Probably intentional weight loss. Most of the excavation work was done by women: https://en.m.wikipedia.org/wiki/Underground_Astronauts https://en.m.wikipedia.

Probably intentional weight loss. Most of the excavation work was done by women: https://en.m.wikipedia.org/wiki/Underground_Astronauts https://en.m.wikipedia.org/wiki/Underground_Astronauts