Some research indicates that the practice of yoga and yoga meditation may improve sleep quality and reduce sleep disturbance (Bower et al., 2005; Harrison et al., 2004; Kaye, 1985; Sahajpal & Ralte, 2000). Yoga has also been identified as a potential treatment protocol for chronic insomnia (Khalsa, 2004). When older adults were trained in yoga for six months, they showed a significant decrease in the time taken to fall asleep and a significant increase in the total number of hours of sleep, as compared to control groups (Manjunath & Telles, 2005). In fact, Brown and Gerbarg (2005b) report that insomnia may be one of the first symptoms to respond to daily yoga practice, through the ability of breath techniques to “quiet the mind, reduce obsessive worry, and induce a state of physical and mental calmness conducive to sleep” (p. 712).
One potential explanation for the impact of yoga and meditation practices on sleep quality relates to yoga’s impact on melatonin levels. Tooley, Armstrong, Norman, and Sali (2000) measured melatonin levels in experienced meditators on two different occasions: on a night when they meditated under specific laboratory conditions, and on a night when they sat quietly with eyes open (control condition) under the same laboratory conditions. On the meditation nights, they had significantly higher plasma melatonin levels than on the control nights. It was proposed that “facilitation of higher physiological melatonin levels at appropriate times of day might be one avenue through which the claimed health promoting effects of meditation occur” (p. 69).