Abstract
Background: Yogic relaxation practices produce consistent physiological changes. Various studies are on before and after effects of yoga. There is limited study on physiological changes during yoga.

Aim and Objectives: In this study, we explored physiological changes during two yogic relaxation practices using polysomnography instrument.

Materials and Methods: Ethical approval for the study was obtained from the Institute Ethics Committee, All India Institute of Medical Sciences, New Delhi. Data were collected in a still, (supine position lying face upwards in Shavasan, before and after performing asanas) for 5 min, 10 min during, 5 min after the yogic relaxation practices (Shavasan and Makrasan). Recording were taken continuously after bio calibration as baseline1, shavasan, baseline2, makrasan, post makrasan. The data of pulse rate, respiratory rate and SPO2 were analyzed using Statistical Package for the Social Sciences version 20.

Result: Among 18 participants of age 18–45 years, 11 male and 7 female were participated. Comparison of selected parameters (respiration rate, SPO2, heart rate [HR]) in different condition (baseline1, shavasan, baseline2, makarasan, post makarasan) was analyzed. Comparison of HR in different condition is highly significant; HR varies in makarasan significantly from baseline1, shavasan and baseline2. SPO2 changes significantly vay among different conditions. Changes in respiratory rate are not significant in different conditions. Correlation of age with body mass index is significant in post makarasan variable.

Conclusion: Physiological changes occur differently in two different yogic relaxation practices. Further detailed study with large sample size, blood pressure monitoring and in well-trained individuals will provide more information.

Key words: Physiological Changes; Shavasan; Makrasan; Heart Rate; Abdominal Breathing