More active forms of yoga focus on physical postures, breathing, and muscle control, but yoga nidra guides practitioners into a state of conscious relaxation while they are in a lying down position. Practitioners report that the practice helps to improve sleep and cognitive abilities, but the reports were based more on subjective measures than on objective data. This study used objective polysomnographic measures of sleep as well as a battery of cognitive tests to investigate if the previous reports had merit.
The researchers described how in their study measurements were taken both before and after two weeks of yoga nidra practice, which were carried out during the daytime using 20 minutes of audio recordings. Among other tests, polysomnography measures brain activity were also taken to determine how long each sleep stage lasts and how frequently each stage occurs.
The researchers reported that after two weeks of yoga nidra, the participants exhibited a significant increase in sleep efficiency as well as a significant increase in the percentage of delta waves in deep sleep. The participants also displayed faster responses in all cognitive tests without loss in accuracy, as well as faster and more accurate responses in tasks inducing tests of working memory, abstraction, fear and anger recognition, spatial learning, and memory tasks.
The findings from this study are in support of findings from previous studies which link delta-wave sleep to improved sleep quality and better attention and memory. The researchers believe that this study provides objective evidence that yoga nidra is a low-cost, effective means of improving sleep quality and cognitive performance that is highly accessible which many people may benefit from.
“Yoga Nidra practice improves sleep and makes brain processing faster. Accuracy also increased, especially with learning and memory-related tasks,” wrote the researchers.
