Sleep - how much do you get?

[AC123]

How much sleep do you get? Do you think you can be "trained" to have enough sleep in under 8 hours or is everyone just wired up differently?

I'm incredibly grumpy if I don't get enough sleep.

Do plenty of exercise and eat well, sometimes I just can't get to sleep though as I have a habit of overthinking things when I'm trying to drift off! Never have a coffee late/at the weekends which doesn't seem to make much difference.

I'd like to be more productive and sleep less.