We have a mind and a body, and when we feel that neither is getting used, we get depressed.
That might be not going to the gym for a few days and starting to feel doughy. Staying inside a whole day and moving barely your fingers to press “Next" on your Netflix account. Or working from home all day without taking a walk here and there.
Or in terms of the mind, it might mean working a job where you don’t feel utilized to your highest potential. It might mean not having a job at all and feeling like a useless piece of human flesh staying at home all day and getting away with doing nothing.
Whatever it is, you need to find stimulation for the brain and body.
Move your body: join a community rec-league and play a sport, or get to the gym and work out. You can simply commit to a walk/run to the grocery store, local park, river, etc. at least 3 times a day to get out of your house.
Exercise your mind: get a job that makes you feel fulfilled to come in, whether it’s the people, the purpose, or the activity. If you don’t have a job, start a project that gives you a mission in life.
These two things need to be stimulated regularly and I’ve seen people who have abandoned both mind and body. They become extremely lethargic, and it’s disappointing. Both of these also work in tandem so when you neglect one, you neglect the other as well.
Exercise both mind and body.