The death of former navy Seal diver supplying oxygen to the teams tending to the 12 boys and their football coach trapped in a flooded Thai cave system has shown how dangerous any rescue attempt could be.

Petty Officer Saman Gunan lost consciousness on his way out of the Tham Luang cave complex, where he had been delivering air tanks.

The boys have already spent almost a-week-a-half underground and and their situation already poses several health risks to them, academics have warned.

The psychological stress of initially being lost and the subsequent uncertainty around their rescue, is likely to be taking a serious toll on the group in the short term, according to Dr Andrea Danese, head of the Stress and Development Lab at King's College London.

“They may become fearful, clingy, or jumpy,” she said. “They may be fear for their safety; become very moody or easily upset – or, in contrast, become detached or numb – or they may develop headache and stomach-ache related to the intense distress.”

While most of these will be temporary and alleviate within a few weeks of their rescue, Dr Danese warns that in some children, the traumatic experience could have a lasting effect.

“We can expect that a sizeable proportion of the young people involved – 10 to 20 per cent – will develop more enduring mental health problems related to the trauma, such as post-traumatic stress disorder (PTSD), depression, or conduct problems,” she added.

Even with rescuers now bringing in food and drink to help build up the boys’ strength, there could well be physical health consequences from being trapped underground.

Care packages dropped for boys missing in Thailand cave

Most critically, the oxygen supplies in the cave where the group is located are dropping. This has led to media reports citing Belgian divers working with the rescue suggesting a rescue attempt is imminent.

Previously one option being considered had been whether the boys could wait for an end of the rainy season when the water in flooded sections of the tunnel would subside.

“The lack of daylight over this period of time means that they may not only be psychologically disoriented, but that many of their basic physiological functions that depend upon circadian rhythms will be disturbed, said Sarb Johal, an associate professor at the Joint Centre for Disaster Research at Massey University in New Zealand.

These circadian rhythms are also how our body knows to wake and go to sleep, and causes our metabolism to slow down at night.

It also plays a role in various other bodily processes, including the levels of hormones which can affect stress, switching body temperature up and down and affecting food’s digestion.

Though it’s unlikely to be practical in an urgent rescue situation, Dr Johal said lighting which follows the day-night pattern of the outside world “may help to regularise some of these bodily functions” – particularly if they will be living there for an extended period.

Infection could also be an issue in the cave.