I’m not making these numbers up, lol. See the recommendations of the Institute of Medicine. See the Mayo Clinic recommendations. See National Institute of Health. Relying on thirst to determine whether you are adequately hydrated is, if you will excuse the expression, “piss poor”. By the time you feel thirsty, you are already 1-2% dehydrated which is significant. The commentaries advocating using thirst to regulate hydration are looking for a simplistic convenience since nobody really wants to track fluid intake and most people are probably not very good at it. And if you are physically active, your needs are even more acute. But keep in mind that these recommendations are for total fluid intake, about 80/20 from beverages and food sources. And like any generalized recommendations, specific individual needs will vary.
That last link references a doc from the Institute of Medicine, which all these other sites seem to be getting those numbers from. On the “water” page of that document, it says
Millions of years of evolution have made thirst a pretty effective mechanism.
Is being down 1% of the water in your body really that significant? Perhaps it is for peak athletic performance, but since I am not a serious athlete this is not really relevant. For you it may make a difference.
We don’t tell our cats and dogs (or any animal) when to drink, or try to make them drink on a schedule at a certain volume. Why do humans have to do this?
I like water, drink a lot of it–somewhere around 6 or 7 twelve ounce glasses every day–and certainly feel better when I drink plenty of water. Of course, it’s Portland’s Finest Tap, which is really good water, without fluoride. Bizarrely, while fluoride is generally considered to be a major public health benefit, the only factual problem with fluoridation is a tiny increase in the incidence of the bone cancer I had. I do use fluoride toothpaste.
I do, however, sweat profusely when I run, even when it’s cool out, which may be part of my fondness for water.
I’m now two-and-a-half weeks into running every day. It’s a nice routine and I definitely feel stronger, although I don’t know if I’m any faster. I did a set of stairs today (25 flights) that normally leaves me toasted and felt pretty good. I also went for a bike ride with a friend… which was great until it started hailing on us. Little tiny hailstones though, so they just stung.
I don’t like coffee, so I try to drink tea or iced tea for my morning caffeine- which I DO like to have. I probably drink 3 diet colas a week, which is a reduction. I don’t get sweet cravings from artificial sweeteners, but I eat more sweets than I should anyway.
I’m flying from Dallas to California tonight. I am going to be very tired.
There is nothing inconsistent in what you have cited with regard to my original post. They say the same thing. As to what AI vs RDA is all about, it’s the difference between having enough data to make specific fixed recommendations for defined demographics vs setting adequate intakes that are known to be sufficient for bodily functions.
As to simply drinking when you are thirsty? It doesn’t assure adequate fluid intake for most people because they don’t really listen to their bodies the way our cats and dogs do or don’t generally have access to fluid on demand as we go about our busy days the way our pets do unless we have water bottles at our desk or are willing to repeatedly disrupt our work to get cups of water from the water fountain down the hall. “Drinking when you are thirsty” is really a behavioral concept that is subject to all sorts of vagaries and factors that interfere with adherence. And how do you really define thirsty? It’s often a question of perception. When are you really “thirsty” enough to stop what you are doing and get that drink. I would tell you to keep a log of how much you drink based on thirst but the mere act of logging it would skew the results. Instead, next time you are at work, every time you are thirsty and get a drink, throw the cup in your office trash can. Count the cups at the end of the day. I’ll bet you consume far less than you think. That’s why I think setting an objective measure is a better way to assure sufficient hydration. And by the time you feel thirsty, you are already dehydrated. If you have a nice cushy office job in a climate controlled environment, probably won’t make much difference. But if you have a physically demanding job, are in a temperature stressed environment or are an athlete, by the time you feel thirsty, you are likely to be compromised.
But hey, you do what you want. Your body, your choice. Me, I’ll rely on my experience in the field with myself and with others.
I feel like most people are not in these categories. I’m certainly not - I sit at a desk in an overly-cooled office, and though I work out I have no illusions of being an athlete. Of course if you are doing something that is causing you to lose large quantities of water it doesn’t make sense to wait until you feel thirsty to re-hydrate. And even the pros mess this up - you hear all the time about football players getting I.V.s at halftime because they are dehydrated.
So you are consuming a gallon of fluid per day? That much fluid would make me feel terrible.
Look, I’m not trying to be argumentative or contentious (so there’s no need to get all passive-aggressive), and if I am coming across that way I apologize. We are just having a discussion. But I have a mistrust of most “official recommendations”. You can find studies to back almost any side of an issue. For a few decades the “recommendation” was avoid fats and get 60% of your calories from carbs, and where did that get us.
This is interesting and got me thinking as to how much water I actually drank today. I don’t really think about recommended quantities of water, etc. I had two liters of bottled water and three 16 ounce tumblers - so around 114 ounces. Add some coffee and a La Croix water (for a treat) and I’m sure I had a gallon of fluids. That’s pretty typical for me. Physically I feel much better now that I’m drinking more water than when I was drinking a lot of diet soda or “reduced calorie” or “diet” juices.
I am a very salty sweater - in a warm weather strenuous workout, my face becomes almost salt encrusted. For me, the more water the better. I ran close to an hour this morning, but nothing too demanding; it was hot and humid and I was very sweaty. Bring on the water.
No offense taken and no need to apologize notrichenough. I don’t necessarily subscribe to “official recommendations” either simply because they are “official recommendation”. In this case, however, I think the recoomdndations are pretty spot on for a variety of reasons. And keep in mind, it’s not drinking a gallon of fluid per day for men. It’s more like 3 quarts of drinking and a quart of water from the food we eat. Morever, for people who frequent this forum, who for the most part are regular vigorous exercises, waiting until you are thirsty isn’t going to cut it. I don’t need a “study” or “official recommendation” to tell me that. I’ve personally experienced and observed the impact of not making a conscious effort to systematically rehydrate. What would be interesting is to see a well controlled study that actually measured the amount of fluid consumed by someone who drank on demand only when thirsty and who also consumed fluids at meals, compared the volume to the recommended amounts and measured actual hydration levels.
And btw, the problem with the emphasis on carbs in the past was that it was used to promote the consumption of refined flours, added sugars, and processed carbs which is what led so many of the health issues that are prevalent today. In the absence of various metabolic medical conditions, today’s USDA recommendations of 50% carbs from whole grain foods and fruits is pretty much on the money for most people. It’s the low carb proponents who demonize healthy carbs that are relying on suspect “science”.
“What would be interesting is to see a well controlled study that actually measured the amount of fluid consumed by someone who drank on demand only when thirsty and who also consumed fluids at meals, compared the volume to the recommended amounts and measured actual hydration levels.”
Fascinating article dmd77. Great find. Interesting findings about impact of % dehydration. “Shocking” recommendations on fluid intake - a bit more than 3 quarts for an average male who is sedentary in a temperate climate. Close to 5 quarts for that same male who is physically active or in higher temperatures. Women a bit lower. Kinda falls right into line with the sources I cited earlier ;). One thing I didn’t see discussed is the impact of dehydration on blood plasma volume. Here’s an article that mentions that as part of a more comprehensive discusion of hydration and sports performance.
The heavy rain ended last night so I was able to go out and run this AM. Ran another mile then intervals for an additional 2.5 miles. I am now actually looking forward to this!
Had a nice conversation with one of my yoga teachers before yesterday’s class. She was asking me about my 5K as she is very into running. I was surprised when she told me that it took her a year to run 3 miles without stopping as she is much younger and in great shape. But it all goes to show that it is not easy for a lot of us and it takes patience and hard work.
H, S and I are driving to Toronto tomorrow. I plan a lot of walking and there is fitness center in the hotel. And we are booked on a food tour
20 degrees cooler this morning for my run than yesterday. Unfortunately, I did not have a good route. I’m in Costa Mesa, but surrounded by freeways and busy roads. I ran on a sidewalk, and it was very early so I was OK. Got into a big industrial park, which was safe but not very pretty. Eked out 4.3 miles. I don’t do Pacific time very well, so was awake at 3:30 am.
For folks who like fizzy drinks, I highly recommend Talking Rain naturally flavored, unsweetened water. My favorite is Lime. Plus, I like to support local businesses - they are based just east of Seattle.
Water, like in H2O, is pretty much the only basic “food component” that no one has declared bad for our bodies. While there is disagreement as to how much we should be drinking, no one has said we have to strictly limit it (like carbs, sodium, fats, and even protein). Plus, it helps to keep the weight in check by making the you run for the bathroom and keeping your belly from asking for too much food.
It’s going to be a long day for you, MOWC. Today is a rest day for me, although I don’t feel like I need it. I usually do Pilates or the like but wanted to see how tomorrow went without working my legs the day before. Tomorrow is 165 minutes of MAF running and I’ve really tried to think through a route where I can do a better job controlling my HR. I am also trying to do a better job with eating today; this morning I mixed Vega powder with cinnamon horchata and some huge organic strawberries for a smoothie.
Bunsen, there is, though, the concern about hyponatremia for those who are very active or are subjected to heat extremes and drink so much water without any form of electrolyte replacement as to create sodium and water imbalances at a blood serum and cellular level. Can be a very real problem with endurance athletes. Actually resulted in some widely reported deaths among young athletes a few years back. Here’s a site that will appeal to you as a scientist: https://www.hyponatremiaupdates.com/
The take away: if you are involved in physical activity that causes profuse sweating, make sure to replenish electrolytes as you hydrate. Sports drinks, gels, energy bars. My favorite on long hot bike rides is a product called Endurolytes made by Hammer Nutrition. They are electrolyte capsules that I take at periodic intervals during the ride. No bloating or GI problems from sugary energy drinks, no overeating of bars. I also supplement with Cliff Bloks for both an energy boost and electrolytes. With these products, I am able to drink just water to hydrate, use energy bars with real food ingredients for carb replenishment and use these other products to address electrolyte replacement.
