I should note that I often spend my days working construction and regularly average 3 hours of exercise per day. Doesn't help me that much. Big exception made for the first day spent surfing if I haven't surfed in a while, that knocks me out cold.
It makes sense to me that if we stimulate ourselves through sugar, caffeine, artificial light, information, worry etc that we can benefit from a mild depressive to balance the stimulus. The other option is a monk-like existence that I haven't been able to keep going for more than a few months at a time and wouldn't want to go back to.
It’s doubtful to me that pre-industrial folks had a ton of trouble going and staying to sleep.
And fwiw, “working out” helps, but isn’t the same as a day’s manual labor.