As he celebrated his 90th birthday last year, the man who brought yoga to the western world credited his healthy longevity entirely to his yoga practice. “Because I’m practicing,” said BKS Iyengar, “age has not struck me at all.”

The good news is that you don’t have to be a non-agenarian guru to reap the benefits of yoga - and it’s never too late to start. Of the 15.8 million people practicing in the US, almost three million are aged 55 or older and Ireland is hurrying to catch up, with classes for over 55s springing up all over the country.

Cork-based Julia Cotter has been teaching yoga for 30 years and celebrated her 70th birthday last year. These days, her morning classes are filled with students aged from their 40s up to 76.

“I teach gentle yoga,” she says. “I call it yoga for health. The theme I have is ‘easing the body to ease the mind’.”

Cotter is living proof of what yoga can do. “I had a mini stroke three years ago and I was able to work through it. I put that all down to yoga and tai chi,” she says. “I was lucky that it didn’t affect my speech or my limbs.”

Yoga can boost energy, increase flexibility and ease aches and pains, but today’s teachers are also discovering benefits for those with specific medical conditions, including chronic back pain, osteoarthritis and fibromyalgia. Cotter says yoga helps with “anything stress related”, listing depression, anxiety, asthma, weak back muscles, problems with the feet, digestion problems and insomnia. Regular practice can also lower blood pressure, blood sugar and cholesterol - all good news in the battle against heart disease, stroke and diabetes.

Cotter started out as a professional ballerina and now teaches sequences of postures and movements synchronised with the breath to release blocked energy. “It’s like central heating,” says Cotter. “If air gets trapped in the pipes, we have to release that blockage.”

A good yoga teacher will always include modifications to the postures to suit each individual’s needs and ensure that no one is left out. “There’s no competition in yoga,” says Cotter. “Each to their own capability… Yoga is gentle but very thorough and very safe provided people take responsibility for themselves.”

To this end, Cotter teaches each posture in three different stages, always working from the simplest version. “I compare it to your car,” she says. “You don’t start off in fourth gear.”

With yoga, people often start out looking to get fit and discover something more. “Yoga goes beyond muscles and joints,” says Cotter. “It’s gradual but, as people come deeper into their bodies, things start to change… Everybody needs yoga and you have it for life once you learn.”

Cotter is living proof of her own mantra: “To breathe is to be alive, and to breathe deeply and consciously is to live longer and stronger.” Amen to that.