[jamesqf]

May I suggest looking at the thread about taking your horse for a walk? Here: http://www.horseforum.com/trail-riding/taking-your-horse-walk-37485/ Maybe when you go out to "ride" for an hour, you start with 5 minutes on the horse, and the rest walking. Then increase the riding gradually as you learn what the horse can handle, and as you both gain condition and perhaps lose weight.