“Can I meditate 2 hours before sleeping, and only sleep 6 hours?
Any side effects of this?”
Maybe.
Meditation is different to sleep and the biological and psychological benefits of getting a full nights sleep are difficult to measure as precisely as meditate for X time then sleep for X time.
Everyone is unique in terms of the amount of sleep they need and how they meditate which makes the answer to this question unique to you.
To determine if you can sleep less if you meditate more, try meditating for 2 hours, go to sleep and see what time you wake up naturally without using an alarm to wake up.
Do this for at least a week and you will know if meditating more changes the length of time that you sleep for.
Edwin Leo 