From a scientific point of view, is it a good thing to exercise cold? I mean, even if one feels warms to oneself, if the exterior of the body is cold, wouldn’t that diminish gains from exercise?

I ask partly because I would personally rather feel uncomfortably warm than cold, and so tend to cover up more, and partly because I have seen a number of runners (especially, but some cyclists too) of both sexes out with nothing but shorts and a short-sleeved top, yet with skin red and ‘googsebumpy’ from cold and their breath visible, and I feel cold just looking at them.

So, what matters? How you feel in the cold? Or how cold you actually are?

As a competitive runner I would never “compete” cold but I may start cold. For example after warming up with layers on etc and in the coldest of conditions (Think minus temperatures on ground covered in snow/ice and frozen solid) during the cross country season for example its typical for 90+% of the field to run in vest and shorts. Some people wear hats and I wear thin gloves but once warmed up and in full competitive mode you dont feel cold. At the finish get warm layers on again.

In training I would typically wear layers as you dont generate as much heat as racing but its down to comfort. I dont tend to get very warm in training so often wear tights or Ron Hills everyday during training in the winter with maybe a couple of layers on top and gloves.

Overheating is more detremental to performance than being slightly cold.

http://sciencenordic.com/hot-brains-impair-athletic-performance

Other content is google-able.

I was under the impression that if you are under-insulated your body has to put more energy into keeping its core warm thereby leaving less for its muscles. Also if you are cold your body will withdraw blood from your extremeties to preserve the core, which would also reduce blood flow the muscles. I would assume then that you won’t ride as well, so you won’t train as well.

However, in the case of the runners you saw, it is perfectly possible to for your skin to be cold whilst being hot inside. If you are generating a lot of heat, you might need really cold skin to be able to dissipate the heat.

I’m in the cold camp. Overheating is clearly detrimental to my performance, that has been clear on many occasions. It’s also well known that distance runners need to lose a lot of heat. (Perhaps less obvious for cycling where the wind cooling is stronger). Mind you it must be possible to get too cold, especially a long event when you are not going flat out.

I get properly hot when I exercise so often wear less than most other riders. I’d rather feel comfortable than conform to someone else’s view of the weather and be unbearably hot – that’s what mums do to kids. I do notice that I slow up in the cold though, but I’d rather lose a few commuting races than boil in the bag.

I think I’ve only been too cold once while running – and that was in February up a mountain in near gale-force winds, and I underestimated the wind chill. But usually? The cold’s not a problem. I like to be slightly chilly at the start, then warm up.

I do notice that I slow up in the cold though

Really? I find it’s heat that’s the problem: while I keep running through summer here (in Madrid – it’s not cold!), my pace drops massively compared to winter.

A hot day in Madrid is a bit different to a hot day in leafy Surrey though.

Sometimes I do wonder if I should cover my legs in winter, they don’t feel cold whilst riding though.