Movement reminds the mind that being alive is not entirely an intellectual experience.

It is easy to live almost entirely in your head, and the cost is a slow loss of contact with the fact that you are a physical creature having a physical experience. Movement puts that back. It reconnects thought to breath and effort and sensation, and it usually lifts the mood in a way no argument with yourself achieves.

When your thinking has gone circular, change the input rather than the argument. Walk, lift something, go outside. The shift in state does what the reasoning could not.