Movement is powerful. Being in one place for long kills us. A weak body won't support a strong mind.
As CGP Grey outlined in his Spaceship Productivity video a few months ago, physical health is something that can, and often does, bring up our mental health from the lowest points.
Our bodies have been made for movement. That's how we optimally exist, how the engine inside of us can function. While food is the fuel, an engine won't work if its just sitting full of fuel. It needs to be used, to burn that fuel from time to time. If that doesn't happen, it becomes useless.
Sitting, especially sitting, is so bad. It's worse than standing or laying down. Yet it's what our environment is designed for. Think of the car, the desk, the sofa. Sitting and stuffing ourselves. That's the worst thing one can do.
Move, keep the fire burning, the engine running.
Unless you want to put it out faster.