I have personal experience of working this hard, but having never been depressed I have never had to use this approach. I have worked with people who have used it successfully and if I were to get depressed it is exactly what I would do.
It seems to be important that it is both hard physical labor and outdoors in the sun.
I do, and it works great! I normally work a desk job, alternating between the two is amazing. Working that hard every day of the year isn't sustainable, but physical labor in shorts bursts of a week or so can boost my mood for months.
It seems to be important that it is both hard physical labor and outdoors in the sun.