I think it's related to the notion that depression (and burnout and other chronic states of negative emotion and low energy) is caused by a lack of optimism - or a lack of things to feel optimistic about.
From an evolutionary point of view, if we're not inspired and excited about what we're doing now or what we expect to be doing in the near future, it makes sense to go into energy conservation/restoration mode and go to sleep.
Similarly, over the long term, if we aren't inspired by the life we see ahead of us, it's best to go into energy preservation and contemplation mode while we try to figure out how to get onto a better path (and if we can't find one, we end up in chronic/deep depression/despair).
I've overcome depression (and come off meds) by developing/learning techniques for finding optimism any time things seem bleak.
From an evolutionary point of view, if we're not inspired and excited about what we're doing now or what we expect to be doing in the near future, it makes sense to go into energy conservation/restoration mode and go to sleep.
Similarly, over the long term, if we aren't inspired by the life we see ahead of us, it's best to go into energy preservation and contemplation mode while we try to figure out how to get onto a better path (and if we can't find one, we end up in chronic/deep depression/despair).
I've overcome depression (and come off meds) by developing/learning techniques for finding optimism any time things seem bleak.