Woman who was isolated from outside world to test biological rhythm?

Question

I read an article a few years back about a woman who had gone either underground, or was isolated from the outside world for several months to test the effect on the body.

She had no contact with the outside world, and could not see daylight.

Do you know who did this study?

Name of the woman, group, etc...?

Answer 1

Haven't found that particular one (yet), but I remember it. Link shows info about another one done around 1974:

"Seven solitary subjects, and two groups of four, spent from 5 to 13 days in an isolation unit without knowledge of time. Three solitary subjects and one group of four adopted fairly regular activity habits with a period of 25-27 h; one subject adopted a period of 30 h, and one of 27 h initially, decreasing to 24-25 h after a few days. One group of four awoke roughly every 24 h, after a sleep which was alternately about 8 h, or about 4 h and believed by the subjects to be an afternoon siesta. Two solitary subjects alternated sleeps of about 8 or 16 h, separated by 24 h of activity."