Higher heart rate while running in cold

[SunsetRunner]

Hi there, 

I've noticed that my heart rate is quite higher during running compared to summer. 

In mild temperatures my heart rate ranges 133-147, while at the same pace I reach 153-168 during winter. 

Now, I'm asking myself wether my heart rate actually goes up this much during winter exercises or rather this is an error in measurement (I read about less blood flow to the periphere of the body in colder temperatures and 'cause smartwatches only estimate your heart rate using blood flow in the wrist, this could give inaccurate numbers). Someone experiences this as well or knows the answer?

I'm asking myself wether I should just keep running my normal distance and pace or I should go more slowly and do shorter runs (I normally do 10km at 6min/km, already for more than a year).

I don't notice any change physically. Exercises just feel quite the same as before. So subjectively, I don't experience my heart rate going up compared to before. But on the other hand, wouldn't wanna put too much pressure on my heart by training at peak levels. 

[Heybales]

The less blood flow to extremities is effect when the body feels threatened by cold and is conserving the heat rather than letting it escape on surface areas.

That shouldn't be a problem once warmed up slightly.

Actually body is probably trying to keep those areas warm and is fighting against the heat released easier by increasing blood flow - aka heart beat faster.

Accuracy on the optical method of reading HR will always go the other direction for errors, it will miss beats, it will cut off at some max and not go higher.

If this was electrical chest strap yes static electricity with poly shirts and dry air can cause inflated readings and bad spikes.

And this is exactly why HR can be a decent calculation for calories, and why in summer heat and winter cold it can be a bad one.

As you observed - doesn't feel harder at same pace. And it's not - your HR being higher has nothing to do with the actual intensity, but other reasons.

Therefore you are not burning more calories.

And if you were to be training by HR zones - you'd be in the wrong zone for your actual effort.

This is why pro-cyclists train by power (watts) not by HR. HR can be skewed for many reasons that have nothing to do with level of effort, and would make for bad training days.

So keep it up.

I hit those fall temps and saw the fact my summer inflated HR was around 10-15 higher.

I haven't noticed it for winter yet, probably because I'm fighting stupid static spikes it seems like.

Or I'm dressed cold enough and I don't need elevated for getting the heat out.

I'll have to compare - I've have 32 F day I was underdressed and very cold hands and arms and never started sweating, and a too warmly dressed day. Mostly I start to sweat though so warm enough.