I love my yoga teacher, but every week in her class – at about the 10-minute mark – I have to practise selective hearing. That’s around the time we sink from plank into baby cobra as part of our sun salutations, and the part when she tells the class that by lowering our chests to the mat, we’re “resetting our endocrine system”. From my spot on the floor, I’m focused on resetting my eyeballs from where they’ve rolled to the back of my head.

I’m definitely not the first person to have heard such piffle in a yoga class, and online, the incense-hazy nonsense is equally ubiquitous. All it takes is a cursory scroll through your social media accounts or a quick Google search to reveal that a number of yoga practitioners are seriously reaching. I even found one reel promising to cure sinusitis through regular salutations (a condition that the NHS recommends seeking medical attention for if it doesn’t get better on its own and for which steroids may be necessary). I’ve come across e-books by people who claim that yoga reversed their incurable diseases and articles promising to reverse hypothyroidism in eight poses or manage hormonal imbalances in five.  

Dr Anu Kumar is a GP with over 20 years of experience who started practising yoga in 1997 and qualified as a yoga teacher in 2016. She has heard plenty of misleading claims herself as a yoga student, including one teacher who claimed that osteoporosis of the spine was caused by not doing enough ‘heart-opening’ exercises. “I did talk to a few of the other students about it,” she says, “but it absolutely took me out of the moment because what I heard was completely factually incorrect.”

She says she’s also heard teachers claim that particular poses stimulate the thyroid or pineal gland: “It’s misleading and unevidenced. It makes me question the yoga teacher.”

But some other of the more ‘out there’ claims about yoga are well-evidenced: “The neuro-endocrine system is positively affected by exercise and breathwork. Blood flow through organs is generally a good thing, but that’s something yoga has in common with all exercise. Breathwork can damp down the sympathetic nervous system, and emerging research on stretch receptors and SARS receptors at the bottom of the lungs suggests it can have a positive effect on stress hormones.”

The thing you definitely don’t need to pay attention to is any chat about the pineal gland. “It is almost an extinct gland in the brain,” Dr Kumar explains. “Doctors don’t test or measure the pineal gland as much as we do other glands, such as the pituitary, pancreas or adrenals.” 

Nadyne McKie teaches yoga within the NHS and is also a BACP-accredited therapist. She too has her own anecdotes about yoga class waffle.

“Funnily enough, in a class last weekend I heard somebody say: ‘If you put your forehead on your knee and compress the neck and throat area, you can influence your thyroid function,’” she says. “There’s just no direct scientific evidence of that. The thyroid gland is regulated by the pituitary gland through the release of hormones; it’s very, very complex. To suggest that we can influence that by mechanical pressure or stretching is misleading.” She says when she hears comments like that, it often stops her going back to a class.

McKie is also concerned about making sure yoga clients with specific conditions are safely supported in classes. “I’ve heard very recently that some teachers work with conditions like postural orthostatic tachycardia syndrome (PoTS) when they’re totally unqualified to do that. They could put somebody into a state where their heart rate rises rapidly, and that’s going to be scary for them. Teachers staying in their competency area is super important.”

The power of yoga, she believes, lies in its ability to reduce stress and its impact on the body. “Yoga as a holistic practice. Integrating slow breathing and creating awareness of our bodies can increase our ability to downregulate the nervous system,” she says. “This is really well evidenced. It decreases the stress response in the body, and that could influence the regulation of hormones related to things such as our immune response, metabolism, reproduction, growth, and all those kinds of things.

“Stress is our main disruptor of the endocrine system, so a regular yoga practice encouraging slow, nasal, diaphragmatic breathing, meditation and mindful movement can help us to regulate functions such as blood pressure and reduce stress hormones (cortisol and adrenaline), which helps us feel more calm.”

Likewise, Dr Kumar says that teachers shouldn’t be making claims that certain poses stimulate the thyroid. “Using a medical term like ‘thyroid-stimulating’ in yoga is completely inappropriate. I’m not sure something like hanging upside down is going to get more blood to the thyroid gland. Obviously, any kind of practice that is going to energise the endothelium (a thin layer of cells that lines the blood vessels) and get blood flowing is great, but the term ‘thyroid-stimulating’ is not a good term to use about poses because of the pathophysiology of the way the thyroid gland works.”

Both McKie and Dr Kumar emphasise that specific poses don’t have special functions or powers. “To say that there’s any specific pose that can, for example, reset your endocrine system, I think is misleading,” says McKie. 

Finally, Dr Kumar points out that the class that the gym lists as ‘yoga’ – the asanas, or poses – is only one of the eight parts of the classical practice of yoga. Some teachers may be too quick to use medicalised explanations in yoga classes rather than looking at the spiritual meanings, she says. “When you’re talking about detoxing, for example, you could say that meditation is a cleansing practice (kriya). It’s not getting rid of toxins from the body but it’s getting rid of something that might have been causing you harm.”

On reflection, perhaps instead of ‘resetting my endocrine system’, that yoga practice actually reset my creativity so I could pitch and write this article. As long as my yoga teacher’s not trying to open my pineal gland, I think I’ll stick with her.  

Images: Getty