Yes, especially if you're posting. If you get to cantering and jumping then you're getting a real workout, which is why I actually log my riding.
This is data from my fitbit. The top one is today, with a lesson starting at 7 PM. The bottom one is the Bumble which started at Noon. (I did some short hiking later in the day which are the other spikes.) Efforts don't look that different, do they?