Rode 186 km (115 mi), beginning hypothermia at the end? Is their clothing that truly protects against -1/-2 celsius at night?

So, last Saturday I did another century+ (115 miles; 186 km). First of all, again, I am amazed how well TrainerRoad prepared me for this, having done sweet spot base training and sustained power build intermittently. Whatever I felt, whenever I felt it, I managed to push through.

Anyway, I started at 9:40 in the morning and it was 3 deg celsius outside with light rain. I was wearing Craft Active Extreme as a base layer, Assos Mille GT Fall (5-15 deg rated), and I had an AGU rain coat. Was wearing the Assos bonka big tights (really warm!), thermo, wind sealed and waterproof over shoes and gloves by Grip Grab, and a neck warmer and a cap. So basically, I thought I was prepared for the worst.

Immediately, I noticed that I had to eat more (I guess due to the cold weather my body wanted more), even though I was still riding in zone 2/3 as I did in other centuries. At 16:15 the sun started to go down. I put my lights on, I was in a happy place: “I am prepared for the cold”. So I thought…

At 16:15 (finished at 17:30… I was slow but I had to self-support so I had a lot of kit on my bike unfortunately… 25km/h only)… I noticed that there was a bit freezing to the ground, I looked at the temperature and it was 0 to -1 celsius. At around 16:45 I started shivering a bit. I thought: is this the beginning of hypothermia? But I also thought: only about 10-15km to go so I should be able to do this. And then (and then you know you are exhausted) at what I thought were the last 3 km it turned out to be 6km and I was negotiating every 100 meters with myself whether I would be able to make it, only to give it the final push through the last 2 km with 30-35 km/h average.

So what I wonder is… should I be proud that I finished? Or was it actually really stupid and should I have stopped before?

Also… is there clothing (regardless of price) that allows you to ride at freezing temperature at night? For instance, Assos sells thermal base layer + mid layer + jacket in the ultraz series (mille gt as well as equippe rs). Would that truly do the trick? On the assumption that you keep drinking and eating of course. For me, it felt freezing cold. But of course some of you are also riding in way extremer temperatures than I have done.

What should / could I have done differently to protect myself against impending cold weather conditions?

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Other than a vented Helmet Did you wear anything on your head?

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Yeah, I wore a fleece cap. My head and neck felt fully warm (and I have a beard for that reason). Personally, it felt the problem lied in my torso area. But it may also have been simply that my whole body was too cold.

Edit: I had the neck warmer of merino wool covering my whole neck, and the cap over my ears and forehead. And I wear glasses. So most of my face was covered. And it was only wind force 2, so not too much wind either at that moment. Or… my face was numb and I simply didn’t feel it.

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Some form of down helps, maybe add some kit that uses primaloft gold.

I strap an endura primaloft gilet to my bike for emergencies or long stops. Could certainly help if it was your torso that was getting cold.

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How do you strap it to your bike? As in literally: where do you carry it? I already have my rain coat in one of my pockets.

Sounds like you’ve got the top sorted about the best you can.

My best/ warmest winter base layer is actually the thinnest; it has a wind proof panel which makes the torso warm.

I take it you had good socks and overshoes too.

Merino stuff is great to for keeping you dry and warm if you haven’t got any.

Winter bike has a pannier rack and use a single voile strap but I think you could get extra clothing under the top tube with voile straps too. For winter, a small frame or bar bag could be a good idea too.

Sounds like a pretty epic ride!!

Cold is one thing, but the combination of temps <5C, rain and wind (or air flow from cycling) can quickly become lethal if you are not prepared.

Although it does sound like you were reasonably prepared. Rain jacket is good, neck warmer, overshoes, etc can all remove some of the misery of cold wet rides. And digestion actually provides warmth from the inside, so continuing to eat was a positive too. Solid food is probably better from this perspective, but the quick hit from gels or chocolate can be good for morale too.

One thing you have to accept is that no matter how pricey the rain jacket, or how “waterproof” the overshoes, if you are out riding in the rain long enough, it will get in - whether running down the neck or front of the shins, or leaking through the seams, etc.

So then it comes down to choice of fabrics, and keeping the wind off wet skin.

I am a huge believer in merino wool base layers, as they retain a reasonable degree of insultation when wet. Many other fabrics fail miserably on this score. And I am going to strongly disagree with the suggestion of down elsewhere in this thread - down is awesome when cold and dry, but loses nearly all loft and insulation when wet. I also tend to double up on base layers in the conditions you describe - a lightweight T shirt style baselayer to keep the shoulders warm (rather than sleeveless) and a LS base layer over the top of that.

But the real killer in cold wet conditions is the loss of heat from wet skin. You NEED to keep the wind off wet skin. Cold hands and feet are miserable but not dangerous provided your core stays warm. So for me, a windproof gilet is essential (and very versatile). It doesn’t need much insulation, and has no sleeves, so it packs down very small, but ensures your torso stays warm. Given many good quality technical rainjackets come in black only, my gilet is bright with reflective detailing.

And when conditions are worse than expected, be prepared to embrace unconventional solutions. One Fondo I did handed out trash bags at the top of a long wet alpine descent. Tear holes for the neck and arms, worn under the jersey but over the base layers. Zero style points, but surprisingly effective. If unsupported, stop at a cafe or gas station and ask for a trash bag - buy some food and tip them a dollar/euro/whatever for accomodating your unusual request. I have also heard of people putting plastic bags on their feet.

Finally, in terms of on-bike storage for extra clothing, either a half-frame bag, or a seatpack. These remain relatively aero, and are quick to fit and remove.

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I think your choice of clothing was probably spot on. I think you probably were just very low on energy due to the cold despite eating more. Despite having done other centuries was this the first one you’d done in very cold weather and were you actually out on the bike longer? Every long ride I’ve been on always seems to be 30/45 minutes too long irrespective of the actual length of it.

I’ve got one of these: Castelli Alpha ROS Cycling Jacket

it’s normally too hot if anything. It’s an amazing bit of kit.

Carry a thermal blanket. They work a treat for extra insulation if things get serious.

I don’t do cold weather. I can’t comment on riding in cold conditions.
However, I’ve spent plenty of time on the water. You need to keep that compost heap warm with lots of food. If it gets cool, something as simple as a cup of noodles can fire it back up again. (That’s if you have access to a servo along the way).

Can’t imagine a jacket rate 0 degrees to -5 would hurt.

I also think there’s an element of the more you do it, the more ‘comfortable’ you are in the cold. A lot of early riding in the UK now means that anything around the 0 degree mark is fine.

I’ve ridden/raced on fat bikes down to -16C but in general it’s the temperatures around freezing that are the worst as things aren’t dry enough so any precipitation or ground water is still a liquid. The Canadian Mounties did experiments to find out the worst conditions for hypothermia, turned out to be rain at 4C.

From your description you were just cold, it’s unlikely you’d have the motor coordination to continue riding your bike if you were hypothermic, even mild symptoms have an impact on motor function and behaviour. I’ve approached mild hypothermia just once in fifty years in the mountains, it took nearly eight hours to warm back up and feel right.

Temperature management is key, you want to be in the Goldilocks zone, not too cold, not too hot. Did you overheat at any point and get your base layers wet? Once that happens you’ll chill pretty quickly. Things like pushing too hard on a hill so you sweat is common - partially unzip your top layers at the bottom of a hill (take neck buff off if you have one), at the top zip back up and put the buff back on. Of course if it’s raining then you have to deal with that as well so it’s complicated.

Dealing with cold and wet takes time, do shorter rides to figure out a system, make notes about conditions and what worked and what didn’t and you’ll figure out what works for you.


I tend to remain indoors when it gets below 2 or 3, because I feel the cold (especially in my hands and feet) at the best of times, and at c. freezing I just, well, freeze. I’m also pretty cautious about ice on roads after a couple of spills over the years. That said, one tip I would give is a coffee stop, if possible; a hot drink can really warm you (and perk you up) when it’s miserable.

This is excellent advice.

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I rode 100km on Sat in temps about 0c wearing my Castelli Alpha jacket and a single base layer. Very cold windchill but this was very effective and I usually really suffer in the cold - this has been a gamechanger for me!

Also key is headwear to keep the wind off and I also love my Castelli tights with the windproof panels in the front for days when the wind is a challenge.

Yes, it doesn’t sound like hypothermia — yet. But pushing through under these circumstances is IMHO not a good idea. Cycling should be fun and risking your health isn’t a good idea.

I only suffered from hypothermia once, during a ride last winter. Like you, I thought I was prepared. I was sure by rain and snow, with the temperature hovering around freezing. And freezing I was. I ended up in a supermarket, shaking uncontrollably for over an hour. Luckily, they sold cheap thermal undershirts. That saved me. Lesson learnt: always take spare clothes with you.

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Yup - these days I’d much rather ride with a small bar or frame bag in winter - there are so many options now for carrying spare kit without turning the bike into a sail. In the UK winter, it’s best to factor in some unexpected weather but also consider how you would keep warm if your ride was stopped by a mechanical or crash in the middle of nowhere.

My worst ever ride was only a 1 hour commute but as the temperature dropped it rained heavily for the first 30 minutes before changing to heavy snow - all that soaked clothing started to freeze. It took 5 minutes to unclip my backpack and get to my keys to open the garage. Honestly have no idea what I would have done with a puncture.


Yeah, I think that this was what did me in, too. Freezing rain and then freezing temperatures are the worst. I’d also add to your list of suggestions: consider off-road riding. The risk of injury due to e. g. black ice will be lower and riding in the snow is actually fun. Because you are slower, you’ll be closer to home. And if you fall, the consequences are much, much lower.

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Most people I know use more than two layers (+ waterproof) when it’s cold. Try adding at least a gilet, or wear both a summer and a winter jersey.

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