Well, if some sort of artificial gravity is not implemented:

"The level of gravity on the moon—about 17 percent that of Earth’s—could wreak havoc on bones, muscles, and other organs. And then there are the psychological aspects of what one NASA astronaut described as the “vast loneliness” of the moon."

source: https://spectrum.ieee.org/moondust-radiation-and-low-gravity-the-health-risks-of-living-on-the-moon