agree2, sleep less you'll get a headache. sleep longer you'll also get a headache. i tried when i was having my exams, duration of it was like 2 weeks. everyday slept for about 2~4 hours. in the end when i was gonna sit for my last paper my eyes was so red.

last time during kindergarten i still remember i slept i think more than 10 hours per day, then primary n secondary 8 hours per day. now college 6 hours per day. working ? lesser i guess?