Hi,
I am not trying to knick-pick anyone's writing but I think Cool Breeze used the word 'action' without the article like this.
More seriously, while is often used to refer to long-lasing action.
I look up my Collins Cobuild Advanced Learner's English Dictionary and it noted like this among many otheres:
Action is doing something for a particular purpose
An action is something that you do on a particular ocassion.
How do we know which one is being used? Do you have any tips?