It turns out that the situation in organ playing is quite similar. When the going gets tough or boring, many organists switch to something else. It's human nature.
But if you have a friend or a partner who is on the same path you are, exercising together might be very pleasant. You sweat together, you share the same activity, you motivate one another to get out and work out at the same predetermined time. This way your motivation to exercise might last much longer - at least long enough to start seeing real results.
How about finding a friend or a family member to practice organ together? You could literally play organ duets or your partner might play another instrument or sing. It could be as simple as singing hymns or as advanced as playing 4 hand piano arrangements of classical symphonies and opera overtures on the organ and anything in between (including classical solo organ music with parts divided between the two people).
When we make music together, a real magic happens.