NASA could send a control group of astronauts to space with NO duties and see if it has any effect on health (relative to those with “jobs”). Space travel is surely stressful, but perhaps the additional pressure of having tight schedules and deliverables is an additional stress?
Absence of duties, schedules and deliverables can be quite a stress factor as well. I would not be surprised if that control group would end up suffering even more from being locked up in a free-falling can.
