Hi doctor, i m a 37 year old male, who for the past 6 weeks or so has had problems with sleep fragmentation. I find it easy to fall asleep, but wake up after approx. 1 1/2 hours, fall asleep again etc... I am a little stressed, and trying to solve that. All this started after a flu, and after I started doing cardio, but do not know if there is a relation. I have stopped exercising, and no luck.