Originally Posted by
dailycommute
… For me the biggest problems emergeon extended winter riding, the body seems to start chilling down after a fewhours riding. Often post ride even in a warm house I will become chilled for20-30 minutes.
I find that often on my 14 mile commute on cold days, I become irresistably sleepy within about one hour of arrival. Fortunately at my job I can catch a brief microsleep to relieve myself.
BTW, speaking of relief, I have seen few threads in almost eight years reading BikeForums about this this off-topic winter commuting problem, somewhat related to winter dress: Cold Diuresis (there, I’ve said it). 
Originally Posted by
Jim from Boston
Originally Posted by
Sculptor7
Just came home from a 34 miler, an unseasonably chilly ride. Took more "natural breaks" than I can count. Felt like Austin Powers when they had just defrosted him.
If you’re discussing what I think it is, this topic was considered last winter on Fifty-Plus:
”Bladder control in cold weather riding!”
Originally Posted by Outside Magazine
What you’re experiencing is called cold diuresis,a phenomenon that occurs for reasons that are not entirely clear. One theory that remains popular—though it has been contested—explains how it works like this: When your temperature starts to drop, your body will attempt to reduce heat loss by constricting blood vessels and reducing blood flow to the surfaceof the skin. When that happens, your blood pressure will rise, because the same volume of blood is flowing through less space in your body. In response, your kidneys will pull out excess fluid to reduce your blood pressure, making you have to pee.
“A full bladder is a place for additional heat loss, so urinating will help conserve heat,” writes Rick Curtis, the director of Princeton University’s Outdoor Action Program…
Prior to googling this, I had thought that the above-described vascular constriction model was the mechanism.
Here in Massachusetts, there are stories (? urban legends) about scofflaws diuresing in public being tagged as Level I sex offenders. So one has to be careful….
Originally Posted by
wolfchild
Drinking enough fluids is just as important during cold winter as it is during hot summer. Dehydration can actually happen faster during winter then summer. You can be dehydrated and not even feel very thirsty.
Maybe so, but for my 1+ hour winter commute I cut back on drinking, including a morning coffee, and visit the porcelain receptacle, fully dressed, just before departure.