Are you referring to a situation where the workers are completely worn out because of all the extra time demands placed on them by these meetings etc.??

Thanks for your answer.

The direction should not be something like "worn out".
We just won't to say they do project work, meetings, business trips etc. and all of that leads to a 100 % of time. So, they are "ausgelastet".

...have a full work load
... are working at full capacity

Je nach Absicht des Sprechers.