By taking an action (any action) we mobilise our body to mobilse our mind. Alternatively, the more we do the more we want to do. The Seligman’s dogs would not learn to tolerate the state of pain, if they jumped over the fence. However, they could not command themselves to do so. But we, humans, can slightly impose our will on ourselves, even if we do not feel like.
Lets say we are in our room surrounded by negative thoughts. We may believe/think that our life is miserable, that we are worthless and so on. By literally garbing ourselves and making a move -anything, e.g. having a walk- we put ourselves in another mode. Perhaps our thoughts will not turn to positive. They will just might be less negative, or equally negative but simply different. However, WE did that, by our own actions. WE interrupted this pattern of helpless thoughts. And that is a win that our mind consciously or unconsciously registers with its pros.
By doing so in the long term we allow no space for helplessness. And the better we feel now the higher we place ourselves for our next step. No second to be lost like this; at least when the blood still runs through our veins.