I am an older woman in  an Arthritis water exercise class and we are in a shallow pool, so often when we are wet and standing its cold.  Several people in my class wear a t-shirt or rashguard in order not to feel the cold as much.  Women's rash shirts are way more expensive then mens and since it wasn't a syle competition, i bought this mans rash shirt.  I'm heavy, but not huge and mens T-shirts in XL is plenty for me.  That's what i ordered the first time.  Skin tight! so I returned it and ordered XXL.  Huge, baggy, too long.  Gets in my way in the water, so now I'm gong to give it to a male friend.  Warning sizes don't seem very accurate.