This is a notion not well understood.
Active Rest.
Complete oxymoron at first glance. A paradox even.
Here's a simple way to describe it:
Let's say that you break your leg. You know that you should not be walking on it afterwards. You know that you should keep your cast on for the amount of time your doctor tells you to leave it on, even if the pain has subsided.
Once you are cleared to be active, you take it easy at first. Perhaps you have a big tournament coming up in which you would like to be fully capable of participating, but there are several league games before said tournament. So instead of jumping back in full-force in the league games, and even though you feel entirely healed, you practice active rest to give yourself the time to heal even better. Every moment not playing league games is difficult. You are purposely holding yourself back and requiring intense self-control to rest.
Folks, like myself, with chronic illness need to practice active rest on a regular basis. If we have something big* coming up, or if we just did something big, even if we feel decent, we need to rest. We may feel as though we could accomplish something, but we force ourselves to stay in bed or at home to rest. To recuperate. To prepare. Actively resting is not as delightful as it sounds when there is illness involved. It's not as though the pain evaporates if we are lying in bed. We all have to remember that pain with chronic illness is often constant. Severity of pain and nausea obviously vary from day to day, but for me, there has not been more than a few days over the last 18 years where I have had zero pain (and even if I do experience a day with zero pain in one illness, I have about 10 more that are waiting on the bench to jump in and fill in that void of pain).
Rest days are not always bubble baths and face masks and calming music. It is actively preventing ourselves from flaring up our illnesses to a point of being unable to function for weeks or months at a time. It is taking as much medication as our body requires, even if we do not want to do so. It is allowing our bodies to recover. It means saying no to social events and date nights. It means leaving the vacuuming or the dishes an extra day or two. It means constantly putting off chores and events and social engagements because we know that we don't have the energy to do everything around the house, everything for appointments, everything for injections, AND every social event.
For me, personally, if I get two things done in one day, that's a big day for me. If I can manage to empty the dishwasher AND do a load of laundry - awesome! If I can throw the ball for Decker AND go to an appointment - awesome.
And in between these 'busy' days, I rest.
Purposely, begrudgingly, uncomfortably, I rest.
Actively resting is not always comfortable. It often leaves you feeling guilty of being lazy, even though you are simply listening to your angry body. You lie there resting even though you are restless and want to do something. It takes more than just self-awareness, it takes a lot of self-control.
If I didn't practice active rest, I would wind up in the emergency room all the time for severe flare-ups that cannot be dealt with at home.
So make sure to practice active rest - and know that it is exactly what you should be doing.
*a big event would be maybe a date night with dinner out, a long drive to an appointment, getting bloodwork done, a procedure, or even just a simple injection. Getting groceries or going shopping (for me) constitute colossal events.