Mindfulness is selling millions of books and apps, it appears on the front cover of Time magazine, pops up in the Financial Times and is used by all kinds of people from corporate executives and nurses to sportsmen and primary school children. Once a poorly understood New Age fad, it has moved from the margins to the mainstream. Nothing demonstrates that better than the launch of an all-party parliamentary group on mindfulness on Wednesday.

At this point I will come clean. I am one of a group of people working with three universities (Oxford, Exeter and Bangor) to support the all-party group. What interests us – academics, journalists, mindfulness teachers – is the potential for public policy. What role could mindfulness play in schools, in the NHS or in the criminal justice system?

But let's start with definitions, which are notoriously difficult with this phenomenon. What exactly is mindfulness? Because it has precious little to do with the pretty women sitting on beaches with their eyes closed who are usually used to illustrate articles on the subject. The only way to explain is to suggest you try. Right now. Close your eyes and bring your attention into your body, to the sensation of your feet on the ground; the movements of your breath, the expansion of your rib cage. Stay with these tiny physical sensations. Patiently. Without getting cross with yourself for getting distracted. Try it for two minutes.

Unfamiliar? It is, because our minds spin with thought, and we are absent to much of our physical experience. But bringing the attention back to the most basic and essential part of living – the breath – we can slowly bring an awareness of the obsessive thought patterns and the instant reactions which on reflection we so often realise were unhelpful or even destructive.

Mindfulness is both astonishingly simple and, for most of us who live in our heads, very difficult. It is also immensely rewarding, as plenty of people are discovering. I would argue that it is probably the most important life skill I am learning (after 15 years of practice, I am acutely aware that there is always more to learn). It is up there with reading, and probably in my old age with eyesight gone, it will prove more valuable to me than books.

The interesting thing about mindfulness is that it would probably have stayed on the margins – a passion for only a few – if it hadn't been taken up by scientists as a subject for research 40 years ago. It started with an American scientist, Jon Kabat-Zinn, who began to research its value in dealing with chronic pain. It is now widely used in hospitals all over the world.

An international team, including Mark Williams, a psychologist at the University of Oxford, then led research trials into mindfulness as a treatment for recurrent depression. Their success led to the National Institute of Clinical Excellence recommending it as a treatment. There are now passionate advocates within the NHS running projects around the country.

But increasingly, academics such as Willem Kuyken, a psychologist at Exeter University, are asking whether, if mindfulness can work for depression and pain, anyone else might benefit? What role could it play in schools, and could it help our national epidemic of mental ill health in adolescents?

The analogy that Kabat-Zinn uses is with jogging. In the 1960s when he started running, people thought him a bit odd. Now on a Sunday morning parks and streets are full of people pounding away. The take-up rate for mindfulness, Kabat-Zinn says, is much sharper than for jogging. In another decade, one can imagine that it will be widely accepted and understood as a valuable way to look after your mental health. Just as physical exercise is vital to a desk-bound workforce, so mindfulness will come to be seen as vital for dealing with the complexity of our information-rich lives.

What mindfulness slowly brings to our understanding is how much our experience is shaped by our minds. To have that insight as a personal experience rather than something one reads in the growing body of scientific literature on the subject is transformational. It loosens that reactivity which can trap us in a limiting loop, and allows for very different responses which can manifest in all kinds of ways – greater creativity, more empathy, more patience, less judgment.

Some call this a mindfulness revolution but, like Jonathan Rowson at the Royal Society of Arts in a recent thoughtful blog, I think the jury is still out. Mindfulness is derived from Buddhist meditation, which at its heart is revolutionary in its emphasis on compassion and non-harm. It is profoundly counter-cultural in its asceticism. But this derivative has been meticulously framed as secular by a generation of scientists.

They identified that the Buddha's insights into the behaviour of the human mind was resonating with breakthroughs in psychology and neuroscience. Delinked from Buddhist ethics, mindfulness could become a form of performance enhancement – some of the enthusiasm coming from the corporate sectors and military leads it dangerously in this direction. That is a real risk. As is the danger of a sort of wild west of unregulated teachers, which any cursory web search reveals is well under way.

Another risk is that it becomes the privilege of the stressed middle classes who can afford the courses. Some of the most inspiring work is being done by people like Gary Heads in County Durham who is working with unemployed people. Or the project in Cardiff which taught the single mum who recently stood in front of a gathering of Welsh Assembly members to describe movingly how mindfulness had helped her to be a better parent, as well as to find the confidence for public speaking.

The point is that, diligently practised, it very quietly and slowly revolutionises lives in multiple ways – sometimes small, sometimes big. And when you start noticing that process of change – both in yourself and in others – it is quite simply astonishing.