What is yoga nidra?

Brought to the masses in the early 1950s by Swami Satyananda Saraswati, yoga nidra has its roots in ancient tantric texts. The practice claims to help you reach ‘the border between waking and sleeping states’. Sometimes described as ‘dynamic sleep’, it allows the body to get into a deep state of relaxation, while keeping the mind alert.

What’s involved?

In a class, you will be asked to lie on your back with your arms at your sides, palms up, eyes closed, usually covered in a blanket so you’re warm and comfortable. The yoga teacher will ask you to set an intention for the class, then they’ll move through a ‘tour’ of your body (right big toe, right little toe, top of the foot, heel…). You’re encouraged to focus on your breath as they guide you through visualisations and affirmations before returning you to wakefulness. Through the process, you’ll become steadily less aware of the world around you, and will instead draw your attention inwards. The teacher’s voice may feel far away, and it may be difficult not to fall asleep, but you should emerge feeling relaxed.

What are the benefits?

After a 30-minute session, you should feel like you’ve had the equivalent of two hours’ sleep; refreshed, centred, and calm. Yoga nidra benefits are believed to include regulating hormones, stabilising glucose levels, and easing depression, anxiety and even post-traumatic stress disorder (PTSD), because the deep relaxation of the nervous system helps it recover.

Normally, when you fall asleep, your brainwaves move from active beta waves into a thoughtless state of alpha waves, before they pass into the slowest frequency of deep sleep, called delta waves. Yoga nidra puts you in a ‘hypnagogic state’, which is the threshold between alpha and theta waves, or the ‘moment’ where the body is sleeping while your mind is lucid. Powerful stuff.

Any science behind it?

A surprising amount, although sample sizes have been small. Two papers have found that yoga nidra improves blood pressure, heart rate and hormone irregularities. Another compared type 2 diabetes patients who were either given just medication, or medication plus yoga nidra sessions, and the yogis saw fewer fluctuations in blood glucose levels.

In 2006, US researchers tried out the technique on soldiers returning from Iraq and Afghanistan with PTSD. It was so successful that yoga nidra became a weekly treatment program for soldiers. Danish researchers have performed brain scans on people as they practice yoga nidra, and proven that theta activity rose significantly, but the reduction of alpha activity was insignificant – evidence that meditation puts you in the ‘fourth major state’, equal to dreaming, sleeping and wakefulness. College students who used iRest yoga nidra for 90 minutes a week for eight weeks saw significant drops in perceived stress, worry and depression, and when weekly iRest sessions were given to veterans, those involved reported reduced rage and anxiety. Among patients with menstrual irregularities, a yoga nidra program provided stress relief, lowering anxiety and increasing positive wellbeing, general health and vitality.

Read more: 5 types of yoga and their benefits explained