Planning down time into your schedule is as important as any other task or event you could put on your calendar.
Productivity is stressful.
Down time allows you to stop spinning on the wheel of productivity for a little while in order to recuperate, put your brain into a less active mode, decompress and lower your stress.
Depending on what exactly you do in the day and what your daily work involves, this could involve anything from a walk in a nearby wood, to sitting on the sofa catching up with a TV programme. I try not to read during down time as I don’t want to use a lot of brain power during this time.
The point is – schedule something easy that you can mindlessly do a couple of times a day. This helps with motivation and may reduce your chances of being burned out and eventually exhausted by your taxing schedule.