I certainly haven't done a study, no. I'd love to see one too.
I believe there has been some evidence that supports the ~40 hour work week. I suppose 40 exactly is a tad arbitrary, optimal number is probably some strange decimal, but I'd be surprised if it wasn't really close to 40 for the average person.
Perhaps it depends on the individual, perhaps for some its 40 and for some its 50, etc. Maybe the latter group succeeds more. I feel like this is untrue, but certainly can't prove it.
I believe there has been some evidence that supports the ~40 hour work week. I suppose 40 exactly is a tad arbitrary, optimal number is probably some strange decimal, but I'd be surprised if it wasn't really close to 40 for the average person.
Perhaps it depends on the individual, perhaps for some its 40 and for some its 50, etc. Maybe the latter group succeeds more. I feel like this is untrue, but certainly can't prove it.