‘Slowly swallow a wet cloth which is four fingers wide and fifteen hands long in the manner instructed by one’s guru’, then ‘draw it out again’. Thus writes Brain Dana Akers in his English translation of the Hatha Yoga Pradipika. (Chapter two, Verse 24, if you really don’t want to take my word for it.)

At which point in my most recent yoga teacher training homework, I picked up a pen and (I don’t mind admitting) defaced – yes, defaced – a textbook. This from a woman who won’t even turn down the corners in a trashy paperback. I mean, what else was there to say but ‘WTF’?

And there was I, thinking Hatha Yoga was the ‘easy option’! No need to feel the burn, turn the thermostat up to stifling or balance on a single fingernail with your big toes wrapped round your neck.

Now I’m not so sure.

Seriously. Those medieval guys were hard core. Or nuts. You decide. Because there’s more.

Now we’ve flushed out ‘coughing, asthma, enlargement of the spleen, leprosy and twenty other phlegm diseases’ – or, rather more precisely, made them ‘vanish’ – we can busy ourselves assuming Utkatasana in water up to our navels.

Utkatasana, for the uninitiated, is Chair Pose, a standing posture which involves lowering the bum into a squat whilst pressing the feet and knees together, the toes still visible beneath the bent knees (perhaps not possible in waist-high water), and raising parallel arms, forwards and up, palms inwards.

It’s intention in modern yoga is to strengthen the legs and spine, stretch out the shoulders and chest, and stimulate the abdominal organs and heart.

Our medieval teachers, meanwhile, recommended the insertion of a tube into the <ahem> anus, before contracting it. The anus that is, not the tube, although I suspect the effect might be the same. That effect being that ‘all diseases arising from wind, bile and phlegm’ would ‘perish’.

Next up – and I bet you’re feeling better already, eh? – we must insert a very smooth thread nine inches long into our nasal passages before withdrawing it from our mouths, thus destroying the ‘flood of diseases originating above the collarbone’. An early version of the Neti nasal wash.

There’s explicit instructions about where to practise (secluded hut, ‘small door, no windows, no rat holes’), and questionable advice about eating a moderate diet of ‘satisfying, sweet food’ and avoiding anything ‘bitter, sour, spicy, salty or hot’, along with green leaves and alcohol (so that’s my ‘bad yogi’ tendencies dealt a crushing blow).

We must gaze at a tiny point with motionless eyes until our tears flow, revolve our stomachs with ‘the speed of a strong whirlpool’ and breathe rapidly in and out like the bellows of a blacksmith. Said to invigorate the brain and clear the sinuses, this latter practice of Kapalbhati breathing still features in many a yoga class. ‘Always have a tissue handy’ is my advice.

I’m a little disturbed that the practice of Gaja karani continues too in some quarters – thankfully not taught in any class I have ever attended. Described in the Pradipika as raising the ‘apana wind in the oesophagus to vomit the stomach’s contents’, it’s said by its modern followers to aid digestion, prevent heartburn, eliminate bloating and constipation, help reduce weight, cure diseases of the throat, clear the skin and generally raise your energy.

Deliberately and forcefully regurgitating the contents of the stomach through the application of two fingers in the throat is now called ‘tiger action’, because tigers ‘often overeat their prey, so after 3-4 hours regurgitate the remains of food from the stomach. This action allows not only to remove the effects of overeating, but also reduces the load on the intestine and the entire digestive tract’.

Oh dear me, yoga. No. As someone who spent their late-twenties and early thirties in the grip of bulimia nervosa, which involved purposeful overeating then doing just that on a daily basis, I wouldn’t recommend it. The tiger can do as it likes.

Giving it a Sanskrit name certainly lends an air of spiritual romance to what was, in the late 1970s and early ’80s, loosely termed an eating disorder (and largely swept under the kitchen table by the medical profession), but would now fall firmly under the heading of ‘mental health issues’. As for the many supposed health benefits, in my experience, the exact opposite to each is true.

Sticking two fingers down your throat throws up excess acid which burns your gullet, dissolves your tooth enamel and irritates your hearing to the point of tinnitus. It plays havoc with your digestive system, develops a tendency to irritable bowel syndrome and, when you’re still in the grips of it, renders you bone weary and means any meal, however tasty or lovingly prepared, is immediately followed by an urgent, purging trip to the loo to prevent it resting in your system long enough to ‘make you fat’.

Not the best way to express your appreciation of someone else’s efforts to nourish you, not to mention to nourish and care for yourself. It messes with your head, interferes with your relationships, and takes several years of expensive counselling and a lot of understanding from those who love you to get over. On the plus side, once you’re over it, you’ll never willingly overeat again, becoming possessed of an unfailingly efficient appestat.

But I digress. Back with the Pradipika. Someone should hand this book to Boris. Or Trump. Or whoever it is that’s advising them now. We’d have this coronavirus beat in no time. Forget the vaccine – wet cloths, nine inch threads and bottom tubes for everyone.

But I shouldn’t joke (not least because my teachers might be reading this).

There’s much to learn there too, once you accept that those were different times, without all the things we now take for granted in terms of sanitation, food, health (including the ability to identify, diagnose and treat illness) and the practice of yoga being free for all to enjoy, not just the select few – even women!

Hatha – from Ha (sun) and Tha (moon) – remains ‘the foundation for those practising every type of yoga’, its purpose to calm the body, mind and spirit in preparation for meditation.

And thanks to the Pradipika, I understand that yogic success isn’t achieved by ‘wearing the right clothes’ but by practice. (Farewell Betty. Bye bye Lulu. Farewell bum-sculpting pants and this season’s colours).

That when the breath is steady, the mind is steady. That through regular pranayama (breathing) and asana (posture) practice, we too become steady, better able to face the distractions and stresses of our lives, and the relentless pull of negativity.

That yoga builds physical strength and flexibility too, and helps keep us young in heart, body and mind. (Being liberated from old age, we’re told, ‘he will be a youth of sixteen’. To be honest, I’d settle for seeing fifty again).

Definitely worth getting out the mat for then. And infinitely better than chucking up tonight’s dinner. Trust me.