So.. I've run up against a problem this year. I'm not sure of the cause other than not enough calories (or not enough of the right kind of calories) plus the added stress of my body trying to keep itself warm AND keep my legs moving. The problem is that yesterday I almost passed out from exhaustion. I didn't feel better till today I didn't ride my usual commute to work but kept almost the usual intake of calories.

So I'm chalking this up as an almost bonk from acute calorie deficiency.

this didn't happen last year so I'm rather confused.

Thoughts? Anyone else ever have this happen while winter- riding? Suggestions?

Interesting topic considering my latest observations. I am unsure of your experience level with winter riding. I am entering my 4th winter of almost daily riding, regardless of conditions. I usually leave early in the morning for a 20-25 mile mountain bike on rock roads, this time of year.

I have one very common route that i ride in both winter and summer. It is about 22 miles and in the Summer it takes me around 1 hr and 30 minutes normally. Today, and a few of the other recent cold days it has taken around 1 hour and 45 minutes.

It is well known that travel is slower in the cold temps. Many reasons are given but none is particularly well proven. What i can tell you is that not only is winter riding slower, but it also consumes more energy, substantially more in some cases.

I am pretty tired this evening. The last several mornings have been our coldest so far this year. This morning was 24 F, and again i was riding for 1 hr. 45 minutes. I suspect that there are other biological factors involved that probably no one knows about. I just always have a bit less energy when the daylight hours start to fade. Perhaps our bodies are more reticent to spend energy and more apt to try and conserve it? Whatever the cause, i think what you are feeling is normal.

From my experience cycling in the cold requires a bit more energy than cycling in warmer temps, for a variety of possible reasons.

If you normally consume approx. 250 calories per hour out there in the summer, it probably wouldn't hurt to up that to about 300 calories per hour.

Severian,

I have this problem where I think I can go out and ride as fast as when it's warm but my system just can't be pushed as much in the cold weather. Eating could be part of it. But I think it mostly has to do with the fact that I usually drop down to 2-3 hours riding per week instead of 5 -8. And for some reason my system just is not as efficient in the cold. I really noticed this when the tempertures dropped below about 65 degrees F.

You might also try to dress just a touch warmer (not too much). I have found that if my body feels cold it will never performe well no matter how hard I work out.

It's also possible that you have caught a mild cold and it only shows in exertion fatique.

I'm less inclined to increase calories. Consider how much more inactive a person is off the bike in winter months. No more yard work, ball games, swimming etc. to burn the extra off. That's why everybody packs on pounds all winter long.

I rode till just before the first snow last year and started up again when the morning temperature jumped above freezing and last year was my first year of long-commute. Typically I'm carrying about 10 lbs worth of gear to and from work (which probably has something to do with it) in a courier bag.

On the flip side I am also a trained and training martial artist and this has caused a change this year. My last belt test I severely overstressed the muscles in the right side of my back which as made my WHOLE life difficult. The training is between 3 and 5 hours a week so that's something.

The other change is that my old bicycle (a Gary Fisher mountain bike w/ commuter tires, 15 years old) is rear-wheel less so I've been riding my roadie.

I'm definitely planning on getting tights and wind pants but my current gear is more than adiquate for cold conditions. Double jackets (one wind one insulation), baselayer shirt, hat, helmet cover, ski goggles and face mask for sub-freezing temperatures, doubled gloves, cargo pants, leggings and shoe covers. What really gets cold on me (unfortunately) are my nethers but not more cold than they used to be. and I HAVE rode in sub-freezing temperatures for longer.

It depends on how much the conditions changed from what kind of riding you have been doing. But it's a lot more work to do the same speed or the same distance in the cold. Did it get a lot colder all of a sudden? Did you try to keep the same pace as if it was a lot warmer?

You may have to just take it easier than you thought until you get used to it. Go slower if you have to. This would have happened to me a few times but I already was very familar with pre bonk symptoms. I think you have it right.

I've noticed that exhaustion can sneak up on me in the cold. For me the threat is dehydration more than loss of calories. Most people lose a lot more moisture through sweat than they realize in the cold, because it tends to evaporate fast. Plus, in the freezing they don't tend to have water bottles or hydration packs ready and they don't feel like downing a big jug of cold water at ten degrees.

Was there a lot of snow/ice on the path? Either of these can increase your effort/distance travelled. I find that I need more calories when the temp is colder. A function of more work and a harsher environment.

Instead you need more calories during and afer the ride. Your total calores for the day could actually be the same.

When it's below 40F, my water bottle gets pretty cold and sometimes even freezes partially. I find it hard to drink when it's cold.

Did you ever try a stainless vacumm insulated bottle? It will keep water from freezing all day. In 25f temps.

Might be a good thing to try.

Around $20 to $29 most places. https://thermos.smartermall.com/searc....asp?dept_id=3