It seems with every passing year, a new and innovative spa trend is revealed, from bathing in beer to salt-iodine caves mimicking the effect of the Black Sea.
And the spa treatments tipped for 2013 look set to be just as inventive, from 'mindfulness massages' to vitamin C-infused showers.
An annual report has revealed how 'healthy hotels', wellness tourism and the holistic medicine system Ayurveda are expected to be among the top spa trends for the coming year.
The SpaFinder Wellness annual report, which was compiled by some 100 researchers who looked at trends, shows how the industry, which includes as many as 87,000 spas around the world, has shifted from beauty and pampering to health and wellness.
While gyms, pools and spas are standard at many hotels, it said that international chains and boutique hotels will be offering customized services such as in-room workouts, sleep programs, plus gluten-free and vegan menus.
'Hotels are realising that as people travel they want to stay healthy,' said SpaFinder Wellness Inc president Susie Ellis.
The InterContinental Hotels Group plans to open a wellness-focused brand hotel called EVEN in New York next year, with 100 more to follow within five years.
'It will be all about health and wellness,' Ellis said of the brand, which will revolve around fitness and includes quirky touches such as coat racks that morph into pull-up bars and a luggage rack that doubles as a workout bench.
Other U.S. hotel chains such as Westin are featuring guided jogs with running concierges and menus stocked with superfoods, according to the report.
Meanwhile, Las Vegas' MGM Grand has designed 'Stay Well' rooms with vitamin C-infused showers, wake-up light therapy, air purification and aromatherapy.
Jeremy McCarthy, the director of spa operations for Starwood Hotels and Resorts, said all of his hotels provide jogging routes and are starting to lend running gear to guests.
Along with healthy hotels, the report predicts an increased demand for authentic Ayurveda, the 3,500 year-old Indian holistic system of medicine, and other ancient treatments.
The study also tipped rather more complex treatments such as 'earthing', a process which 'grounds' the body to the earth's surface and 'stabilises natural electrical rhythms and reduces disease-causing inflammation' and 'Spa-Genomics', which relies on DNA information to create a personalised treatment.
'Look for more authentic Roman and Turkish baths, Russian banyas (steam rooms), traditional Chinese medicine and Nordic offerings,' the research added.
More men have been going to spas for several years, and that is expected to continue in 2013, the research noted.
In addition to massages, more men are seeking a manicure and pedicure, facials, fillers and so-called 'brotox.'
The trend is fueled by aging baby boomers wanting to hold on to their looks and younger men who are comfortable with the concept of male beauty.
'It's not just more culturally acceptable for men to spend on looking good, it's becoming perceived as a necessity,' the report said.
'Even territory once heavily reserved for women, like bikini waxing, is now being invaded by males.'
Ellis predicted a surge of people traveling abroad to stay healthy. The report cited India, which has seen a 22 per cent annual growth in wellness tourism, as a prime example.
'Travelling for prevention and improving health is going to be huge,' she added.