1/3/14 8:50 PM

I did a 30 miler in pretty cold conditions yesterday.
I seem to have slept way more soundly [like a rock] last night than even after 50+ miler in season.

Any correlation ?

1/3/14 10:13 PM

...trying to stay warm.

1/4/14 12:04 AM

Maybe a human "hibernation reflex" left over from prehistoric times?

Cold weather sure makes me feel more like sleeping than going outside at least.

1/4/14 6:17 PM

I hadn't slept that well all year... ;) Or all last year I don't think...

1/4/14 7:28 PM

I NEVER sleep well. Exhausted or not as I have mentioned here before. I ran 10k in 34F yesterday and got about 3.5 hours of true sleep last night. :(

I did see a well done movie, The Reader. Which is not my normal genre.

1/4/14 7:52 PM

It is a fallacy that our bodies "burn a lot more energy trying to stay warm in cold weather." If you are sweating while exercising, that means that your body is producing more heat than it needs to maintain temperature (true in nearly all circumstances). So we don't burn more energy trying to stay warm.

We do burn more energy trying to maintain the same speed as the temperature drops (about 1% more effort for every 5 F/3 C drop in temperature).

1/4/14 8:22 PM

Eric, do you eat a full-size meal within a couple of hours of retiring?

I've known folks whose work/commute hours had them doing this, and they didn't sleep so well.
I've been there as well, since my digestive function somewhat "freezes up" at times during what would otherwise be a comfortable night's sleep.
I hate when that happens(!), but have resigned myself to retiring earlier and then getting my bed rest in deliberate 2-3hr intervals, with perhaps a snack and or a small bit of light exercise or housework between intervals.
When this is needed, and works, it's magic, and the newspaper is already on the table in the morning (if not already read, too).

1/4/14 9:51 PM

did you break a sweat on that "cold" ride?

"So we don't burn more energy trying to stay warm. "

taken literally, this is false. just sitting in the cold, our bodies will shiver to maintain core temps as needed. shivering burns more energy than not shivering.

now if we're *exercising* vigorously enough to sweat profusely, then yeah i agree with it. but i'd imagine there's a fairly broad gray area between the 2 extremes. is exercising enough just to sweat a litte enough to preclude any additional energy burn to maintain core temps?

i've ridden many times in the brutal cold hard enough to sweat a little, but my extremities were chilled to the bone. i'd have to imagine there'd be some sort of physiological response to burn more energy to try to build heat beyond the exerecise. but that's just a hunch.

1/4/14 11:00 PM

I was playing zipper polo for about 12 miles and then was zipped up tight for the remainder. Some sun early and then between angle of sun and then clouds it felt a lot colder. I was not cold per say for the remainder, but not motivated to unzip even a little. ;)

1/5/14 11:51 AM

You burn some extra calories in cold weather, if well, you are cold. You also burn more calories in hot weather as ther is extra energy expended to keep yourself cool/sweating. Nothing new here.

One less obvious item to consider is that your body expends more energy to warm/keep the body warm while breathing in cold air. You may be sweating, but you are still expending extra energy to warm the air breathed. I'm not sure how significant this consideration is. What is significant is that I tend to work harder in colder weather than in milder temps to make up for the decreased performance breathing cold air. With that I burn more calories.

1/5/14 8:18 PM

Again, if you are sweating then your body is producing more heat than it needs to maintain thermo stasis. Warming the cold air coming into your lungs means that you will sweat less than you otherwise would have because some of the excess heat your body produces goes to heating the air rather than to sweating.

The physiological response to cold extremities is that your body "saves the core" by restricting blood flow to the extremities. I have gotten mild frostbite while exercising outside because I did not produce enough core heat to overcome this response. If you are not producing enough heat through exercise then your body enforces exercise - it shivers. If you're not shivering, then your body is not perceiving that it needs to warm itself, at least not substantially.

1/6/14 8:59 AM

After a 3 mile jog in 20 degree weather, despite being properly dressed and feeling fine while running, I was chilled to the bone and never really felt warm the rest of the day. My body just wanted to crawl under the covers and take a nap.

1/6/14 9:50 AM

True. Sweating or shivering results in greater calorie expenditure. If you are not doing either, but exercising in cold weather, there is still more energy expended warming the air you breathe. If not, then you are cycling harder with less oxygen absorption/consumption to maintain the same speed.

Extra cycling clothing {weight, drag, hobbling/cumbersomeness} and the denser cold air resistance means more work/calorie expenditure to maintain the same speed/performance in warmer temps.