At least in terms of a regular work routine. In times of crisis, working long hours is completely reasonable.

Work too hard and you also lose sight of the bigger picture. Research has suggested that as we burn out, we have a greater tendency to get lost in the weeds.

In sum, the story of overwork is literally a story of diminishing returns: keep overworking, and you’ll progressively work more stupidly on tasks that are increasingly meaningless.

https://hbr.org/2015/08/the-research-is-clear-long-hours-backfire-for-people-and-for-companies