Yes, that's so true.. I had same experience in the beginning of the challenge. I found difficult to adjust my sleeping patterns. After little experimentation, I learned that 5 hour excellent quality sleep during night and 15 to 20 min. nap during a day is sufficient. Also I never push myself to the limit during exercise. I do what I can do without stretching myself too much. Also there is one side effect of Pranayama(breathing exercises in yoga) that you need less sleep, body recovers easily and fastly. whenever I feel some stress or fatigue, on that day I go to sleep early..
Thanks friend, really appreciate your concern.