In which my body clock is inconvenient

Leaving aside the inordinate amount of sleep I always need except in high summer.  6.15am?  Too early.  6.45am?  No problem.  A minor inconvenience, really, but given that I have to get up at 5.45, that extra hour makes the difference.  Right before lunch, I suddenly get an amazing burst of speedy wakefulness and productivity - just as I get too hungry to work anymore.  By 7 in the evening I could go to sleep right then and there.  Woe betide me if I'm not asleep by 11pm though, because suddenly?  I have loads of energy and a need to work out to pumping dance music.  Since that option isn't available to me right now, well here I am.  *Sigh*