That depends on the individual.
10
You should never sleep with an eletric blanket.
If the pain of sleeping on it is tolerable then it should be ok to sleep on it.
Kids
5 hours a day
Definitely not. There's a number of things that could happen to you while running away, and, being that Percy Jackson is fictional, would be a waste of time.
A fourteen year old should get nine hours of sleep each night.
Typically 8-11 Hours.
for 8 Hrs
8-10 hours.
6 to 8 hours
you should get on average 8 hours of sleep if you are a growing teenager.