Winter Hiking & Dehydration

[JoeCedar]

Am I the only one who notices that dehydration is more severe (and potentially more serious) on winter hikes? On longer non-winter hikes I usually try to carry two liters and a pump, so I have an unlimited supply with reasonable weight (and I really try remember to drink it). I have found that I feel much better at the end of the day, and even the next day after a long hike, when I have kept my water intake up. Along with the water I have food, snacks, peanuts, etc., to replenish lost salt. Winter hiking, however, presents several issues with carrying and drinking an adequate amount of water. Here are some of the reasons I can think of:

Hikes are often longer, up to 12 hours or more

Greater perspiration (difficulty controlling clothing/ventilation) and greater exertion (deep snow, breaking trail, etc.)

Heavier pack with extra clothing, crampons, winter gear, etc.

Inability to use a water-purifier pump for refills

Don’t want to carry 4 Liters or more, due to weight

Water gets cold, even freezes, and is not pleasant to drink (chilling)

Food consumption tends to also be reduced along with water

Bottle “parkas” take up more space and don’t work very well

Vacuum bottles (mostly stainless steel) perform well, but add weight (I have a 0.75 L bottle that weighs 1.1 lb) and take up pack space


So does anyone have an answer to the dehydration problem on long winter hikes? Tolerate it? Just carry 4 liters or more, and keep it from getting cold? Do shorter hikes?

[billandjudy]

We find just the opposite--We carry the same as warm weather but drink less. Yesterday we both started w/ 2L and both came back w/ at least a L apiece after 8.75 miles and 3000 vert. Judy drinks less than I do--she never sweats--I think it's a Dominican thing :D

[ADKJack]

I have found that winter hiking does require more hydration. The winter air is dryer than the summer, less humidity. Tend to breathe through my mouth more due to nasal congestion also drys one out. Even on 12 + hour hikes I carry two nalgenes and a pump but have not used it yet. This is what I do.
A freind I know once told me the key to not needing a lot of water is not to sweat. Easy for him to say he climbs these hills everyday, but there is a lot of truth to that. I have gotten much better at dressing for the hike, I make sure that I am cold at the car and then adjust clothing at the first mile if needed.
I mix my water with about 1/3 powerade. I keep one nalgene on my hip in a insulated carrier and the other I fill with the same mixture as the other but I use hot water and put it inside a wool sock towards the middle of my pack, keeps it from freezing over a longer time. Also splash guards on the bottles help keep me from gulping more liquid than I really need.

[Neil]

To my delight I consume way less water in winter than in summer. (My summer record is 8 liters in a day.) I sweat profusely in all seasons but much less so in winter. To help with moisture management I start my hikes in a lightweight longsleeved shirt under a very light and thin wind breaker, even in the coldest weather. I carry 2 Nalgenes and if it's going to be a cold day I fill them with boiling water in the morning, place in water bottle jackets and bring to the to the trailhead in a small cooler. I wear one of the Nalgenes on my person and carry one in the pack, wrapped in some clothes. To encourage drinking I have tried flavouring and sweetening the water but when cool and damp I have found that sucking back pure hot water can be quite blissfull.

I usually drink a lot of water while driving to the TH. That seems to help me but it might not be practicable for those who live a mere 10 miles from the TH. :D

[AlpineSummit]

I need more water in winter since in the other months I just depend on coffee or beer.
A couple of things I do:
First I try to pre-hydrate. I start the day before drinking extra fluids and drink right up to the start of the hike. I usually drink something right before the hike starts.

HHHmmm, looks like I messed up that quote a bit - DUH.
Sorry Rik.

Anyway:
That 1st part of what he said is the most important part; drink on the way to the trailhead and even some extra the day before the hike.

In my case, if I don't arrive at the trailhead already in need of a tinkle; I didn't plan right. I try to drink an entire nalgene's worth on the drive over.

[DSettahr]

I mix my water with about 1/3 powerade.

I find that adding any kind of powdered drink mix to my water in the winter helps to keep it from freezing. And even when it does freeze, it turns into slush rather than freeze solid.

First I try to pre-hydrate. I start the day before drinking extra fluids and drink right up to the start of the hike. I usually drink something right before the hike starts.

Same here. I usually bring an extra liter of water in the car with me on my way to a hike, and try to have it finished before I leave the trailhead. I do end up having to stop and pee about 5-6 times in the first hour or so, but I start out the hike feeling a lot better and more energized.

In general, I've found that I dont need to drink as much water in the winter as I do in the summer. I dress in layers, and try to always be at that perfect temperature where I am warm but I do not sweat. Not only does this keep me better hydrated, but it also keeps my clothing dry, another important consideration in the winter.

[lumberzac]

I’m sure I’m not the only one that has had this happen, but I find I have to force myself to drink water when hiking in winter conditions. Something about the cold makes me not want to drink even if my body needs it. This isn’t good considering dehydration can make one more susceptible to frost bite and hypothermia. I do similar to Rik and try to pre-hydrate before the hike. When I hike in winter someone in my group always has a stove for melting snow for water should we need to; it hasn’t happened yet. I don’t carry a water filter as they freeze and then don’t work, but I do carry some iodine tablets. One thing to keep in mind is iodine take much longer in winter to treat the water.

[Joe H.]

The track and cross country coach in my has me arriving at the TH for all hikes in a hydrated state. In winter this is especially important, as others have pointed out, since dehydration increases frostbite and hypothermia risk. I carry about the same amount of water for winter as summer - generally two liters for a shorter day (I can go about 10 miles on 2 liters), 3 liters for longer ones. In the winter I also carry a thermos with some hot water, but I generally do not use that - it's carried more in case someone in the group needs some warming up. Another alternative, is a small stove, pot, fuel combo. Mixes in drinks will keep water from freezing. I tend to start with hot water in my bottles in winter to keep them liquid longer. I have never used anything but some old socks for extra bottle insulation. I find that buried in the pack is fine, even without anything extra around the bottles. I put the bottles in upside down so the tops do not freeze on.

Filters are tough in the winter as Lumberzac mentioned, and chemical treatment less reliable.

[AlpineSummit]

Filters are tough in the winter as Lumberzac mentioned, and chemical treatment less reliable.

Yeppers, and falling into a brook is both possible and very dangerous.

[lumberzac]

Something I did not mention earlier. For those that bring a stove and pot to melt snow for water, make sure you have some water to mix in with the snow to start otherwise you will have a tough time getting any water out of the snow; it will melt and then boil away leaving you no water. I’m sure you all knew that already though.

[mudhook]

Not having a tube to drink from in winter, I tend to cut back on water and then feel it during and after the hike. I constantly have to remind myself to get out the nalgene and drink, a pita. Anyone have any sure fire ways to keep the tube from freezing? Tried blowing it out, insulators, but it usually ends up frozen when I need it most.
I think we need as much, or more water in colder weather. On our local ambulance rescue squad, we see as many, if not more, cases of dehydration during the cold months , mainly with older residents.

[randomscooter]

Is there anyone else out there that believes the seasons play less of a part than one's level of fitness in determining hydration requirements?

It seems to me that I don't need as much fluid when I am more fit regardless of the ambient temps.

Based on that theory, one may indeed risk dehydration more easily in the winter because they are not getting as much exercise on a regular basis and their level of fitness has declined?!

It seems like a plausible theory, especially considering that increased fitness level for many of us also implies a reduction in weight, accompanied by a reduction in overheating. But I think the fitness angle can be treated independently from the seasonal variation.

For a given fitness level there does seem to be a conventional wisdom that winter conditions are more demanding on hydration requirements. But I wonder if much of this is due to our tendency to overdress for the cold conditions. This initiates a cascading affect of creating too warm a microclimate, which causes overheating, which causes wetting out of the clothing, which causes chilling, so we hike faster to keep warm, compounding the problem, and on and on. I will admit that I've found myself in this situation very often in the past. I've recently been trying to short-circuit this cascade of events.

For me step one is to start the hike dressed very lightly. Usually I just wear a short-sleeved base layer, plus on colder days a long-sleeved lightweight base layer. If it's breezy I put on on lightweight windbreaker either with or in place of the long-sleeved base layer. Since the lightly dressed core causes my body to send more heat to my core I wear warm mittens to avoid cold hands. I need very little on my head other than possibly ear coverage.

Step two is to carry plenty of extra clothing, and use it. I carry two spare sets of base layers, at least two sets of spare mittens, two lightweight silk balaclavas, and three outer shells - a softshell, a hardshell, and the lightweight windbreaker. In addition to all this I carry an emergency set of inner layers that I almost never need to use.

A typical hike will illustrate. I start out with the base layers. If the breeze is light I run a bit cool, but with warm mittens and my ears covered I feel safe and comfortable even with my core running cool. Importantly, with my core running cool I don't sweat too much. If necessary I put on the windbreaker, but if this causes too much perspiration I will often remove the long-sleeved base layer to keep it dry. When I encounter a small amount of snow in the trees, I'll slow down a bit, taking the time to knock it down as I pass so it wouldn't soak into my base layers. Eventually though this slower pace causes me to get too cold, so I'll put on my hardshell in place of the windbreaker. I usually put the long-sleeved base layer back on since the hardshell against my skin is uncomfortable.

The biggest problem is that I sweat more due to the poor ventilation of the hardshell. I could use the softshell, but the snow that collects between my back and pack tends to melt in and dampen the shell from the outside. I believe getting wet from the outside is more serious than sweating (high energy consumption melting the snow), so when it seems impossible to avoid both I accept more sweating.

On many of my hikes I'll drop my pack for side trips. I'll make a decision based on the conditions. If it's a good day I'll keep on my damp clothing, because traveling without the pack gives it a chance to dry out. But I might change my mittens because my body will be sending heat to my core to dry out my clothing and my hands will likely get cold otherwise. If it's a harsh day or a long side trip I'll put on dry clothing in advance. Here's where the softshell comes into play. With no pack I don't have the wetting out problem, and the softshell will be comfortable even pushing through snow-covered trees. I'll often change between the various combinations of base layers and shells several times over the day.

Okay, this seems like a big hassle. So what's the benefit? I used to carry at least three liters of water, sometimes four, for a full day hike. Paying more attention to moisture management I now carry only 2 liters, and I often don't use it all. That's as much as 4 pounds less water, more than enough difference to compensate for the extra clothing. I carry a pint of hot apple cider. It's an extravagance that costs me about 1.5 pounds but is for me worth it. Interestingly, since I stay drier and more comfortable I'm more apt to actually drink and enjoy the cider rather than just carry it all day "in case of an emergency". I used to carry it all day and bring it back to the car still full. Kinda silly really.

Other benefits are that I feel much less concern (i.e., stress) about the risk of hypothermia caused by wetting out the clothing, I don't have to go fast just for the sake of staying warm (although I do still like to go fast just for the sake of going fast :D), and when I occasionally get the urge to just sit and enjoy the view I can do so comfortably.

[Neil]

I don't think that fitness levels have anything to do with heat output, sweating, or water loss. The chemical reactions that drive muscular (and all physiological) work are considerably less than 100% efficient. The energy lost is given off as heat. Fitness levels have a lot to do with the ability to do more and more of those chemical reactions per unit time and for longer and longer lengths of time. However, I don't think fitness affects the efficiency of those reactions.

Besides decreasing the work load being lean enables you to unload extra heat more quickly. Imagine wearing a fleece garment one centimeter thick and climbing a mountain. Some of us have even more than a 1 cm insulating layer. :eek:

[pete_hickey]

As far as loss of water, a lot is lost through the lungs. (related: Do dogs sweat?) Cold air is much more dry, and evaporates a lot from the lungs.

When I do the Canadian Ski Marathon (50 miles of XC-skiing in a day, with a full pack), I find that I drink a LOT. One of the reasons is that there are support people along the way with warm (not hot) drinks, which go down easily. If those people would not be there with their water, I'm certain that I would not drink as much.

IMO, convenience has a lot to do with it.

[ElectricMan]

I think you’re all right….:)

Pete’s point that you lose a lot of water through evaporative breathing is true. Also I believe not having water readily available (and it not being hot or warm) we tend not to think about it as much. I also think physical fitness plays a part in how much your body expends in water during physical exertion.

I met a guy last winter on the summit of Abraham, in Maine, that blew by me ascending the steep and icy summit cone. While we chatted on the summit he said he was finishing his winter round of NE115 and NEHH at the same time having already completing the 3 season round of each. :eek: I quizzed him on his small/ish pack and spartan hiking accoutrements. He mentioned he did not carry drinking fluids in winter. When I asked him how he could do that, he said “You work up to it”. This guy was definitely, doing the light and fast in winter thang.

I will carry 2 liters of hot tea for a winter hike and usually end up with a partial liter at the end of the day.

Inga, I’m interested, how much water do you typically carry for a winter hike?

[TFR]

When I asked him how he could do that, he said “You work up to it”. This guy was definitely, doing the light and fast in winter thang. It was discussed on VFTT a while back that you can not really work up to 'dehydration tolerance'.

[Inge]

[QUOTE=Neil;30538]I don't think that fitness levels have anything to do with heat output, sweating, or water loss. The chemical reactions that drive muscular (and all physiological) work are considerably less than 100% efficient. The energy lost is given off as heat. Fitness levels have a lot to do with the ability to do more and more of those chemical reactions per unit time and for longer and longer lengths of time. However, I don't think fitness affects the efficiency of those reactions.

Neil - I think you may wish to reread what you wrote.
Your fitness level is ALL about the efficiency that one is able to perform work.
As you become more physically fit it requires less effort and you become more efficient. If you are more efficient then you have less work lost as friction which produces heat. Heat is Sweat.
You are talking about Power. Just think of the "big" guy sweating it out to run a 100m dash. Then think of the "big" guy that has rippling muscles flying across the finish line at the World Championships. The work output is the same - work being force times distance. The input is obviously much different for these two fellows. Therefore the efficiency that they are preforming the same amount of work is Very Different. Lack of efficiency is measured in loss of work and this is the energy of the heat produced.

Electricman - I usually carry 2L of hot tea with lots of milk. In the summer I carry the same 2L of milk/tea but it is cool. This amount is for an 8hr trek.

I usually start and finish my hike by "running" or jogging. This is so that I get warmed up relatively quickly. I wear clothing that is easy to adjust to regulate my temperature - a thin layer,hat, vest, armwarmers (they go up/down or off w/o stopping), tights. Windstopper or windbreaker materials are used only if I stop or am getting cold. Gortex and the like do not breathe. Not breathing = sweating and I never want to sweat one bit. I find a thin layer over all is best. No double layers until all the other body parts have a thin layer.

More later -
Inge

[Neil]

Inge,
By efficiency I only meant the chemical reactions that result in muscle contractions. They are at best 25% efficient and cannot be improved upon. 75% is lost as heat. Of course being fit improves the efficiency of a running stride, say, but the chemical reactions responsible for extracting energy from foodstuffs and harnassing it for muscle contraction only capture a quarter of it.

But you are right, a fitter athlete will move more smoothly and convert a higher percentage of his or her muscle work toward whatever the goal is. Therefore less overall heat output per unit of distance travelled.

For plodding up a steep mountainside burdened with a pack though I often wonder just how much more efficiently I can move. Maybe if I got you to carry my pack for me?

[Neil]

If you carry ME!You weigh 90 lbs. Right? OK. I'll do it, but only if you carry all the water I'll need to drink. That'll lighten my load considerably, especially if you travel through sidereal time.

[Prino]

As far as loss of water, a lot is lost through the lungs. (related: Do dogs sweat?) Cold air is much more dry, and evaporates a lot from the lungs.

When I do the Canadian Ski Marathon (50 miles of XC-skiing in a day, with a full pack), I find that I drink a LOT. One of the reasons is that there are support people along the way with warm (not hot) drinks, which go down easily. If those people would not be there with their water, I'm certain that I would not drink as much.

IMO, convenience has a lot to do with it.

I don't think I would have been able to finish the CSM if those checkpoints with all those pints of fluid were not readily avaliable. Maybe I would ski a lot slower but then wouldn't make the cutoff.
Hiking in winter I pace myself a lot better.... something along the lines of Randomscooters post. With no one to help out with back up fluids it's critical not to overheat.

[AdkWalrus]

That'll lighten my load considerably, especially if you travel through sidereal time.

Dammit, I knew it would catch up to me eventually. Guess it's time for a leap year! Oh, not until 2008...? ;)

[Dory]

Mudhook,
I find the same thing, I just don't drink enough if I know I have to stop and spin open the nalgene to drink. Last season I chopped up an old fleece and made a carrying sack and sleeve for my hydration pack. I filled it up with hot water and wore it over my base layer, but under my outer layer, instead of in my daypack.
At first I ran the tube down my inner sleeve which worked well for non-freezing, but I found that when my hand bumped something, the water would trickle out and wet my glove. That sucked. Then I ran the tube over my shoulder and out at my neck. I was very concerned about the end freezing at first, but I just took a drink about every 5 minutes and it was all good to go. As a precaution, I do bring an empty Nalgene to pour my water into, just in case things do freeze up.
Dory

[LionRoar]

I strongly agree with Pete -- most people lose water through breathing than from sweating. Howard Glass, a local EMT from Keene Valley gave a lecture on hypothermia and said that the not drinking water exacerbates the condition, i.e. pale skin, slight imbalance, apathy, poorjudgement and/ or shivering.

My cardiologist was telling me that often we drink too much water; we're under the mistaken impression that drinking six or eight litres will replenish our water. But, after an outing see how often one passes urine. If one is going more frequently over the course of the night and the following day, then one consumed too much. That's your body regulating your water. One's urine shouldn't be clear - it should be light yellow.

In the warmer months I consume about two+ litres and my urinary output is minimal. In the winter, when our bodies fool us, I drink far more. As was mentioned above, it's far easier to drink warm water than it is to drink cold water. What one doesn't want to do in the winter, is to drink cold water. No matter how many layers you have on, no matter how hard one is hking, cold water chills the body making it harder for the body to warm itself. In winter I will take along the extra weight of a thermous.

LR