METHOD

Subjects

The subjects were 26 male volunteers who were attending a two day workshop on self-management for excessive tension through yoga. Their ages ranged from 34 - 54 yrs. (group average age = 43.0 ± 5.5 years), and none of them had previous experience of yoga or any relaxation procedures. All subjects were in the same occupation (middle managers from an electronic goods company) for at least two years prior to the test.

Design

Assessments ware made at the beginning and at the and of the two-day workshop. During the polygraph assessments the subjects were seated in a dimly lit, sound attenuated room.

Assessments

The Occupational Stress Index (OSI) (Srivastava & Singh, 1981) was administered before the program. The OSI has 46 statements to which the participant had to respond with Yes or No. For 29 statements 'Yes' was scored as '1' and 'No' as '0', whereas for 17 statements it was the reverse, i.e., 'No' was scored as '1', and 'Yes' as '0'.

The following data were recorded using a 4-channel polygraph (Medicaid Systems, Chandigarh, India): (i) EKG was recorded using standard limb lead 1 configuration. The EKG was digitized using a 12 bit analog-to-digital converter (ADC) at a sampling rate of 500 Hz. The data recorded were visually inspected off-line and only noise tree data were included for analysis (Raghuraj, Ramakrishnana, Nagendra, & Telles, 1998). The R waves were detected to obtain a point event series of successive R-R intervals, from which the beat to beat heart rate series was computed. Frequency domain analysis of heart rate variability (HRV) data was carried out for the 5-minute recordings. The mean heart rate was obtained from this record. The mean values were removed from the heart rate series to obtain the HRV values. The HRV power spectrum was obtained using Fast Fourier Transform (FFT). The power in HRV series in the following specific frequency bands was studied, viz., the very low frequency (VLF) band (0 - 0.05 Hz), low frequency (IF) band (0.05 - 0.15 Hz), and high frequency (HF) band (0.15 - 0.50 Hz). The low frequency and high frequency values were expressed as normalized units, which represent the relative value of each power component in proportion to the total power minus VLF component (IF norm = IF/ ((total power-VLF) × 100); H F norm = H F/ ((total power-VLF) × 100) (Task force of the European Society of Cardiology and the North American Society of Pacing and Electro-physiology, 1996). (ii) The breath rate (in cycles per minute) was calculated by counting the breath cycles in 60 second epochs, continuously. For each subject, the average of the values obtained during the 5-minute session was used for analysis..

Yoga practice

An idea from the traditional yoga texts that a combination of activating and pacifying practices may help reach mental equilibrium (Chinmayananda, 1984), was the basis for the main practice during the two-day program, called 'cyclic meditations'. It includes the practice of yoga postures interspersed with relaxation while supine, so as to have a combination of "activating" and "pacifying" practices (Nagendra & Nagarathna, 1997). Apart from the yoga practices the two-day stress management program also consists of a series of lectures (5 hours) on topics such as ancient Indian philosophical concepts about stress.

Data analysis

(i) Pro-post stress management program comparisons were based on a t- test for paired data.
(ii) The polygraph data of subjects with OSI greater than the median wore analyzed separately from data of subjects with OSI less than the median. These data were also compared (pre-post) with the paired t- test.