I did it for about a year a few years ago..and loved it!!! the only hazard i could think of for CFers is the possible dehydration...but they let you take water in with you. i became so hard core that my friends who came to class had to lie down and i kept on goin'!
i posted about this awhile back--was thinking about getting back into yoga but i think i'm going to continue my running regime.
be forewarned, though---one glass of wine after yoga will knock you out!<img src="i/expressions/face-icon-small-happy.gif" border="0">