Yesterday, November 28, 2023, I almost collapsed on a windy downhill after eating a big meal and letting my body cool down while still really wet from riding hard the first 60 kilometers. It wasn’t even that cold out, probably 8C. But the temperature didn’t matter. I was lazy and had managed my body heat horribly and got hit with soggy, serious chills that I couldn’t shake (get it).
Like most people, I panicked at first. In fact, my training didn’t help. I recognized early hypothermia when I saw it. I could not get warm. There was nothing I could put on to make the intense shivers stop (which are apparently great for losing weight, btw). It’s a terrifying feeling being so out of control of your own body. Still it’s not as scary as when the chills stop and you get sleepy. That’s when you die. Apparently it’s a rather peaceful way to go once the shivers stop. But I didn’t want to die, yet. I have too much to see! It’s not unlike a video game, ‘cept there’s no respawn.
I pulled myself together and remembered my old training. I knew what to do. I’d just forgotten. “Push it, Rob!” I put my bike into a harder gear looking for the nearest slow-moving hill and dialed up my body heat grinding up a 4% grade out of the saddle. It worked. I was still soaked and cold, but my body got the message. It was like I had to remind it that we were not resting and digesting right now. The chills were my body complaining that it was too busy doing other stuff to put out the energy to heat me up. My body and I came to an agreement, first get warm.
After that the ride was largely peaceful. The full moon was beautiful. Downtown Davidson and the suburbs all lit up with Christmas stuff. It felt like my bought with death-by-chills was ages ago.
The whole last 30 kilometers home (mostly in traffic) I thought of all the things I had done wrong and all the what-ifs, all the newbie mistakes I had known better not to do, but did anyway. It was embarrassing, but fun, in a tortuous way, to re-learn it all again. What doesn’t kill you makes you stronger, right?
So here’s a quick reminder of the what I was reminded of, the standard things to do to stay warm and avoid hypothermia (and to not die if you get into real trouble):
The question I should have been asking was what needed to be removed to get my heat stable again. Had I bothered to check my layers in the restroom at the restaurant I would have seen they were completely drenched in the better part of the liter of sweat my body had release over the last 90 minutes (two liters if really pushing it). It didn’t feel like I was wet in the restaurant, but I was. Most of the moisture ended up being in the outer insulation layers I had on, which is why I wasn’t feeling it as much. The water vapor had made it all the way away from my body and been halted by my Gortex shell (which I’ll rip on in a minute). Ironically, had I removed that shell a lot earlier and added another insulation layer that breathed better I would have not been soaked and not known it. How do I know? Because just two days ago I did the same ride with nothing but my thermal base layer, a synthetic hiker shirt, and my absolutely wonderful Nano-Air Patagonia Hoody (by far my favorite piece of equipment in the whole kit). The Nano-Air had allowed all that moisture to escape completely, the Gortex had not. I should have removed all those wet layers at the restaurant. But I was lazy. I undid the layers to pee but I didn’t even check my layers. I won’t make that mistake again.
I also wasn’t wearing a thermal layer at all (idiot). It was too hot to wear one when I left at 1pm. By 5pm, omg, I definitely needed it. So I should have done whatever it takes to take off what I had on, and put on my warm, dry thermal layer before I went back out into the dark, windy, beautiful night with a full stomach hogging all the warming blood that my hands and feet and head could have really used instead. I’ve since decided to wear the thermal layer any time the temps are 15C or below. The wind from the ride will keep me from overheating if needed earlier in the day, and adding insulation and shell layers later will keep me adding things without having to make a big stop to completely undress and add the thermal layer.
In fact, having two thermal layers is worth the weight since the one I’m wearing will inevitably get wet and by the time I reach the tent I can change into the dry one and get cozy again. In a pinch, I can even change into the dry thermal layer on the road and attach the wet one to my outer bike rig to dry it out by the time I get to where I’m going for that day. Nothing like using a good downhill as nature’s own dryer (if it’s not raining, of course).
Sweat usually keeps us alive by cooling us off when we get too hot. There’s nothing like a cool breeze to evaporate that sweat on our bodies in the Summer, but the rest of the year? Nope. Rapid evaporation can drop your body temp to killer levels. This is why the first response to save someone’s life who has broken through the ice or fallen into a nearly freezing river of runoff in early Spring (which actually killed a river guide from the company I worked for during training a few years before me) is to get them dry even if it means stripping them in the middle of Winter and immediately getting them out of the wind and into a sleeping bag with another heat source, another naked body is best (and yes, that is the actual training I was taught). They’ll die if you don’t.
The body’s thermal system could be better. It doesn’t know that it is actually really cold outside, that there is no need for sweat. Wouldn’t it be cool if it did? The good news is that our brains actually do know this so we can signal our thermal system to do the right thing if we pay attention and take the time to do it. It’s almost never convenient to manage our thermal response to conditions and exertion but it’s always critical, literally a matter of life and death just as much as managing food, water, sleep, and traffic safety. Learning how to manage our thermal response is just the first step. We have to have the will to do it (which I didn’t yesterday).
“Well if water can kill you then I should be sure none of it gets in when it rains, right?” This is perhaps the most counter-intuitive truth of thermal management. Once it starts to really rain, not like a light shower, there is no way to exert yourself at all without ending up having water touching your skin. Either the rain is going to get through your layers and get to your skin, or your layers are going to be too impermeable to allow sweat to evaporate building up on your skin as if the outside water had made it in.
Another irony is that when sweat doesn’t evaporate the body thinks it needs more. So not only do you end up with hypothermia danger but you get dehydrated without even knowing it because it’s cold out (which also happened to me yesterday on my 90k test ride).
So what can we do?
Don’t get wet (when it’s cold). Seriously, I have no need to bike in the pouring rain at all. I’m not in some competition. I’m not after tough-guy points. I should just setup camp and get something done, or head indoors and meet some interesting people hiding from the rain as well. This also means only keeping an emergency rain shell layer like my Alpine Houdini in my kit. I’d rather invest the weight (and money) in a really good, light-weight tent rain shelter or Gortex shelled Mountain Hardware Bishop Pass sleeping bag.
Exert less. If I cannot stop. I can go slower. Turning down the amount of moisture (without turning off the metabolism powering up your personal heater) seems wise. Not everyone has that option, but when I do, I’m slowing down and sweating less every time.
Pack an emergency shell. The best anyone can hope for when conditions are really soggy is to keep that water close to the skin warmer than the rest. This means blocking the external wind completely from evaporating any moisture at all and rapidly cooling it down. This is why those working on ships wear well-sealed thick rubber rain suits (like I used to wear commuting in Winter in Portland, Oregon). No drafts at all get through those things. For me this is my light-weight Patagonia Alpine Houdini and a reflective LZLRUN Reflective Vest (which doubles for traffic protection if forced to bike after dark). (I ditched my expensive Patagonia Gortex shell. More on that later.)
Wear base layers that insulate even when wet. Professional river guides used to recommend that I get some long underwear that could keep me warm even when wet. It worked. You’ll see river guides always wearing long underwear under their trunks and life-jackets when the temperatures dip, even in Summer in Salmon, Idaho. They know that that base layer gets wet it will keep them warm anyway. This is the same reason cable-knit wool sweaters have been keeping Nordic fishermen warm for centuries even after they get wet. The wool and loft from the stitching (more on that later) keeps them warm and alive. By the way, down loses it’s insulation ability when it gets wet (more on that later) and cotton is the devil of personal thermal management.
Wearing a shell that blocks evaporation (instead of slowing it) is the single biggest mistake anyone can make with regard to regulating body temperature. This traps all that water vapor next to our skin and in our layers making it impossible to get dry. Usually, this is a bad thing (as I discussed earlier).
While bikepacking does require a shell more often than running, hiking, or backpacking because of the wind. Most bikepacking doesn’t need a shell at all, or at least not the shell most people think they need. A synthetic, long-sleeve hiking shirt is a shell depending on the conditions.
When some people hear “shell” they think “rain” but in reality protection from the wind is far more important in most cases since it is the wind+water combo that produces hypothermia. Protection from the wind is also far more important for cyclists that many other outdoor adventure sports.
There are all kinds of wind. Sometimes that is just a very light breeze in freezing temperatures that is just enough to blow away that warm layer of air held close to the skin by your hair or thermal base layer (which reminds me of thermal projection videos of people walking around, so cool). Protection from even these light breezes keeps moisture from evaporating too quickly (which is what gives that “bite” sensation) while still letting it evaporate and not build up. It’s the reason rolling down your hiking shirt sleeves down is usually enough on a chilly Summer night.
The solution is to wear the least amount of shell required, the most breathable.
If there is no wind and rain that means no shell at all. The base and insulation layer will cover it, sometimes just a base layer when pushing hard (think Nordic skiers and pro cyclists).
When there’s a bad wind adding another insulation layer might be the answer instead of a shell, depending on the material. Compare the Nano-Air to the well-known Nano-Puff Patagonia stuff, for example. I overheat in the Nano-Puff stuff compared to the Nano-Air because it almost doesn’t breath at all. Both are synthetic, but the Nano-Air let’s more air escape, which is usually ideal. Sometimes, however, the Nano-Air is just a bit too cold when the wind is really blowing. This is when the Nano-Puff stuff really wins. But, what doesn’t work, as I’ve learned through sad experience is adding any shell to either of them. This causes them to immediately soak in sweat with any exertion at all. In fact, when it’s really windy, or the wind is colder than usual, I’ve had far more success combining the two, Nano-Puff over Nano-Air, or even two Nano-Air layers, a hoody and a vest. But never a shell unless it is raining and there is no alternative. I plan to test a third non-shell insulating layer, a down hoody to go with this. In fact, my down hoody will likely replace my Nano-Puff jacket in my kit. Down is amazing because it works in so many different ways. All Tour Divide competitors swear by it. Most use it as their only insulation layer.
Finally, I do pack an emergency Alpine Houdini shell and wear it during particularly windy conditions as a temporary measure making sure to regularly take it off so everything can air out. Its also there when and if I need to completely shift into “soggy” mode because I’ve been caught in a cold rain storm and cannot escape.
Gortex™ was made mostly for people doing things in Winter, snowy weather, which also happens to usually be very low humidity levels. This is what creates that amazing desert mountain powder I used to ski on in Utah. Water doesn’t have a chance to become humidity at those temperatures. It freezes and falls to the ground, which is absolute bliss for skiing and for anyone wearing Gortex and an insulation layer designed for sports like Nano-Air™ from Patagonia. It is just permeable enough for a minimal amount of water vapor to get out, while keeping external water out completely. This is great for all these people but Gortex is just not worth the weight, bulk, and expense for just about everyone else, including anyone bikepacking across most of America all year round.
Gortex is really heavy compared to any impermeable synthetic. My Patagonia Storm shell is 477 grams compared to my Patagonia Alpine Houdini at 182 grams. That’s not nothing.
Gortex doesn’t pack down like other synthetics. People who use Gortex are usually wearing it all the time, because it is really bulky. My Houdini takes up less then one-third the size of my Gortex shell and packs down into its own stuff sack. Gortex can actually be damaged by packing it down too much.
My Gortex jacket suffers from another problem. It has too many ventilation options. All the zipper armpits and vents actually let bone-chilling tiny draft in when I have to switch to “soggy” torrential rain mode. I don’t get these with the water-proof Houdini. And because Gortex “breaths” it also allows a fair amount of air in to make contact with my soggy layers cooling them down. In short, it’s expensive and it sucks. In fact, I’m now convinced Gortex has no place in cycling kit at all at this point—especially in a light-weight bikepacking kit. I’ve really completely changed my opinion on this one, perhaps extreme winter fat-bike conditions, but I’ll never be doing that.
One seriously beginner mistake I made because I was in a hurry yesterday was just wearing what I had on and adding more layers onto it. This is another counter-intuitive thing. More layers means more warmth, right? Wrong! (That always reminds me of that scene from The Christmas Story.)
More layers—especially under exertion—means water molecules have more layers to traverse and are more likely to condense on one of those layers on the way instead. As those layers get wet they allow even less water vapor through ultimately clogging up the whole thermal regulation system. And when down or cotton gets wet, it stops insulating completely.
The solution is to force myself to stick with no more than three layers. By picking the best layer for the conditions, and also forcing myself to change my layers as needed for changing conditions, I have the best chance of staying not just alive but cozy and happy. After all, the great fun of the “play outdoors” game is getting everything just right to be cozy and happy. That always feels like such a great win.
The base Meriwool “heavy” thermals go on at 15C or below, no matter what. That just makes everything else easier to manage after that. 15C is about the point where wind chill while riding it going to make thermals comfortable even if slightly overkill. But I don’t have to wear much of anything else on top of them.
When it gets cold the first shell to add on top of my thermals is my synthentic long-sleeved hiker shirt. This blocks the wind while allowing it through enough to evaporate the thermal layer. I always consider the shirt an outer shell layer and never under any other layers because of its lack of breathability. (The shirt’s real moment to shine is when cycling in warm to cool weather conditions.)
As it gets colder, I swap the synthetic hiker shirt for a Patagonia Nano-Air layer, either the vest or the hoodie, usually the vest first, then the hoodie later. While the vest might be my most fashionable piece of kit, the dorky hoody is my favorite piece of cold weather kit. I can put the hood over my helmet easily, even adjust how much air gets into my helmet vents, or zip it all the way up so just my face is sticking out, all while still wearing a helmet. Regulating the pocket of warm air between my head and the outer breathable Nano-Air hoody while wearing a cycling helmet is just amazing. I cannot overstate how effective, efficient, and easy it is to adapt to the vast majority of variations in temperature and exertion while bikepacking.
When it gets colder I have a few more options. I can wear the vest on top of the hoody. To counter the wind on my core. Then later maybe I swap that outer vest for my Mountain Gear Ghost Whisper/2 down hoody. Even though that means wearing two hoodies. The Mountain Gear hoody is really small and doesn’t fit over helmet (but good when off the bike). If the wind was still a problem I could even put the down hoody over the Nano-Air vest/hoody combo, which is still better than adding a non-breathable shell over any of it unless conditions are really extreme.
By the way, very rarely will my waterproof “shell” layer be needed at all. It’s mostly just an emergency rain shell. For now it’s my ultralight Alpine Houdini. For the Tour Divide I might swap it for a Patagonia Storm10 which (for 100 grams) gives way more wind and rain protection and has a hood that will fit over my helmet (unlike my current Patagonia Gortex shell, which is great, but designed more for snowboarders and the like, and my snowboarding days, sadly, are over). But most of the time my outer layer will not be waterproof at all, perhaps not even particularly windproof, just adding the additional third layer of insulation is the only wind “shell” I need—especially with the Whisperer’s outer wind-resistant but permeable rip-stop outer fabric. God I love that thing.
That last section was all about changing things up all the time. It’s worth mentioning in a section all to itself, how important being able to adjust layers quickly for anyone as active as I want to be on my faster-than-touring-pace bikepacking adventures.
To stay flexible I considered putting my main layers in a waste pack. But that turned out to be a horrible idea. As much as I loved my waste pack back in Moab, Utah and Salmon, Idaho when guiding river and mountain adventures there, having a waste pack while pushing hard on the bike messes with the thermal dynamics of my layers. But it’s not the only thing.
When I used to wear my livestreaming rig it would completely mess up both my balance and thermal and even my back musculature. If I wanted to destroy my body—especially my back—I would take up backpacking instead. I always had a completely sweaty back and strip down my front and my bag eventually became so soaked with sweat it wasn’t wearable because it smelled so bad.
“But what about all the people wearing waste packs, hydration packs on Tour Divide?” Everyone has their own priorities and they vary per event. For example, you never see Lael Wilcox putting anything on her body when she breaks records, presumably because she likes the feeling of body freedom and knowing her thermal dynamic system is going to work—especially since she wears a down layer on occasion that a hydration pack would completely negate.
In fact, people don’t think of this stuff when they first go for these setups, and most will never be affected by them since they don’t put enough time into their systems to see the flaws. But I have experienced enough to have preferences, and some of them surprised me. On all the mountain bike tours I did and guided in Moab, Utah not once would I have considered, not wearing my waste pack with water bottles in it. But those always happened in the Summer months. Now that I have a lot more experience putting in long hours during the other months I see how a waste pack doesn’t play nice with those kits. I would never have known this without putting the time in during those seasons. And if there is one thing watching Tour Divide videos has taught me, it’s that people riding TD never prepare properly for cold weather and are regularly surprised by it. It’s actually just a bit comical (and validating) watching a pro cyclist realized they have zero cold-weather survival skills. It also makes me feel even more dumb not taking the time to do cold weather the right way yesterday on my nearly hypothermic ride in 8C weather (sigh). Yesterday, as I peeled off the soaking wet layers the section under my belt in front, and on my back where the waste pack was was the most drenched of all. These are areas that adjusting the zipper on my jacket would have had a hard time unlocking as well, so why complicate it further by crushing those layer sections against my body, not any more. I’m sending the waste pack back. I admit I did like that it covered that problematic seem between pants and top nicely, but just not worth it.
Related to the waste pack discovery, I’ve realized that tying off jackets and layers around my waste can cause the same problem but to a lesser degree. Plus you have all that stuff flapping around in the wind, making annoying sounds banging into the frame the rig, or worse, getting caught in the spokes. I’m looking forward to finishing up my cockpit design with stem stuff sacks webbing so I can stow that stuff easily with a small stop.
The tighter the layer, the less likely it is to keep you warm. This is the entire idea behind down. It traps a layer of warmth next to the duck between it’s waterproof feathers and body. We steal it to make our own layers.
Do an experiment to prove this. Compare a tight cycling arm-warmer to just rolling the sleeves down on any good synthetic, long-sleeved hiking shirt. The shirt isn’t as “aero” but it is much better as regulating arm temperature because it allows a pocket of air to form that the tight arm-warmer does not. The shirt also allows the heat from the arm pits to travel through the sleeve contributing to the warm area surrounding the arm better.
You can do another experiment with tight fitting wool/alpaca socks and loose fitting ones. I’ve found combining the two works nicely.
Perhaps the best proof of why puffy loft wins is those doing bike tours in temperatures several degrees below 0C. They have monstrous covers over their handlebar grips.
Ever notice that a hoodie is much warmer and cozier than a jacket and hat? There’s a very real scientific reason for it. Here’s an experiment. Sleep out with your head exposed from your sleeping bag. One night wear a tight fitting beanie (like most do). Another night, wear a comfortable hoodie instead. I promise you will notice the difference, not only in heat, but comfort. Even loosely fitting beanies always give me headaches.
With a hoodie the substantial amount of heat coming from the arm pits and the core is able to float up behind the neck and around the head.
The hood is usually not tight so that allows a wonderful pocket of warm air all around our head and ears. This just isn’t possible with a jacket and hat. In fact, gaters and scarfs are popular—especially gaters these days—because they restore this heat pathway from core to head and look more fashionable (to some) than just wearing a technical hoodie. But all the pros know this and don’t mind the look of a hoodie. This is why parkas that cover the entire core, down past the hips, and have a hood with a big section past the face are so warm. All that warm air is constantly flowing exactly where you want it unimpeded.
This is also the reason that my baggy flannel onesie is still my favorite thing to sleep in, even more than my marino wool thermal base layer. It’s just less practical when it comes to going to the bathroom at night, or getting ready for the day quickly the next day. For that the thermal base layer I’ll be wearing on the bike always seems most efficient. I just get up, warm up a beverage, pull on my shorts and other layers, pack and go. I’d sleep every night in my flannel onesie otherwise.
I used to hear this all the time from veteran skiers in Utah. You’d think there was absolutely no way to have cold feet wearing those big insulated ski boots. But if you have ever skied, you know you absolutely can—especially sitting on the lift in the wind going up the mountain. So what is going on?
The head and neck are our greatest thermal regulating tools. When they get cold the body reacts by pulling in all the blood from our extremities to protect our more important core organs and brain. This, unfortunately, means that the hands and feet are “expendable” according to our body. This is why frost-bite almost always affects them first. You might not get frost-bite just because you didn’t protect your head and neck, but you will get cold hands and feet. Your body clamps down these capillaries preventing them from even getting that warm blood, pretty harsh, I know, but you can assuage your panicked body by heating your neck and head.
I used to use this fact to my fashionable advantage. When I was in the greatest shape of my life and didn’t like putting all those layers on hiding it [“OMG, this dude is so vain!”] I would wear a beanie and a scarf with my favorite t-shirts all winter long here in North Carolina. In fact, sometimes I wouldn’t even wear a shirt in the chilly apartment. Just a beanie. It worked great, perhaps even helped me get Doris (my wife) to like me, but who knows. The point is, regulating your heat through your heat and neck is perhaps the most effective personal thermostat we have available to us.
I’ve noticed that mistakes with thermal management don’t affect me as much when dealing with my lower body. In fact, I regularly wear just shorts with wool/alpaca socks and some warmer core/top layers. I don’t know why, but the body seems to permit that more. This also means that I can get away with wearing a shell on my legs without the accumulating moisture blowing me up more than my torso. Still, starting with the right base layer is probably best no matter what. Plus, the feeling of a soft base layer against the skin makes those cold, synthetic materials feel better. It’s one of the reasons I love my Nano-Air stuff so much. It just feels like you are getting a big hug all the time.
I recently read a reminder to always care an additional, identical base layer—especially if exerting yourself. This provides the options of swapping it out and drying the other one out and continuing that process infinitely. You cannot do that with only a single layer. Drying out the base layer is the quickest way to rejuvenate a spent thermal system after hours of riding. This is why putting on dry socks before going to bed has been a Boy Scouting tip people have been giving out for decades.
When the debilitating chills hit me yesterday my first thought was “find shelter” and couldn’t think of anything. I’ll be more vigilant about my options going out next time. I think having a sort of escape plan in the event things get really cold, really fast is a thing to be constantly thinking about so that it becomes second nature. Now that I’m warm and writing this I realize the best, universal self-rescue plan in such a case would have been to immediately find a hill to exert myself on to turn up my body heat even if still cold, then finding shelter from the wind, pitching my tent shelter, unpacking my layers, getting naked and putting on a dry thermal layer, socks, and down layers, possibly even hopping into my down bag for a bit. That’s a skill I want to practice in the coming weeks by forcing conditions where I get cold and need to warm up quickly. That’s the sort of thing that if you are out remotely away from people and get it wrong, you die.
I always love warming my hands with my camp stove while making a beverage in the morning or noodle or something at night. It might not be a full camp fire, but it’s just enough to make things cozy. Few things warm me up faster than hot bouillon broth, noodles, another beverage depending on the mood. The thing about broth is that it doesn’t sap blood away from extremities because there’s nothing to digest, so you get all the warm benefit of soup without the energy sapping digestion, which might be fine at other times.
I’m not sure if drinking bouillon confuses my body into thinking there’s something to digest and therefore robbing my hands and feet of warming blood, but it might. I just haven’t experienced it yet. What does confuse my body is having a big meal and then jumping immediately back on the bike. “Woah, are we exercising or refueling here? What’s going on!?” That’s why I got the chills after eating that big meal. My body was really confused. As soon as I hit that hill hard it got the message and shifted back to metabolising and warming everything up. But I wish I hadn’t confused it in the first place. I think the solution is to save the big meals to times when I know I’m not going to be moving again for at least an hour. Then some of the meal can get digested and top up my body’s batteries without forcing it to work harder than it should doing that and exercising. Everyone who has done competitive endurance sports knows you just can’t mix the two if you are pushing hard. Your body will literally eject the food refusing to digest it if you make the choice to go hard after eating a big meal. But going long and slow it seems to be okay, for me. In my case, there was the other job of warming my body that I made it do that it did not like. “I cannot keep you warm and digest. Sorry, you’ll have to pick one.”
There’s a lot to think about, even for someone who knows what to do and how to prepare. That means there are many variables. I suppose that is what makes all this so challenging and fun. Get one thing wrong and you could literally die, yes, even on a lame-ass suburban trail. The risks go up as we age as well. Just adds to the fun.
It goes without saying that all of this required monitoring and planning, being aware of the current temperature and subtle queues that your body is not happy before it goes too far. It’s easy to put the headphones on or focus on something else and forget to pay attention to those queues from the body. I was getting them all night, a little too chilly on my calves one moment, the clammy feeling of my torso instead of a cozy feeling, even the tightness of my shorts around my waste after that meal. All signs to adapt in ways I chose not to. Well, I will next time.