THERMOPYLAE, Greece (AFP) ― Hercules used them to regain his strength after his legendary labors, Hippocrates lauded their beneficial properties and even a famous Roman general, Sulla, said he owed his health to them.

Their praise was for hot springs, a medicinal resource known and appreciated in Greece since antiquity ― though regrettably less so nowadays.

“Greece invented the therapeutic use of hot springs thousands of years before the birth of Jesus Christ,” says Zisis Aggelidis, a professor of hydrogeology at Thessaloniki’s Aristotelio University.

In ancient Greece, healing temples known as Asclepieia ― named after the god of medicine Asclepius ― were popular with pilgrims.

Greece today has some 700 hot springs known to have curative properties, but just over 100 are accessible and even fewer are commercially exploited.

Many are still free of charge to the public, out in nature with minimal facilities, even on popular tourist islands such as Santorini, Milos and Kos.

Evangelos Kyriazis, a barrel-chested man in his 60s, says he has not been to a doctor in years thanks to his local spa.

Kyriazis’ magic potion bubbles forth from a mountain in central Greece, near the town of Thermopylae.

His self-styled treatment is to take 300 baths a year for half an hour in the sulfurous water, which has a temperature of between 30 and 40 degrees Celsius.

“It detoxifies and oxygenates the body, regulates pressure, dilates the blood vessels, relaxes the muscles, clears the lungs, strengthens the bones and relaxes the nervous system,” says Kyriazis.

“It even whitens the teeth.”

Thermopylae, literally “hot gates” in Greek, has become synonymous with the ferocious battle in which 300 Spartans sacrificed themselves against overwhelming Persian odds in B.C. 480.

Few today, however, associate Thermopylae with the hot springs Hercules frequented in Greek mythology, except a few locals and a small number of connoisseurs.

“These springs cured my aching knees and shoulder. The waters here are more natural than in Germany,” says pensioner Alfred Weigel, who makes an annual pilgrimage from his native Bavaria for a dip here.

To the uninitiated, the site appears inauspicious, close to an abandoned petrol station and a derelict hotel. Bathers change in their car, and step over a wobbly wooden pallet to reach the springs.

“We have an exceptional product but it is poorly used,” sighs Markos Danas, secretary general of the union of Greek spa towns.

He notes that across the country fewer than a dozen sites offer acceptable tourism infrastructure.

“Hot springs are mostly run by local communities, and this has limited the scope of development,” he adds.

Three of Greece’s best-known spa towns are Loutraki in the Peloponnese, Kamena Vourla in central Greece and Edipsos on the island of Evia.

The latter is known to posterity through the Greek biographer Plutarch as the site that cured Rome’s Sulla.

For years much of the clientele were Greek pensioners on state-funded curative tours.

However, in the wake of the economic crisis gripping the country for the past five years, demand has fallen dramatically.

The union of spa towns reports a 50 percent drop in paying customers since 2009.

The spa towns are now hoping an EU directive that authorizes reimbursing citizens for taking hot baths in other member states will revive interest.

Greece’s state privatization agency last year also offered four hot springs in central Greece, including Thermopylae, for sale to private developers.

But there were no takers ― meaning more free visits for Evangelos and his fellow bathers in the foreseeable future.