The brain in deep sleep and samadhi have a lot in common. Physiologically, both states are associated with a decrease in heart rate and breathing rate. Research has shown that regular meditation can cause changes in the body that are similar to those that occur during sleep. This restful alertness that is experienced during meditation is linked to a decrease in heart rate, reduced metabolism, and changes in the nervous system that reduce the arousal that happens during sleep.
Studies have suggested that meditation can replace sleep. Instead of trying to fit it into your daily routine, you can try meditating instead of sleeping. This can help reduce daytime sleepiness, improve productivity, and even benefit your health. A small study has found that mindfulness meditation, a practice that focuses on breathing and being aware of the present moment, can be beneficial.
Older meditators were found to spend more time in slow wave sleep (SWS) with higher theta-alpha power with background delta activity, along with a reduced electromyogram (EMG). During meditation, it is better to think of sleep and lack of brightness as the release of fatigue and stress. Vipassana meditation practices have been found to activate the anterior cingulate cortex and modulate parasympathetic activity during sleep. Sleep is meant to restore energy and help heal, while meditation is designed to reduce the stress that caused tiredness in the first place.
According to some Buddhist texts, a full night's sleep is about four hours for competent meditators. The evaluation of heart rate variability during REM sleep showed greater sympathetic activity in meditators than in controls. Although sleep and meditation share some common characteristics, they have slightly different effects on the body and mind. Falling asleep in meditation could also mean that your mind is releasing layers of emotional charge, a process necessary before a true meditative state (i).
This tendency has been demonstrated in many different studies, even for new meditators who begin with short periods of meditation. Bruce O'Hara from the University of Kentucky recommends replacing only half the amount of sleep with meditation. A study was conducted to assess whether meditation (or even simple rest with closed eyes) can be used to pay off some of the sleep debt, either through the neural synchronization observed by the EEG or through some other mechanism. Vipassana meditation appears to preserve SWS, suggesting that it could prevent age-related changes in slow-wave generating mechanisms. The second part of the study looked at the amount of sleep and mental acuity of experienced meditators compared to a group of non-meditators.
Sleep deprivation produced a slower initial reaction time (RT) in PVT that still improved significantly after a period of meditation.
