[karambahh]

As mentionned elsewhere, 30h of being "in the zone" is already above average.

Above that, the teams will be present, or rather their bodies will be, but non productive.

Death march is a real thing and it results, as the name implies, in death.

As a manager, if you choose to run your team in death march mode, then it implies reaching your goal is more important than the well-being of your team and the ability to function long-term. Short term is... short term.