Mark - depends how big or small really.
I have worn Xerotherms which are too big for me without issue (cue small jokes about how all of them would be too big unless made for Barbie or action man).
Wearing ones which are too snug could present problems both in flexibility (hard to see really as the things really do stretch) but also in 'bare bits' when tops and bottom seperate leaving a bare midrif - which would be a bit chilly
