Salt caves are enjoyed around the world, providing beautiful places to relax
The tiny white crystals covering the walls sparkle like ice, while the thick layer of soft grains beneath my feet resemble a pristine blanket of snow.
The comfortable loungers, soft lighting and relaxing music make it easy to see why salt cave therapy can make for an enjoyable experience but what's really appealing is the positive effect it can have on asthma, a condition that affects 5.4 million people in the UK.
Having suffered with mild asthma since childhood I'm keen to see if breathing in salt can help improve my symptoms.
Asthma occurs when the airways of the lungs become inflamed and narrow causing coughing, shortness of breath and a feeling of tightness in the chest.
Known to run in families, common triggers include allergies to dust mites, animal fur and pollen.
However, around 40 per cent of adults find theirs is caused by a non-allergic trigger such as exercise, having a virus or in my case the cold weather.
The positive effects of salt on airways were first noted in Eastern Europe in 1843 when a Polish doctor documented how salt mine workers didn't seem to suffer from the same respiratory problems as the general population.
The theory is that salt helps reduce inflammation and mucus.
Among the 20,000 people who have visited salt cave facilities in the UK many are asthma sufferers, have sinus problems, cystic fibrosis or lung damage.
Sofia Benke, co-founder of The Salt Cave which has five branches in the UK, says: "You inhale tiny particles of salt which are small enough to penetrate deeply into the lungs. The salt loosens the mucus making it watery and also helps to reduce the inflammation making more room in the airways for you to breathe.
"One of the first things people notice is their nose runs and they cough. This is the body clearing the mucus."
Dr Adel Mansur, a consultant physician specialising in asthma at the Birmingham Chest Clinic and Heartlands Hospital, adds: "We know that salt can help people to clear their chests. In hospital we use a treatment based on the inhalation of a moist, salty solution which helps to break down and clear the sticky mucus within the airways which causes irritation."
Salt therapy is so popular in Poland and Russia that people go to natural salt caves for as long as a week, even staying in underground hotels within the caves.
I head to London's manmade The Salt Cave which was opened by Sofia and her husband Denes Gal in 2009.
The couple imported hundreds of tonnes of salt from the Red Sea (known for its purity) and compacted it to create the cave's walls.
With one in 11 children suffering from asthma there's even a mini salt cave just for them.
I'm allowed to wear my own clothes but users have to cover their shoes or go barefoot.
On entering the cave at the start of my one hour session the first thing I notice is the air feels clean and crisp. It's also warmer than I imagined.
The therapy is delivered by a specially designed machine which grinds and pumps salt into the cave and the levels can be adjusted according to need. You can hardly see the salt.
It's like a very fine mist, a hint of which you can taste at the back of your throat.
The cave can hold up to 10 people and asthma sufferer Marissa Godden, 45, from London is a convert.
She first tried salt cave therapy when her asthma spiralled out of control forcing her to give up full-time work.
"I was wheezing and coughing so much I could hardly walk a short distance and my chest was very sore," she says.
"Someone suggested the salt cave and I thought I'd give it a go."
After two sessions her sinuses started to clear and she could breathe through her nose again.
By the fourth session her chest felt less tight and painful and her breathing began to improve.
After 20 sessions Marissa's improvement was evident in a peak flow meter which measures airflow out of the lungs.
I was wheezing and coughing so much I could hardly walk a short distance and my chest was very sore
Marissa's reading had been a very low 200-250l/min (litres per minute). After her course of treatment her airways were much clearer and her level rose to 300l/min which is closer to a normal reading of between 400 to 600l/min.
"It has made an enormous difference," says Marissa. "My lungs feel clear, my cough has gone and there is no pain.
"I'm able to look for full-time work again and go back to exercising."
Like Marissa people typically need a course of 15 to 20 sessions although many go at times of the year when their breathing is most problematic.
Dr Mansur also believes that there is a benefit beyond the medical evidence.
"Stress, anxiety and panic are closely connected with the triggers of asthma for many people. If there is a treatment which helps them to feel better and have more control over their breathing, that has an important benefit in itself."
After my session I wondered what sort of effect it might have.
As Sofia predicted I did need to blow my nose more often and that evening my irritating tickly cough had gone.
I am intrigued and will certainly return to the salt cave.