Scientists from the US space agency NASA have advised the trapped Chilean miners to regulate their day and night sleep patterns.
A team of four visiting experts said the men should boost their Vitamin D intake and phase in an exercise programme as their nutrition improves.
The 33 miners have been in a tunnel 700 metres below the ground since a rock fall on 5 August.
They must now wait two to four months for an escape shaft to be drilled.
The BBC reports Chile's government invited the NASA team to the San Jose gold and copper mine to offer tips for helping the men keep physically and mentally healthy while they wait to be rescued.
"One of the things that's being recommended is that there be one place, a community area, which is always lighted," said Al Holland, a NASA psychologist at the mine.
"And then you have a second area which is always dark for sleep, and then you have a third area which is work, doing the mining, and the shifts can migrate through these geographic locations within the mine and, in that way, regulate the daylight cycle of the shift."
The miners lost an estimated 10kg each during the 17 days before they were found alive. Since then, they have been receiving food, water and medicine through three bore-holes.
On Thursday, the men received their first hot meal - meatballs, chicken and rice. Previously they had received only glucose tablets and high-protein milk.
NASA team leader Michael Duncan said an exercise regime should be added to the miners' schedules.
"Before our astronauts go into space, we put them on exercise programs and the miners, even though they're doing some work down there, we will want to phase in some exercise programmes as their nutrition improves," he said.
Rescue shift
Drilling of a rescue shaft at the mine, near Copiapo, has penetrated more than 40 metres deep since it began on Monday.
A second, faster drill that could aid the men's rescue arrived at the site on Friday and could begin work on Sunday.
The T-130 excavator will be deployed initially to enlarge the supply chute to allow larger objects to be sent down to the 33 men.
