Us flat out types tend to sweat a bit. Or a lot. My handlebars were getting really slippery one morning last week; it turned out that my gloves were totally saturated with sweat, and they were slipping on the sweat that was squishing out of them. The sweat in turn had run down my arms inside my jacket. I read a nice little description of "breathable" fabrics - you can either get wet from the outside in, or you can get wet from the inside out. One is cold and wet, and the other is warm and wet. In winter, I prefer the warm and wet option, even if it does mean slippery gloves.
Sweat eventually means smell. It doesn't matter if I wash my kit every night - enough residue builds up over time to produce a rather nasty tang. It's worse in winter, funnily enough, as the clothes don't have an opportunity to dry out as they would on a stinking hot day. Instead, they fester.
I was at my wits end last week, and then someone suggested soaking them in baking soda. I had no idea how much to use, so I threw half a cup in a bucket of cold water and threw the kit in to soak overnight. Then I washed it all as per normal.
Amazing. No more stench.