At least five tourists have died in Greece and others are missing as temperatures soar, according to media reports.

“Many tourists underestimate the effort associated with a walk in direct sunlight,” Athens cardiologist Thomas Giannoulis says.

“The temperature can rise to 37 degrees in the shade and easily up to 60 degrees in the sun.”

This increases the risk of dehydration and heatstroke.

“And the danger rises the older a person is,” Giannoulis says.

All of those who have died or gone missing are tourists aged from 55 to 80.

The first was a 67-year-old British TV presenter Michael Mosley, who went missing on the island of Symi and whose body was found on June 9.

Mosley had wandered off the path and collapsed at a spot where it was difficult for the search party to find him, the local authorities reported.

Two others died on Crete. An 80-year-old man who went for a walk on his own and a 70-year-old man who collapsed on a beach and died.

On Mathraki, a small island to the west of Corfu, a 55-year-old US citizen died while out walking. And on Samos off the Turkish coast, the body of a 74-year-old Dutch man was found days after he had gone for a walk on his own.

In the Cyclades, a US citizen has been missing on Amorgos for more than a week after he went for a walk. And two elderly French women are missing after going for a walk on Sikinos last week.

According to reports in the Greek press, some of the victims went out shortly after eating lunch and drinking alcohol. Others lacked a map or a smartphone or were in inaccessible terrain with no signal.