How much is too much riding

[guest@endurance.net]

Debbie  devitaphoto@boone.net
How much is too much riding.  I have an arab whom around Christmas started
dropping weight.  The vet checked him over and it has been concluded I
ride too much. How much is too much.  How much do other people ride their
horses. How many times a week, how long at what pace. How many days do
they give the horses off?  I want to do good my my equine partner.  I
don't want to over do it and I don't want to under do it either.  Any
sugestions?