(7) Sleep Drives Metabolite Clearance from the Adult Brain
Lulu Xie,* , Hongyi Kang , Qiwu Xu, Michael J. Chen, Yonghong Liao, Meenakshisundaram Thiyagarajan, John OíDonnell, Daniel J. Christensen, Charles Nicholson, Jeffrey J. Iliff, Takahiro Takano1, Rashid Deane, and Maiken Nedergaard,Ü http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3880190/pdf/nihms540586.pdf
(9) Regulation of Sleep and Growth Hormone in Adolescent Depression http://www.sciencedirect.com/science/article/pii/S0890856709640764
Deep sleep and VLF/HF ratio
There is a good relationship between VLF/HF ratio and the deep sleep phase:
During deep sleep phase, VLF is significantly lower than in the other sleep stages; and HF is significantly higher (1).
(1) Spectral Analysis of Heart Rate Variability in Sleep P. BUŠEK, J. VAŇKOVÁ, J. OPAVSKÝ , J. SALINGER, S. NEVŠÍMALOVÁ
Physiol. Res. 54: 369-376, 2005
Deep Sleep & Movements
The gyroscope of the iPhone allows the recording of your night movements. This movement analysis can be compared and related to the depp sleep stages extracted from the heart data analysis.
The pink curve displays the movement analysis
Deep Sleep & musical signature
Different parts of the night can easily be visualized through the color display of the musical frequencies (music notes) extracted from the heart data analysis.
Deep Sleep & Lucid Dreams - Deep Meditation State
Slow-Wave Sleep can also be achieved through deep meditation state
« Subjectively deep sleep is a time of nearly complete disengagement from the environment… There is a more subtle state of awareness that may be developed through meditation and can be thought of as being more subtle and like that of the dreaming state of consciousness. The deepest level of consciousness, in this scheme, is the one in which it is possible to become aware of the emptiness in which all phenomenon are thought to occur. According to the integral philosopher Ken Wilber, it is possible, with training in advanced meditation, for people to be aware of the subtler states of consciousness, including the states of dreaming and even deep sleep. »*