What 's the difference between working all night until 4am and waking up at 12pm and going to sleep at 10pm and waking up to work at 5am ?
Being an ` owl ' , I usually go to sleep at 11pm-1am , but very rarely , I wake up early -LRB- e.g. 5am -RRB- and feel kind of a euphoria and rise of productivity , which lasts until afternoon . Is there any medical reason for that euphoria ?