Yip, I totally agree that it's like exercise, and I totally totally agree that you should start slowly.
However! where I did it (in New Zealand) vipassana specifically started you at the 10 day course (or did 8 years ago), there was no option to do a shorter one. Or if there was, they certainly didn't stop you jumping straight into a 10 day.
Good point. If I have to make an analogy it seems like putting a person not physically suited for the military into a strict military 10-day brutal survival bootcamp. They need to be more careful with this indeed.
However! where I did it (in New Zealand) vipassana specifically started you at the 10 day course (or did 8 years ago), there was no option to do a shorter one. Or if there was, they certainly didn't stop you jumping straight into a 10 day.