Chilean officials organizing the rescue of 33 trapped miners say some of the miners may have to lose weight to fit through the rescue shaft being dug.
Health officials are preparing exercise programs to keep the trapped miners fit and help maintain their mental well-being. Engineers are working to drill a 62-centimeter-wide rescue tunnel, but they say it could take up to four months to complete because of the depth and instability of the mine.
The miners are trapped 700 meters underground.
Rescue workers have asked the U.S. space agency for advice in maintaining the physical and mental health of the miners. NASA has experience testing and training astronauts for extended periods of isolation.
Submarine crews from Chile's navy are also being consulted.
Two narrow holes have been drilled to communicate with the miners and deliver food and other supplies to them, including games and even anti-depressants.
The miners have also used the holes to send messages to loved ones.
In a demonstration of stoicism and resolve, the trapped miners sang Chile's national anthem after communications were established with the surface.
The miners became trapped three weeks ago when a shaft collapsed in a gold and copper mine near the northern city of Copiapo. They have told officials they are fine. Rescuers first made contact with the men on Sunday.
Officials say the miners appear to have organized themselves well and have rallied behind their shift supervisor.