Two weeks of 20-minute yoga nidra sessions led to a higher percentage of delta-waves in deep sleep and better memory, decision-making, and abstraction

Practicing yoga nidra—a kind of mindfulness training— might improve sleep, cognition, learning, and memory, even in novices, according to a pilot study publishing in the open-access journal PLOS ONE on December 13 by Karuna Datta of the Armed Forces Medical College in India, and colleagues. After a two-week intervention with a cohort of novice practitioners, the researchers found that the percentage of delta-waves in deep sleep increased and that all tested cognitive abilities improved.

Unlike more active forms of yoga, which focus on physical postures, breathing, and muscle control, yoga nidra guides people into a state of conscious relaxation while they are lying down. While it has reported to improve sleep and cognitive ability, those reports were based more on subjective measures than on objective data. The new study used objective polysomnographic measures of sleep and a battery of cognitive tests. Measurements were taken before and after two weeks of yoga nidra practice, which was carried out during the daytime using a 20 minute audio recording. 

Among other things, polysomnography measures brain activity to determine how long each sleep stage lasts and how frequently each stage occurs. After two weeks of yoga nidra, the researchers observed that participants exhibited a significantly increased sleep efficiency and percentage of delta-waves in deep sleep. They also saw faster responses in all cognitive tests with no loss in accuracy and faster and more accurate responses in tasks including tests of working memory, abstraction, fear and anger recognition, and spatial learning and memory tasks. The findings support previous studies which link delta-wave sleep to improved sleep quality as well as better attention and memory.

The authors believe their study provides objective evidence that yoga nidra is an effective means of improving sleep quality and cognitive performance. Yoga nidra is a low-cost and highly accessible activity from which many people might therefore benefit. 

The authors add: “Yoga nidra practice improves sleep and makes brain processing faster. Accuracy also increased, especially with learning and memory related tasks.”