non-caffeinated liquids. In a 2000 survey conducted for Rockefeller University and the International Bottled Water Association, 2,818 adults in 14 cities reported drinking about 6 cups of water a day—a result that was presented as alarming evidence that Americans are becoming dehydrated. But if you include the sodas, coffee, tea, milk, juice, sports drinks, and alcoholic beverages these respondents drank, their average fluid consumption was 17.6 cups a day—enough to have you urinating every waking hour, even if you don’t have any problem with bladder capacity. More recently, a kidney specialist at Dartmouth Medical School searched the scientific literature for studies that might support the idea that people need 8 glasses of fluid a day. Not only did he determine that no such evidence exists, but concluded that the research that has been done "strongly suggests that such large amounts are not needed." Fluids and incontinence If you have an incontinence problem, the below tips might help improve your symptoms. Unless you engage in strenuous exercise or have a medical condition (such as a propensity toward forming kidney stones) that requires more fluid consumption: Aim for no more than 6–8 cups of fluid (from all sources) each day. Don’t drink more than 8 ounces at a time. Don’t guzzle. The faster your bladder fills, the more likely you are to feel urgency. Minimize caffeinated and carbonated drinks. Decrease or eliminate alcohol consumption. If you are thirsty because it is hot or you have exercised, don’t hesitate to drink water. |
david92003 发表于 2012/2/19 17:19
欢迎大家转载!
一天喝八杯水到底是哪个损人的主意?哈佛大学带我们追寻历史!