As a general rule, writing less rather than more is a wise decision.
And when you are tired, writing less rather than more should be an imperative. When you are tired, ideas gets fuzzy, reasoning falters, words get mixed up. Adding another sentence, another paragraph, another page will not make your argument stronger.
Of course, it is also possible to not write at all. Go get some rest, and get back to what seems the most urgent matter of the moment when it does not seem as urgent anymore (a night of sleep has this power).
Businesses would benefit immensely from this practice.