I've always wondered if it really got harder to ride in the winter

so what ? You can only ride now, so get on with it!

how would you know ?

Sigh.. you must think I am stupid barnes.. really.

It was on a documentary on telly. Your CORE temperature is 38whatever but your limbs aren't necessarily at all. Ever had really cold hands that you can't do anything with? Ever descended on a winters day and have your face go all stiff cos your facial muscles have got too cold?

your leg muscles will be putting out another 800W of heat, ie 8 times your rest metabolic rate, and your blood will distribute that heat over the surface of your body to prevent overheating

Well aside from the fact that, at lower power your body's probably more efficient than that, but what do you think the rate of heat loss is per unit area of skin whilst whipping along with a single piece of fuzzy lycra between it and -2 C air at 20mph? How fast does the blood move around your body, so what's the heat flux from say your frozen cold toes to your core? No? So why would 800W be plenty of heat?

Ever had really cold hands that you can't do anything with? Ever descended on a winters day and have your face go all stiff cos your facial muscles have got too cold?

cold skin, yes

but what do you think the rate of heat loss is per unit area of skin whilst whipping along with a single piece of fuzzy lycra between it and -2 C air at 20mph?

fuzzy lycra ? Isn't that for tarts ? I always ride in shorts, yet can testify that I was far too hot yesterday in the conditions you describe, leading me to believe that I wasn't dissipating all that heat from my legs

How fast does the blood move around your body

well, I have no idea, but it must be quite fast to transport all that extra oxygen to the muscles as I'm breathing about 20 times harder when pedalling hard than when resting. Also I don't count fingers, toes and face as limbs…

I read somewhere that the optimum ambient temperature for peak performance is 17degC, as that is when your muscles are all warm enough to function. I guess that means that the colder it gets, the harder it is to maintain performance. Plus with extra layers it is harder to move (running in leggigs is definitely slower than running in shorts (for me anyway).

I am surprised no one has mentioned the rolling resistance increase from the cold air in your tyres. Everyone knows that cold tyres roll slower than warm ones (think squash ball – it only works when it's warm – up to that point it is much slower).

Of course the above post about rolling resistance increase of tyres when cold is almost certainly bo!!0xxs, but it will probably get the pedants going

cold skin, yes

Cold skin stops your full temperature muscles from working? That makes a lot of sense NOT.

Fact remains your limbs run colder than your body core and fluctuates more. That's why they call it core temperature, and why they take it in your mouth or up your arse, and not in say your elbow or knee.

as that is when your muscles are all warm enough to function

that assumes the muscles are passive, which doesn't even apply to cold blooded creatures. Note that the temperature inside your body is set by your autonomic system and not by the air temperature.

Yes. Hate the cold weather.

Hands freeze despite proper gloves. Lungs hurt from the cold air, teeth hurt, get bad ear-ache. Did I mention that I hate it?

Did I mention that I love it?

Simon – you can end up with cold muscles even when peddling hard. Its a complex thing to do with rates of heat loss and so on but it is easily possible. Basic physics and biology. As you say you might be generating 800 w of heat – but you could be losing 900.

As for being slower in the cold – I have not noticed it. Are you having very mild exercise asthma? Lower O2 uptake? Its the only thing I can think of is that your lungs are going into spasm or that you rare not breathing deeply.

Note that the temperature inside your body is set by your autonomic system and not by the air temperature.

Oh right. So hypothermia is a disorder of the central nervous system then? And I thought it was because of heat loss due to environmental factors! Are you telling me that when I'm cold it's cos I am imagining it?

Simon you are well wrong this time. Even TJ agrees with me!

Back to the anecdotal evidence.. I have beaten better riders than me on climbs when they were under-dressed and I wasn't. Keeping warm takes energy, so if your core is cold ie you're under dressed, you have to use more energy to stay alive and less is available for biking with 🙂

But seriously. Try more clothing on legs and see if it helps.

So hypothermia is a disorder of the central nervous system then?

no, that's when the autonomic system breaks down

Simon – you can end up with cold muscles even when peddling hard. Its a complex thing to do with rates of heat loss and so on but it is easily possible. Basic physics and biology.

I think you'll have to do more than merely assert that it's physics. The muscles are generating the heat.

Keeping warm takes energy, so if your core is cold ie you're under dressed, you have to use more energy to stay alive and less is available for biking with

Bollocks. Apart from the basal metabolism running digestion and cell maintenance, the brain etc, if you want to generate more heat you have to operate the muscles (eg shivering), or some other physical activity like er, pedalling.

Try more clothing on legs and see if it helps.

it's not me with the problem, I get too hot despite wearing shorts 🙂

Simon – if you are losing heat faster than you generate it you get cold. its as simple as that – including your muscles. Thats what hypothermia is. You can exercise as hard as you like but if you are not generating enough heat to counteract the loss you get cold – even in the centre of the muscles. its a simple matter of heat in / heat out.

consider an extreme case – being in sub zero sea water You die of cold in a few minutes no matter what you do as you are losing heat faster than you generate it.

Simon – if you are losing heat faster than you generate it you get cold. its as simple as that – including your muscles. Thats what hypothermia is

obviously, and I've had it, but that's not what we're talking about. This about people feeling it's harder to ride in the cold, which I believe to be psychosomatic. I was on top of Helvellyn in high wind in shorts in November, and had to stop for a flattie, and in a few minutes, stationary, I got too cold. It wouldn't have happened if I'd kept moving and generating heat.

which I believe to be psychosomatic

No. You might be a god on earth but the rest of us mortals are affected by cold. Your experiences are a sample of ONE and can be in no way representative of the human population, can it?

Try more clothing on legs and see if it helps.

it's not me with the problem, I get too hot despite wearing shorts

So clearly and GLARINGLY obviously I wasn't f**king well addressing you then was I?! Good god man.

Apart from the basal metabolism running digestion and cell maintenance

So, apart from the things that your body does to generate heat, you don't generate any heat… Simon you clearly know absolutely f*** all about metabolism or apparently physics. So why are you commenting so much on a thread about these two things?

Ever wondered why one tends to eat less in summer? Why things like salads are culturally considered summer food and hearty fatty proteiny things winter food?

Your experiences are a sample of ONE and can be in no way representative of the human population, can it?

why thank you 🙂 But I believe myself to be quite ordinary – the only difference being I like to work things out for myself rather than just accepting what everyone else tells me…

So clearly and GLARINGLY obviously I wasn't f**king well addressing you then was I?! Good god man.

not obvious to me :o)

So, apart from the things that your body does to generate heat, you don't generate any heat

well, it doesn't arrive from hyperspace – but I don't know that the body has much scope for generating more heat just by sitting there and turning up the wick on the boiler (whatever that may be) which is why we shiver when we're cold to generate muscle heat – but the muscles are good at making heat as they're only about 20% efficient at turning food calories into mechanical power – though quite an achievement given the low termperature at which it's carried out

Simon you clearly know absolutely f*** all about metabolism or apparently physics.

that remains to be seen

I don't think it's useful to declare that "physics" says I'm wrong without actual stating which bit – there's a lot of physics.

the only difference being I like to work things out for myself rather than just accepting what everyone else tells me…

And I don't? From where I sit, you're not trying to work things out for yourself or learn or read up on things, you're jsut reiterating what you tihnk you know. Did you do any reading around for this "debate"? I certainly did but didn't find anythign directly citable.

Your body does have an internal thermostat which it can vary in addition to heat generated by shivering etc I believe, although I could be wrong.

And I didn't declare that physics said you were wrong, I said you didn't seem to know much about it.

This thread has gone way beyond anythign that coul dbe described as a useful application of technology so I think I'm going to leave it. Do some reading.

Quite apart from SFB being an argumentative cock as usual, yes, I've noticed that on a warm summers evening I veritably fly home, but do the same ruote a few dayslater with a chill in the air and it's like someone's raide the top of the hill to make it steeper. Might be psychological, might be physical, but I'm glad i'm not the only one to have noticed it.

I said you didn't seem to know much about it

you were guessing

This thread has gone way beyond anythign that coul dbe described as a useful application of technology

was it ever about that? I thought it was about people feeling slower in winter and pretending their muscles must be cold and so don't work as well when in fact they'll only be cold when they're at death's door. I'm not sure what I need to read about us having blood at 38C…