An open-trial single arm pre-post study design was adopted for this study. The data were collected using a self-report questionnaire from the participants enrolled for the Happiness Program (SKY workshop) at The Art of Living International Center, Bangalore. A standardized questionnaire that measured the quality of sleep for an individual was used for assessment. The assessment was conducted at three different time points: before the intervention, i.e., at the beginning of the first day of the workshop (Pre), immediately after the workshop (Post), and lastly after the recommended 40-day daily practice of the Sudarshan Kriya Yoga (Day 40).
The study was conducted at The Art of Living International Center Bangalore, India, between August 2018 and August 2019. The Happiness Program (SKY workshop) was conducted at the center each weekend from Friday to Sunday. Participants included adults above 18 years of age. Both genders were included in this study. The educational and economic backgrounds varied among the study population, as did dietary habits. All those who had registered for the Happiness Program, were notified about the study in detail on the very first day, before the first session of the program. Participation was sought only from those who had no previous experience of SKY. Those who agreed to participate in this study were recruited with their informed consent. The Institutional Review Board of the Sri Sri Institute for Advanced Research in India approved this study.
Participants were trained in SKY over 3-days. During the program, all the participants were provided “Home Going instructions” which enabled them to practice SKY independently at home. On the last day of the program, they practiced SKY on their own with the instructor on site, to ensure that they were practicing the technique correctly. In addition, daily follow-up sessions were conducted and weekly follow-up sessions were provided, where participants practiced along with the teacher and could clarify any questions or doubts. During these sessions, instructors were also able to guide them and ensure they were practicing correctly. Participants were encouraged to attend the daily and weekly sessions. Attendance logs were maintained. Online support tools and an app was also provided to the participants with instructions for the pranayamas and SKY to facilitate their practice. Weekly phone calls were made to enhance retention.
The study questionnaire was filled by the participants before the commencement of the program. Their personal details were kept confidential. On the last day of the program, the same set of questionnaires were once again completed by them. After 40 days of the completion of the program, subjects were requested through email and phone to complete the last stage of the study assessment. During the 40 day assessment, subjects were asked the following question “How frequently have you been practicing Sudarshan Kriya? They could respond as: Daily; 2–3 times a week or Once a week. Based on their response and maintained attendance logs, the long term effect of SKY practice on sleep was calculated.
A total of 473 people participated in the Pre and Post evaluation, while 112 subjects participated in Day 40 assessment.
The Happiness Program is a 3-day life-skills workshop focusing on body, breath, and mental wellness. The core of the program includes a yogic breathing technique called the Sudarshan Kriya Yoga (SKY), along with interpersonal processes and activities. Trained teachers of The Art of Living facilitate the workshop, guiding participants through the SKY process, which takes an hour and 15 min. A shorter form of SKY, 35 min, is also taught to the participants for daily home practice. For the study, participants were encouraged to practice the shorter version individually for 40 days after the commencement of the workshop.
A typical SKY session consists of four stages, each with its own distinct yogic breathing pattern, done while sitting in various postures (Ujjayi, Bhastrika, Om, and Sudarshan Kriya), interspersed with normal breathing. The first type, Ujjayi, involves deep, long breaths with attention to the sensation of the breath touching the throat. The pace is slow, at the rate of 2–4 breaths per minute (bpm). The second, Bhastrika, involves rapid and forceful exhalation at the rate of 25–30 bpm. This is followed by saying Om thrice, with prolonged expiration. The last stage, Sudarshan Kriya, involves rhythmic breathing at three different paces—slow breaths (15–20 bpm), medium (40–50 bpm), and fast (60–80 bpm). The entire sequence is done in a seated posture, with eyes closed. The aim is to elicit a mind–body response of quiet, calm alertness, experienced as a tranquil state in the rest period immediately following the practice.
The Pittsburgh Sleep Quality Index (PSQI) was used to collect data for the study. It is a standardized self-report sleep questionnaire that has been used across multiple populations in many languages. Consisting of 19 individual questions, it is a broad subjective measure that attempts to assess and measure seven components of sleep, including sleep quality, sleep latency (the time taken to fall asleep), duration of sleep, habitual sleep efficiency, sleep disturbances, use of sleep medication, and daytime dysfunction. Each component is based on a 0–3 Likert scale, and the component scores are aggregated to get a global PSQI score. A global PSQI score of 5 or more indicates poor sleep quality.
PSQI is one of the oldest scales, widely used in studies on yoga in India, with good reliability and sensitivity. Most of the items of PSQI are organized as multiple choice questions and are brief and easy to understand and answer. PSQI scale takes only 5–10 min to complete, and hence, was found appropriate for this study (Fig. 1).
Participants were assessed at three-time points Pre, Post, and Day 40. The data were matched using their email addresses and phone number. The responses were then grouped by age, gender, and frequency of SKY practice. The mean score and Standard Deviation (SD) were calculated for each combination. The paired-sample t-test was used to compare differences between Pre and Post assessments, and Pre and Day 40 assessment. Validated software MS Excel 2007 (which has required statistical tests/functions) and IBM SPSS V25 were used for statistical analysis. In addition, Cronbach’s alpha was calculated to measure the internal consistency and reliability of the data. Cohen’s d value was calculated to determine the effect size. Difference in mean value and pair-wise comparison was calculated using one-way ANOVA test, at 0.05 significance level. Since the data collected were on an ordinal scale, the following formula was used to calculate maximum sample size for a given % of error of estimate.
n = 0.25 × Z2/E2 where Z = 1.96 for confidence level of 95% and E is error of estimate.
To reduce the effect of Type 1 error due to multiple comparisons, Bonferroni correction was applied wherever possible.