You all can put those fabulous things on whenever! Just don't get smelly and dirty in them!
Just cause
They seemed interchangeable, but if you want a more logical explanation....
Psychologically,
Red triggers adrenaline in the body - which is why we use them for stop lights and signs, makes you alert and pay attention more - So since that trait is most often found in men (though not always of course), it seemed befitting.
Blue, on the other hand, has quite the opposite effect. It triggers nerves in your eyes that calm the mind and body...and therefore the color has been used to paint bridges that are high suicide risk in efforts to reduce those numbers, which they found it did!
*ahem* /RERAILING - non of those facts were my actually reasoning...but fun to know...