Flight tips: How to stop your legs from going numb?

Just like the title says! I have taken my fair share of long-haul flights over the years but recently i've developed this issue where my legs will go numb, it's become so uncomfortable that I can't sleep. I've tried to elevate my legs more to alleviate this but it's pretty tough in economy. I am 5'3 and usually i rest my feet on my personal item under the seat but that doesn't seem to help enough.

I have a 8 hour redeye coming up and i'm looking for ways to prevent this. I've seen those foot hammocks but i'm worried I would bother the person sitting in front of me.