Some cultivate asceticism, with fasting of one week, or three weeks; some fast as long as thirty-six days, and even up to seventy-two days.

有的修苦行打饿七，或二十一日禁食，或三十六日禁食，或七十二日禁食。

youdao

We found fifty people willing to move their accounts, forty-eight of them were very happy with the experience, seventy per cent of them completed the process within two weeks, and about half had completed it within one week.

BBC