Self-diagnosis of hypothermia onset

Question

Does anyone have experience with self-assessment of early stages of hypothermia, in the context of the other subjective experiences that may come with solo wilderness adventures? In my experience, hunger, thirst, fatigue, sleep deprivation, endorphins, adrenaline, feelings of elation/euphoria in the presence of wild nature can obscure the described symptoms, and thus cloud the decision to rally to reach the planned stopping point, or make camp immediately and warm up.

Are there distinct telltale signs that occur before impaired judgment becomes a significant factor?

Thank you everyone for posting general hypothermia diagnosis / treatment notes such as https://www.mayoclinic.org/diseases-conditions/hypothermia/symptoms-causes/syc-20352682 and specifically regarding use of a thermometer (consensus: don’t use a thermometer to diagnose hypothermia in the backcountry) https://outdoors.stackexchange.com/a/19899/15978

Answer 1

I've been in the early stages of hypothermia before, and I can tell you from experience that when you're in the early stages of hypothermia, you're convinced you're okay and that nothing is wrong; as in shivering and shaking uncontrollably while trying to convince the people around you, "Oh I'm fine, I don't feel cold at all I don't know why I'm shaking so much..."

Your judgement is one of the first things to go when you're hypothermic, having been through it I can say it's a real eye opener, and a humbling experience, because after the fact it's obvious to you that you were experiencing the textbook symptoms, but in the moment you were oblivious. Once you get into the beginning stages of hypothermia, your chances of self-diagnosing its onset are slim, and it would be foolish to be arrogant enough to suppose you could have the capacity to recognize when you were hypothermic.

The fight against hypothermia begins with prevention. When I'm out in the wilderness, I'm very aware of what conditions can lead to the onset of hypothermia, and work to prevent it before it ever has a chance to set in.

The key ingredients for hypothermia are wet and wind, doesn't matter how warm it is outside. If you ever find yourself exposed in the wilderness while wet and you feel yourself starting to get cold, then you need to take care of yourself immediately, especially if you're solo.

You must be conscious about regulating body heat while you're in the wilderness, and you do this mostly by layering your clothes, and wearing layers that do not hold moisture (see Does cotton really kill?). Keep your body warm, but never so warm as to make yourself sweat and get your clothes wet. If you end up wet for some reason like falling into a creek or getting caught in an unexpected rain storm and feel yourself starting to chill, then your priority immediately becomes an effort to get warm.

Movement is often enough to keep your core temperature up, but if you're soaked to the bone, or exposed to the wind and you're losing heat faster than you can generate it, then you need to stop and do something about it. If wet, get out of the wind, take off your wet clothes and wring out as much water as possible. You want to let them dry as much as you can while you're not wearing them. You'll find it easier to stay warm wearing less and being dry than you will wearing wet clothes, even if the only dry thing you have is your skin. Do jumping jacks, run on the spot, do push ups, etc. Anything that will get your heart rate up. You may even consider starting a fire to help dry your clothes and keep yourself warm while they dry. You're level of exposure and distance to a warm place are factors in determining your level of risk and need for a fire.

If you have a good breathable wind/waterproof jacket like Gore-Tex, then you can get away with continuing on while your mid-layers are still damp, so long as you can stay warm enough without shivering. As long as you keep moving and generating heat, your body heat will actually be enough to slowly dry your clothes inside you jacket, at the very least it should be enough to keep you warm while you keep moving and get yourself to a warm place where you can properly dry out.

Bottom line is if you're debating in your head whether you should stop and get warm, or keep moving and risk getting colder, then you should probably stop sooner than later while you still have to mental capacity to make life-saving decisions.

Answer 2

Mental changes are generally hard to detect and have other common sources like blood sugar, hydration, altitude and strenuous exertion, but these are what I use to track my mental state when I'm by myself:

A change in how much I care about discomfort

If I find myself thinking "This icy wind isn't really that bad after all" I'm probably wrong. If some clothing goes from feeling damp to feeling clammy it isn't just in my head. Thinking "Don't be silly it's 50 degrees out just because there is a little wind doesn't make it cold" is silly.

Being grumpy

If my mood deteriorates rapidly with no obvious cause I try to consider an environmental cause if I notice.

Being less adept

Similarly if adjusting gear that normally is effortless takes a couple tries or two hands when it normally takes one is a sign.

I often play with something in my hand and store it in an not conveniently accessible spot in my pack. If I start to drop or fumble it putting it away correctly involves looking things that would probably make me feel better, like extra clothing, snacks or water. Of course if I'm even sorta off putting it away properly probably feels like too much hassle.

Being less clever

I often keep a little walking hum going and when it seems like too much of a bother to come up with the next line I take a second to consider if something is bothering me.

Similarly if my thinking narrows to a simple loop "just keep swimming" or the like it is past time to consider making a change, and it may take a long time before that thought inserts itself.

Being uncertain or worrying

If with no new facts the plan I set out on seems more daunting or precarious than what I planned for I take it as a sign I'm off peek and I ought to take a sheltered break as soon as practical to re-evaluate.

Answer 3

Disclaimer: Despite a comment I made earlier about how I too would like to hear about ways to test for hypothermia, I should stress that relying on this could be potentially dangerous and should be a last line of defense, not first. That is, always assume that you could be even if your test is negative, instead of assuming that you are not until it is positive.

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TL;DR

1) Bring a watch, and estimate ahead of time how long certain activities should take. Time yourself doing them, and if it takes too long just assume you are compromised.

2) Bring a radio, and periodically (often) check in, preferably with the same person each time. Let them know ahead of time that they must tell you if they feel like you are reacting slower, or if you seem confused or otherwise weird. Cell phones can work if you are guaranteed good coverage.

Long version

I once noticed, because of a nearby clock, that it was taking way longer to do things than it should have. It was taking 10-20 minutes to do something that should have taken 1-2 minutes. I immediately abandoned what I was doing and tried to remedy the situation that was causing my decline. I might not have noticed if it weren't for my time keeping.

That said, the above situation was not hypothermia, but it was a different situation that can have a few similar symptoms, such as confusion, slowness and loss of time. Still, it makes me wonder if a watch could be a useful tool (again, last-line defense) for noticing some mental effects of hypothermia. Estimate ahead of time how long it should take to do certain activities, and time yourself. If it takes you 10 minutes to get out your pot and fill it with snow or water when it should not have, then immediately abandon your quest and seek help.

So the advise: Use a watch and keep track of the timing for your activities.

Since the above was not hypothermia, I was not going to post it as an answer. But I just realized I have another anecdote that is more closely related to hypothermia...

This next one is a negative, a warning that you might not detect it, rather than a positive.

I have recently started driving with my windows down and my arm outside the window while it rains. I have realized it's actually kind of nice to feel the wind and the rain. The rain stings at high speed when driving on the highway, but all along the rainy drive, it felt good, even invigorating, and I did not suspect any problems.

However, the last two times I did this, I did not notice until after, once I was done with the drive and sitting in a building trying to do other activities, that my arm and hand that was exposed to the wind and rain was not performing as well. When manipulating something with both hands, the one was not doing as well as the other. Or when trying to open a jar or bottle, I could not get the cap off using that hand unless the cap was already loose. When I touched the bad arm/hand with my good one, it felt cold to the touch of the good hand even though it felt fine by itself.

My situation was not dire, but it was still concerning.

Let's transfer this over to a case that is exactly in line with your question...

Instead of just the one arm exposed to rain and high winds, still having a good arm to test it against, what if I were instead standing out in a hurricane or blizzard such that my entire body was subjected to this? My entire body could get cold and not work well without me even noticing, just like my arm, but I would not have a known good part for comparison if I was by myself.

That is scary. Be warned, and be careful.

Back to the time keeping I mentioned above, I have read about high altitude mountaineers bringing lists of simple math problems and timing how long it takes them to solve the list of problems. In fact, I recently read about a few guys who decided not to do a climb they were about to do, because it took them twice as long as it normally took them to do a bunch of simple subtractions.

Your best bet is going to be not going solo. But if you insist on being solo and still want some of the benefits of having someone to help judge you, perhaps you could bring a radio and periodically talk to someone, preferably the same people each time you check in, and they can tell you if you sound weird, slow, or confused. Make sure they understand their job before you even start your journey and check-ins.

The radio idea also has the benefit that you can keep in touch with people and it can provide a morale boost. Obviously, if the area has excellent cell phone coverage then a phone call can serve the same purpose.

Answer 4

It's reasonable to identify stages up to the start of shivering. But shortly after that judgement goes out the window.

If you are traveling in a group, set up a buddy system. Each person has a buddy and you monitor the other party for symptoms.

Look for the 'umbles.

Fumbles -- fine motor coordination. Trouble with zippers. This can also be caused by numb fingers and cold forearms.

Mumbles -- mumbled speech. Can also be caused by cold cheeks, but listen to the content. Listen for disconnected statements, non-logical thinking.

Stumbles -- loss of major motor coordination. You've got troubles here.

Note: Low blood sugar can cause similar symptoms. Fortunately the cure is the same. Feed the victim sugar, hot sweet liquids and warm them up.

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Anything gets better with practice. When I worked at a school with an strong outdoor program EVERYONE -- staff and students alike -- took or ran two classes in hypothermia per year. The fall one was on cold weather hypothermia, the spring one on cold water hypothermia. Each talked about the nature of the hazard, symptoms to look for, and what to do about it. The lessons were about an hour, followed by a test that kids had to score 80% or better on.

Senior boys and staff had a stiffer course, with more emphasis on spotting symptoms in other people, and gaming out scenarios. (It's really easy to start with a single case of hypothermia, stop to deal with it, and now you have half your group showing symptoms.)

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All emergencies are easier (but not easy) to deal with if you prepare, plan, and practice. If you have memorized the initial responses, they can carry you through while you finish panicking.

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Practices:

Go outside on a sub freezing day dressed in running shorts and a t-shirt. Dump a bucket of water over your head. Have a set of tasks to do while you are cold.

• Go through a knot ladder (two poles set 3 feet apart where you have to undo a knot or hitch in front of you then re-do it behind you. Common in scout camps)

• Pound a few nails into a board.

• create shavings for making a fire.

• Drive a screw into a board.

• do up the zipper on a garment you aren't wearing.

If this is easy, then you aren't cold enough.

Yes this is dangerous. You should have a monitor per 'victim'. You should have access to a warm space, with food and hot beverages after.

The activity should be one that requires the person to stand and walk around. After drop (cold blood from limbs hitting the core resuming use of chilled muscles) can be serious. When treating serious hypothermia, you try to warm up the core while keeping the limbs cool, so you can get a head start on the afterdrop. This is for cases where the victim has lost consciousness.

On canoe trips I have been out on rainy blustery days. I felt fine, but all the work was being done by my trunk muscles. I was borderline chilly -- goose bumps. Started to rain, and I was starting to shiver lightly. We hit the shore, and started gathering wood to build a fire. I stumbled out of my canoe on cold legs. Two minutes later I was shivering violently -- so much so that I couldn't control my hands enough to light a match. The shivering fit passed in a few minutes, as further moving around got me warmed up. Since then I've kept a kit in my PFD pocket that has a chunk of fire starter several wooden matches and a striking surface wrapped up in a square of aluminum foil. I can get a fire going in 1 minute after hitting the shore. Even shivering I have enough motor control to break branches off of the bottom of spruce trees to add to the fire.

Answer 5

One simple check that I have used is to touch your thumb to your other fingers. If you can no longer touch your thumb to your pinkie finger (which usually is utterly trivial when warm) and if it is difficult or you can't do it at all, you should definitely think about warming up. I have gotten cold to the point that I couldn't, but it was at a base camp with a cabin+fire that I could use, so it didn't get serious.

The rationale is that when you get cold, you start losing dexterity of your fingers, and touching your pinkie finger and thumb is a pretty good barometer. The other answer is far more comprehensive, but this is an easy test that I do when out in the cold as a first check that takes no real effort. You usually lose finger dexterity before some of the more serious symptoms set in (or in my experience that it what happens to me). This site mentions this test and some of the more classic signs as well.