get yourself some "rashies". those are the shirts that go between you and a wetsuit. surfers where them because it's hard to get sunscreen/block to stay on when your out in the water all day. they work great at keeping the sun off you, you keep cool cause it wicks and they are designed to get wet so sweating in them is just perfect. just don't put them in the drier after washing them as they will retain your scent. line dry only, which isn't a big deal as they dry in 15 - 20 min anyway.

btw they don't work well at keeping you warm so don't expect them to. they are for hot weather only. wind also goes right through them. great when it's hot. crap when it's cold. they don't even work well as a base layer even though they wick really well they are not designed to hold heat.

cheers
kat