View Full Version : How much water do we need?
How much water do you think we need to sustain ourselves? A while ago I was giving it some consideration and when I looked about I came across a few different opinions. I know that in many case your weight etc can make a huge difference to how much you need to intake, as can climate and environment.
So, how much do you think we need, and how does that change as the environment changes?
I tend to drink whenever I can when I'm out (I keep a Swedish Army folding cup in the pocket of my smock at all times and use it when I want to drink) and I also drink whenever I am thirsty....I then keep an eye on the colour of my urine as an indicator of whether I need to top myself up.....
In terms of pints/litres per day I think it's so varied depending on climate, weather that particular day, what activities your doing and how your own body is made up compared to your mates...that whatever I work out I use one day will be different to what I use the next...
A lot of the book recommend different ammount and I think this reflects my sentiments above that only you can really judge for yourself.
Go for 10 litres a day and you can't go far wrong......or for that matter walk to far with the weight!!!! :rolmao:
I do leisurely backpacking in Florida (no hills) and stealth camp on one- or two-night trips.
In the summer, I need 3 liters per 24-hour period to feel okay. That water is used for drinking as I hike, and cooking meals and brewing tea or coffee in camp.
In the "winter" I can get by with 2 liters a day if I make sure to drink a liter before I set out.
If more is available, I'll use more. With the numbers stated, I feel like I have to account for every spoonful of water I use. When more is available, it takes away that stingy feeling of having to monitor my consumption.
The times I've tried to make do with less, I develop a headache.
i reckon 2/3 leiters will see me though a day easily with a bit of gentle walking milling round camp ect..
but when walking hard all day with a heavy pack i have been known to use 8 leiters just for drinking!
about 4pints is the normal for a day intake but I think that included what you get from food.
I often have a 3litre hydration system with me when I'm out and use that up if it's hot. A lot less if it raining
I think you start to feel thirsty when you loose 2% of your body waer but you should drink before this if your active. Also men can sweat a lot more then women but the quoted amount is up to 2litres a hour. I've drunk that much on a hot day on the bike but I don't really like all the figures as it changes so much.
If you drink to much you just pee more, if you don't drink enough your body wont like it.
as a basic measure during my working week I probably go for about 4 litres a day, if I am out hiking i can consume upto 10 litres a day ( an advantage of hiking in areas where the water supply is relatively safe) if just out for a walk in the woods, say 3-4 hours, I usually drink 2 litres split between straight water and a couple of brews.
As bamboodogy says though my urine is a good indicator if I need to consume more water.
I agree with tomtom and bambo in theory you should probably drink 8 to 10 litres a day while out and about.
However I can say with my hand on my heart that I have never ever drunk 10 litres (20 pints) of water in a 24 hour period. I know you get water from food but even including drinks before setting out and in the evening I rarely fill my 1.5L sigg bottle more than once a day ie. 3 litres.
I have never suffered ill effects from dehydration and I have hiked in the summer in the UK and south of Spain but again never more than 3 ish litres a day.
Am I doing it wrong :?:
one thing i noticed when doing ten tors that there is a lot of difference the ammount of water people need.. on a team of 6 people on the first day of ten tors we walked 36 miles.. i re filled my 2 liter platapus 4 times.. others on the team didnt drink nearly as much!
This article was published in 1999 so views may have changed.
Water: an essential but overlooked nutrient. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=9972188)
When giving iv fluids, we'd usually reckon on 3 litres a day for an average 70kg man.
If you are sweating due to exertion or heat, you would need to drink more of course.
Water is 70% of our bodies, give or take 10%. It's, by far, the most essential molecule for our body to work properly. Many body functions require water, from the elimination of metabolic waste to the dilution of many electrolytes that make chemical reactions possible. Slight dehydration (less than 2% of total water mass) already has great impacts on our general well being. Many things like daily fatigue, constipation, dry skin or joint inflamation can be helped a lot just by drinking more water... Thus I think that what many people miss to be perfectly happy is one more liter of water a day.
As already mentioned, water intake is something personal. I'm a big guy, and I personally drink a lot when hiking/jogging in hot climates. Up to a liter every hour. At rest in a cool place, my water cunsumption can go down a lot.
Thirst is not a good indicator for dehydration, as is actually is a pretty complex phenomenon. But usually when you're thirsty, you're already dehydrated to about 2% of your total water mass. In other words, you should drink before being thirsty, and adapt your water intake according to how much water you spend.
A basic survival concept is that our stomach is our best canteen...
Another good one is to watch your urine. It should be clear. Whenever it turns darker, drink up...
For myself, for winter day hikes I carry 2 nalgene bottles. I often come back with one half full, as in the cold the peripheral vasoconstriction raises blood pressure. To keep blood pressure level, your kidneys go to work and reduce blood volume by producing urine... Because of this, you basically excrete 1-2 liters right after going from a warm to a cold-adapted body. Whatever you drink is eliminated during this period, so drinking is pointless. However the "clear pee" rule still stands, as during that time your urine is usually clear and plentiful. Once you've stopped eliminating this excess water, though, you must resume your water intake and keep on drinking regularly... And when you come back home, as your peripheral blood vessels come back to normal, your blood volume is suddenly too low, and your blood pressure drops a little. You have to replenish that volume by drinking 1-2 liters of water... the same 1-2 liters that were excreted in the first hours in the cold...
Our bodies can´t take in more then about 2 cl of water per hour. So the most important thing is to drink little but often. If you drink too much you will pee out all your witamines and minerals and will get a problem that way instead.
If hiking or walking for a several days a waterbladder like the camelbak or platypus is highly recommended because you will then little but often.
I don't know where the 10 litres of water a day came from, but I think that this would be a very high level of water to be consuming. I have done a bit of research, and a British soldier would be expected to drink 10 litres a day if he were in NBC kit carrying out a moderate workload in a 25-30 degrees C enviornment.
Also, I have been told that drinking a large quantity of water could flush a number of essential salts out of your system, so if you do drink such a high quantity of water, you need to replace the salt by supplementing your food or water consumption.
But I used about 5 litres a day when I was in Oman during the summer, and very rarely drink more than three litres a day, probably not even 2 litres.
But everybody's different!
Just to exist, no movement or anything else we will lose on average at least 500ml of fluid a day through respiration and perspiration in a temperate enviroment.
As an absolute minimum you will require 1.5-2 litres of fluid, in a tropical enviroment to stay tip top you may require 15-20 litres.
Our bodies can´t take in more then about 2 cl of water per hour.
Sorry to disagree here, Viking. I've read data of an average of 0,8 L (ie 80 cl) of water absorption capacity (French book sorry: Jean-Louis Étienne, Médecine des Randonnées extrêmes, oct. 2004). It's not me saying it. It's a doctor and famous extreme hiker who does... His numbers correlate my personal experience.
I have to agree, though, that you better drink that in small ammounts, regularly throughout the day.
I've never thought of it as how much water I need. I usually fill up when I need, I guess I fill up my 1 litre bottle about 3 times a day during the walk, then another litre at camp.
I have been from bottle's to platapus' to bottle's again. :roll: Purely because I find them easier. Far too much hassle to keep clipping the hose to your pack, trying to fill up a flexible container in the stream (I always use white water) and stopping the mouthpiece from dripping. However a friend of mine uses a 4(?) litre plat' to fill up at camp, useful if we are far from the river. :biggthump
I've only every exceeded 10liters a day when I cycled about 55miles on my bike in about 30-32 degrees off road with about 14kg of kit
I guess I was in shorts and T shirt unlike in the army but even so.
I guess I've done uphill cycling at mid day and got through 3.5liters in 1.5 hours
I then used 0.5 liter for all the way home and was fine. I wasn't pedling and had lots of wind chill factor but thats in the same temp (took about 60minutes)
I normally drink 2 litres from the time I get up in the morning until 8:00pm. I find that my urine runs clear with that amount of intake. If I'm hiking or working up a good sweat, or it's one hot and sweaty day and I'm idle, I up that to around 3 litres and sometimes more. While living in the Sierra Mtns at the 6000' elevation, I continued to drink about 2 litres per day during the cold and snowy winters. Course, back then it was alcoholic beverage (scotch whiskey), coffee and about a litre of water.
Aside from the quantities of water we have a debate on the time and frequency of intake itself. I subscribe to the old adage " carry water in your belly, not in your canteen." True, a large single intake can flush vital salts. It also flushes a host of nasties out too. Establishing 100% hydration AND supplementing vital salts, minerals and electrolytes at the start of any outdoor adventure puts us "Shipshape in Bristol Fashion." There are to many personalities promoting some grim ethic of sipping small quantities, or only at dawn or dusk in some rediculous re enactment of Beau Gest.
The most I have ever used in one day in the bush was 8 liters, some of that was for cooking and a little for washing off. It was about 100 and I was exerting myself in the sun. I also sweat like a horse.
I make it a rule to always carry enough containers to fill up for a full days supply at a single source. For me that means five liters minimum. I don't often carry that much water but I want to be able to. My typical load is one canteen and two 2-liter platypus bags. I also carry a reserve five liter water bag rolled up in my gear. These are light and take up very little space but allow me to carry or cache an extra day's supply.
In the tropics I also carry salt and sugar or oral re-hydration ready-mix from the local pharmacy. It is amazing to me how a little rest, a little salt/sugar, and alot of water can perk me right back up. Mac
Don't know how accurate it is but you might want to play around with this. (http://www.csgnetwork.com/humanh2owater.html)
Great, except I'm too heavy for the calculator :rolmao:
When I'm thinking about it through the day I try and down about 3 lt water a day, when I'm sweating a lot that's double. It's weird how when I'm at home I really don't like water very much, unless it's really cold. When I'm out and about it's a different matter, I'll just drink it and it tastes good :roll: :biggthump
Great, except I'm too heavy for the calculator :rolmao:
Cut your weight in half and multiply your results by two. :biggthump
Great site. I saved a bunch of pages there regarding the weather. Mac
Cut your weight in half and multiply your results by two. :biggthump
It's 2 in the morning here, I need to go too bed :roll: