If we’re at a place where we have a pen big enough for our horses to move around, (I help a ride manager put on rides, so she usually has big pens for her horses), I don’t normally do anything for them. Horses will generally move around enough at night to keep their circulation going and keep them from stocking up.
If we are at a ride where they’re tied up at the trailer, I like to put standing bandages on them after a ride, particularly with mud underneath. it’s a habit I learned as a groom on the racetrack . Saratoga is right, walking the horses, often, is a very good thing, if they are tied to the trailer. Every couple of hours is great, and if you don’t feel like getting up in the middle of the night to do it, take them on a walk as soon as you get up, well before you tack them up for the next day’s ride, then warm them up well before you start!