Undergarments for your breathable chest waders that is......get yer minds out of the gutter

I usually just wear sweat pants under my lightweight breathables. Part of why I like them is they are loose and comfortable but the obvious downside is they(being made of cotton) wick water so are prone to dampness when you work up a sweat.

I'm not well versed on other materials/brands that breath better and wick away water better. I picture something like longjohn bottoms but made of a breathable material like gor-tex or something. My concern there is as the temps. warm up yet still to cold for shorts/tennis shoes. Will this type of undergarment be "suffocating" and promote overheating of oneself on a long river hike?

Opinions and recommendations needed.

Thanks.