kapalabhati

i am a male yoga student and teacher and would be very interested to hear an experienced womans point of view on kapalabhati.I have some very old notes from bks Iyengar where he mentions that ladies should be aware of kapalabhati and bhastrika pranayama that it can cause the breasts to lose their firmness and droop.Anatomically I can see how this could occur and I know mr Iyengar would not have said this unless he through his years of experience had observed or learnt this himself from his teachings and feedback from students.I would be keen to find out from long term practitioners of bikram yoga if they find this has been the case,as I know this is a part of their regular practice. peter