alt Hacker NewsBurnout isn't about the number of hours. Burnout occurs because you are actively doing something that you fundamentally don't believe is worth the time.
I can work 80 hour weeks if it is a project that I am invested in or find interesting and feel zero burnout. I am working on a project currently I don't believe in and often I work maybe 6 to 10 hours of a 35 hour week and find it difficult to care about the work.
It's not as easy as that though; most people I know that ended up burnt out were the opposite, where they were actively doing everything that they fundamentally did believe was worth the time. Saying "yes" to every new responsibility, getting really enthousiastic and excited for every new opportunity, wanting to be involved and engaged with everything that comes in their path. Burnout starts (for these people) when they start to take work home, when they do extra in their free time, when they keep busy with work or something work related right up to the point where they go to bed.
This is where employers fail them. I get that employers actually want dedicated, committed, enthusiastic employees, and that these employers (and managers) do the same thing, taking their job home, living for the job, etc. But it's their job to protect their employees and themselves. If a manager finds out one of their employees is taking their job home, they should intervene.
But this is the double edged thing that managers - and lawmakers - have to deal with.