makes sense, youre working your body harder so it needs more rest. thats how my body responded too. since i started working out id get sleepier at night and sleep harder THRU the night. when i had insomnia mostly it was from not being as physically active during the day (not working, sitting around, resting, etc). as soon as i demanded my body to work harder, i slept like a baby (who sleeps thru the night ! haha)