The brain in deep sleep and samadhi Therefore, our brain behaves similarly in deep sleep and deep meditation. Another physiological similarity between sleep and meditation has to do with its effect on heart rate and breathing patterns. In both deep sleep and meditation, both heart rate and breathing rate tend to decrease. Meditation and sleep are hypometabolic states, in which breathing and other bodily activities decrease.
Both release tensions, but the rest that meditation provides is much deeper than the rest that comes from sleep. Therefore, the deepest ingrained impressions, or samskaras, leave the system. But why? We know that a regular practice of meditation can cause changes in the body that are similar to the changes that occur during sleep. The restorative alertness that you may experience with meditation is associated with slowing heart rate, reduced metabolism, and changes in the nervous system that reduce arousal that occurs during sleep.
Compared to the state of wakefulness, during sleep, our breathing is slower and deeper, but not much less, in terms of oxygen intake. Whereas in meditation, as the mind calms down and our body (therefore) needs less oxygen to function, the respiratory rate will often drop dramatically. The health benefits of meditating regularly are well documented, but the effects of not meditating are definitely not as disastrous as sleep deprivation. These results suggest that meditation provides at least short-term performance improvement, even in novice meditators.
Twenty-three control subjects were also selected in India for comparisons of total sleep time relative to the seven meditators. Perhaps the main thing to keep in mind is that, as far as the body is concerned, meditation and sleep are two different things. This experiment suggests that meditation plays a performance-enhancing and perhaps restorative role even in novice meditators. Meditators had significantly shorter sleep durations than non-meditators (5.2 vs 7.8 hours per day; F 1.28% 3D 54.183, p.
Neuroimaging studies are beginning to support the idea that a meditation practice promotes greater wakefulness and less propensity for sleep as it progresses in intensity. During your meditations, please don't try to find out if you were sleeping or meditating deeply at certain times. A major difficulty in assessing whether meditation can replace part of sleep is that sleep functions are not well understood and there is no direct measurement of the need for sleep. For some of us, it will be necessary to sleep a lot and get tired during meditation and sometimes even after meditation.
In experiments with experienced long-term meditators, sleep duration was measured using sleep diaries and actigraphy. You can already notice a big difference between sleep and meditation: in one, consciousness is suspended and in the other, the mind is focused on purpose. Sleep deprivation produced a slower initial reaction time (RT) in PVT that still improved significantly after a period of meditation.