My base layer is an off brand(Starter). It is 80% polyester & 20% spandex. It is not loose AT ALL. It fits tight to my skin and is sooooooooo dang warm.
Now..... since my accident back in December 2010, I have figured out a tested,tried & true method of staying warm. The accident severely forked w/ my internal thermostat. Somewhere at the back of your head is what controls your body temperature. That area of my skull was AFU. Several broken off fins on my spine as well.
Here is what my 7 years of trying to keep warm has gotten me. Even in the summer!!!!!
1. Shower immediately before going out and starting the sleds up.
2. Bar soap is by FAR the best.
3. Go over your body three times.
4. Pay even more attention to your feet. Don't just spend 5 seconds on a foot and call it good. I'm talking about massaging the feet w/ soap, between the toes.
5. Massaging those toes and feet is 1/2 of the process of keeping our feet warm. What this does is improve blood flow to those areas.
6. The other 1/2 is removing every single bit of oil & sweat from every crack & crevice. Here's a few analogies.
A. Oily welding gloves transfers more heat to your hands than non oily and soiled gloves. In our case, it transfers the cold.
B. Sweat(wetness) intensifies cold.
C. Wet gloves obviously makes you miserable.
7. Get every last gram of sweat,grime,oil & schmegma off of your body.