Why does running in the cold slow you down

Oxygen binds tighter to hemoglobin in colder temperatures. When it is carried to your muscles, the oxygen is not transferred as efficiently to the cells. Therefore, your cells get less oxygen and produce less ATP. Simply, running the same pace in a colder environment is harder for your body all around.

How does the outside air temperature affect that? Is it that the oxygen you breathe in is so cold and significantly cooler as it moves along to muscle cells? I would think it would be around body temp once you breathe it in?

At what temperature would you say it become an issue?

Once I get warmed up, I run well in cool weather, assuming that I am properly clothed. In a race, warm-up time and extra clothing can play a role.

Interesting! I can honestly say that I have learned something new & useful on LR.

Does the inadequate transfer of oxygen from the blood to tissues during cold temperatures affect the brain as much as muscle? Just wondering, because I seem to feel mentally foggy more often post-runs in the winter vs. summer. I kind of like that feeling, though.

Is that all? Does the body not have to expend energy to keep the body temperature the same?

The extra clothing certainly plays a partial role in feeling slowed down.

Dont forget blood vessel constriction too. The cold air into the bodies core restricts the flow of blood.

Cold air is denser than warm air.

runnerMATON wrote:

Oxygen binds tighter to hemoglobin in colder temperatures. When it is carried to your muscles, the oxygen is not transferred as efficiently to the cells. Therefore, your cells get less oxygen and produce less ATP. Simply, running the same pace in a colder environment is harder for your body all around.

This might be true, but it doesn't matter in this case. Cold weather or not, your body is hanging pretty close to it's usual core temperature.

Mrs. M wrote:

The extra clothing certainly plays a partial role in feeling slowed down.

I can have as much as 8-10 lbs of clothing on (including sweat) after my run. That can easily be 15-20 seconds/mile. I ran a 5k yesterday that was 20° with 6-8 mph wind. I never felt warm despite 4+ miles warmup, full tights and a sweatshirt. I did run in trainers but was still at least 15 seconds a mile slower than 35° weather. I ran a 5k a couple summers ago that was 94° and only felt it cost me a few seconds per mile.

ripvanracer wrote:

Mrs. M wrote:

The extra clothing certainly plays a partial role in feeling slowed down.

I can have as much as 8-10 lbs of clothing on (including sweat) after my run. That can easily be 15-20 seconds/mile. I ran a 5k yesterday that was 20° with 6-8 mph wind. I never felt warm despite 4+ miles warmup, full tights and a sweatshirt. I did run in trainers but was still at least 15 seconds a mile slower than 35° weather. I ran a 5k a couple summers ago that was 94° and only felt it cost me a few seconds per mile.

Good God, what kind of tights and sweatshirt are you wearing that weighs 10 lbs? I ran a SLOW 4 miles today at 25 degree temp and was only wearing maybe 3 lbs of clothes. You need better winter gear.

So clothing issues aside, any other good explanations?

I've never noticed a slow down due to strictly temps. Winter winds, questionable footing and bad clothing might be some factors but does temp alone really slow you down?

Is this science or are you just going from personal experience?

Haji - I am going from personal experience but I imagine there has to be some science behind it.

I understand that some people are better at handling the cold mentally (or are more used to it because they train in cold weather) but take it to the extreme; do you think you can run as fast a 5k in 0 degree weather as you can in 50 degree weather (all other things being equal)?

OldYeller wrote:

Dont forget blood vessel constriction too. The cold air into the bodies core restricts the flow of blood.

Beat me to it

Does anyone find it hard to breathe while running in the cold (20's or below)? Today I especially had trouble breathing and my pattern felt very regular, especially while maintaining six thirties or faster.

Haji: I've never noticed a slow down due to strictly temps.

Last month I ran a pretty good 15k with temps in the mid-twenties and breezy; if the cold slowed me, it sure wasn't by much.

Aside from the winds, footing, and clothes you mention, I wonder if it might also be about winter rather than cold per se. There's so much less sun, and we stay inside and bundle up outside so we absorb very little of what there is. I've often felt sluggish and not very motivated to train after about mid-November - call it hibernation instinct, winter blahs, seasonal affective disorder, whatever. This year not so much, maybe thanks to vitamin D3 supplmentation and/or my "happy light" (actually Philips goLITE).

jo ho wrote:

ripvanracer wrote:

[quote]Mrs. M wrote:

The extra clothing certainly plays a partial role in feeling slowed down.

Good God, what kind of tights and sweatshirt are you wearing that weighs 10 lbs? I ran a SLOW 4 miles today at 25 degree temp and was only wearing maybe 3 lbs of clothes. You need better winter gear.

I didn't say I had that much clothing on for the race. The last time I went out for a training run, the windchill was about 0°. I had shorts, insulated sweats, tights, t-shirt, sweat shirt, sweat jacket and nylon shell. I would rather stay warm and sweat too much than freeze half the run. Half the difference in weight is the sweat that would have evaporated in the summer but gets soaked into the clothes under the shell in the winter.

Haji wrote:

I've never noticed a slow down due to strictly temps.

So then, have you raced in sub-0 temps? I am guessing not.

20s is not going to slow you down much but -20 will. (DUH)

To be fair, the OP mentioned 20 degrees.