The word yoga means universal communionIYENGAR, 2007which demonstrates that the purpose of yoga is also to find inner peace, not just physical health. Yoga sessions are composed of slow movements and cadenced breathing, body postures (asanas), controlled breathing (pranayama), contemplative meditations, relaxation and prayersGOVINDARAJ; KARMANI; VARAMBALLY; GANGADHAR, 2016).
The observed effects of the regular practice of yoga are diverse, and include reduced cortisol concentrationsBRAINARD; PRATAP; REED; LEVITT et al., 1997increased concentration of brain-derived neurotrophic factor (BNDF), oxytocinJAYARAM; VARAMBALLY; BEHERE; VENKATASUBRAMANIAN et al., 2013; NAVEEN; THIRTHALLI; RAO; VARAMBALLY et al., 2013and serotoninWALTON; PUGH; GELDERLOOS; MACRAE, 1995reduced pain perceptionLEE; MOON; KIM, 2014greater activation of the parasympathetic systemGOPAL; LAKSHMANAN, 1972reduced stress levelsPANJWANI; GUPTA; SINGH; SELVAMURTHY et al., 1995improved selective attentionVELIKONJA; ČURIĆ; OŽURA; JAZBEC, 2010as well as improved mood and quality of lifeOKEN; ZAJDEL; KISHIYAMA; FLEGAL et al., 2006Considering all these factors, the objective of this text is to elucidate the effects that the practice of yoga and meditation have on the quality of sleep.
Effects of yoga practice on sleep
Observed changes in sleep architecture after yoga and meditation practice
The effects of meditation on sleep were first reported by Mason and colleagues in 1997MASON; ALEXANDER; TRAVIS; MARSH et al., 1997The researchers observed that experienced practitioners spent more time in slow-wave and REM sleep, and had reduced electromyographic activity. With this work, they built new avenues to discover the relationship between meditation and sleep, and most of the studies that followed corroborated their results.
Sulehka and Ravindra compared the sleep of experienced practitioners and non-practitioners of Vipassana meditation, and found a greater proportion of slow-wave sleep and REM sleep in experienced practitioners and, in addition, they also had a greater number of sleep cyclesPATTANASHETTY; SATHIAMMA; TALAKKAD; NITYANANDA et al., 2010; SULEKHA; THENNARASU; VEDAMURTHACHAR; RAJU et al., 2006).
Evidence on the effectiveness of yoga and meditation in insomnia
A systematic review with meta-analysis investigated the effect of mindfulness practice on the sleep quality of patients with insomniaGONG; NI; LIU; ZHANG et al., 2016The authors evaluated 6 randomized clinical trials (which included 330 participants) and concluded that mindfulness practice had positive effects to improve sleep quality in patients with insomnia, being an auxiliary therapy option in the treatment of this disorder
Seven weeks in a mindfulness program resulted in positive effects improving subjective insomnia, sleep quality, daytime sleepiness, and sleep impairment in patients with fibromyalgiaAMUTIO; FRANCO; SÁNCHEZ-SÁNCHEZ; PÉREZ-FUENTES et al., 2018There is also evidence demonstrating improvements in insomnia in cancer patientsMUSTIAN, 2013; RAO; VADIRAJA; NAGARATNA; GOPINATH et al., 2017; ZEICHNER; ZEICHNER; GOGINENI; SHATIL et al., 2017).
In another protocol, the practice of yoga was offered to elderly people with insomnia complaints and, after the intervention, the subjective sleep quality improved significantlyHALPERN; COHEN; KENNEDY; REECE et al., 2014).
Evidence demonstrating beneficial effects of yoga and meditation practice in the short, medium and long term
A study aimed to compare the quality of sleep after a day with yoga practice and without yoga practice in experienced individuals. Participants' sleep was assessed using polysomnography and the yoga session lasted 22 minutes and 30 seconds. The control situation was performed in shavasana or corpse pose for the same 22 minutes and 30 seconds. During the night of sleep, a higher proportion of slow-wave sleep was observed, as well as a greater perception of recovery upon awakening compared to when there was no practicePATRA; TELLES, 2009In addition, the number of awakenings each hour during sleep was lower after yoga practice.
A study carried out by Guerra et al. showed that the practice of 8 weeks of meditation (30 minutes per week) was effective in reducing the time awake after sleep onset, sleep onset latency and subjective sleep perception obtained through thePittsburgh Sleep Quality Index – PSQI) in healthcare professionals. In addition, heart rate during sleep was 3% lower in the post-intervention assessment. Sleep assessment was performed using polysomnography and the results demonstrate that positive effects from meditation practice can be observed even in small “dosesGUERRA; SANTAELLA; D’ALMEIDA; SANTOS-SILVA et al., 2020).
Finally, in a protocol that offered daily yoga practice to volunteers with at least 2 years of experience, PSQI scores and sleep onset latency were lower in the yoga-practicing group (compared to the control group)BANKAR; CHAUDHARI; CHAUDHARI, 2013).
The practice of yoga and meditation promotes benefits throughout the body, improving the general health and well-being of practitioners. Regarding sleep quality, evidence shows that the practice promotes a reduction in sleep onset latency, as well as in the time awake after sleep onset, in addition to causing positive changes in sleep architecture, resulting in a higher proportion of wave sleep and REM sleep.
Thus, as it is a cost-free practice with no side effects, and considering that its beneficial effects are observed in all age groups, it can be a great strategy to improve the sleep quality of the entire populatio
Sleep pattern assessment
Actigraphy is a non-invasive technique that can be used to assess sleep pattern and sleep-wake rhythm. The actigraph is a wristwatch-like device that contains light, motion, and temperature sensors. Through this information, it is possible to extract data regarding variables such as total sleep time, latency to sleep onset, time awake after sleep onset, sleep efficiency, time awake and variables related to rhythm, such as cosinor, spectrogram, periodogram, and non-parametric variables such as L5, M10, IS and IV.