They say that life is not a sprint.
That it is a marathon.
I'd say if we're making analogies then at least let us not break down the act of living to something so unidimensional as getting from start to finish as fast as possible. A sprint that ends sooner is a better sprint. Can the same be said about life? So let's demand a little more from our analogies, i.e. that they don't fall apart at the first test.
Life is more like a trek.
You see, neither the sprint nor the marathon go any place meaningful. But treks do. Reaching the end of one trek has a different meaning than reaching the end of another. All sprints are equally meaningless. All that is interesting about them is that they cover a particular distance. I don't like to look at my life as a task to be completed as quickly as possible.
A trek involves reaching higher, reaching places from where one can see further, from where one's horizon is expanded. Treks involve beauty, and the stop to admire the beauty. To live for a while humbled by the beauty of creation, to give thanks for this vessel your body through which we experience this world and to feel closer to the Creator. I like to think my life can be like a trek.
And there is no trek that goes anywhere meaningful that does not include rest as a part of the trek.
Rest is absolutely crucial to pushing through to the end of the trek. For reaching summits that are beyond one's capability, where it takes an absolute will to succeed and every last bit of sinew, there is no getting there without careful preparation and an optimal usage of all one's resources and strength. And such optimal use is impossible without rest.
If you want to further than you think you can go, you're going to have to use your energy strategically. And hustling 24/7 is the very opposite of strategic use of energy. It might work over shorter time durations, but for those of us who want to play the long game, periodic rest is very important.