Also don't forget:
Medieval peasants worked on average (depending on the area and era you are looking at) 30-60% less hours per year than present-day wage-workers
Medieval peasants who worked on someone else's land could elect not to go to work on any particular day and just not get paid for it (that's how weekends were created)
Medieval bosses (i.e. land-owners) were responsible for feeding their workers for the day with breakfast and lunch.
Usually lunch during field work was followed by a customary 2-3 hours nap.