Over the past thirty years or more, yoga and associated meditation techniques have come to be accepted as important means of reducing effects of stress.[1
] A wide variety of studies in these fields have been done,[2
] and in one of them different techniques such as progressive muscular relaxation, biofeedback, relaxation, and mental imagery were compared by meta-analysis.[5
] One study concluded that different techniques produce different spectrum of effect sizes for different tasks.[6
] The early hypothesis by Benson[7
] that there is a universal ‘relaxation response’ that is same for any technique has been convincingly refuted.[8
] Rather it is recognized that each technique produces effects in specific brain regions, and that precise magnitude of benefits for a particular task depends on the extent to which that brain region is used in task performance.
Today, the most effective of these techniques are well accepted as being of substantial benefit for stress in the workplace and in other aspects of life, and are widely taught as specific coping skills, particularly for professionally incurred stress. These stress-reduction techniques have been found useful in reducing a variety of stress-related symptoms, such as anxiety, neuroticism, depression, and hypertension. For example, ‘Deep Breathing Meditation Exercises’ have been reported to decrease anxiety, nervousness, self-doubt, and concentration loss.[9
] They have also been found to improve measures of emotional intelligence.[10
] Such techniques are most effective when practiced daily for an extended period of time.[11
In addition to reduction in stress symptoms, beneficial effects of various relaxation techniques include: feeling of well-being, sense of calmness and relaxation in activity, improved sleep, less emotional reactivity, increased inner directedness (self-awareness), and improved self-care.[12
] Improved performance has also been found on a variety of psychological tests, such as IQ,[13
] Tower of London Test,[13
] Baddley Tests of Verbal and Spatial Memory,[15
] Six Letter Cancellation Test (SLCT),[17
] and so on.
In this study, the influence of yoga relaxation techniques on performance of the Digit–Letter Substitution Task (DLST) was investigated. The DLST depends on selective attention and memory. It is easily understood and performed and suitable for subjects of all ages, including school students. It was therefore given to participants in a 10-day personality development camp held for early teenage school students during their summer vacation. The two techniques chosen were the easily performed Cyclic Meditation (CM) developed at sVYASA,[18
] and the Supine Rest (SR) position known as ‘sleep posture’ (shavasana
), generally done at the end of yogasana practice. The reasons are as follows.
has been found to reduce physiological arousal,[19
] and to be effective in helping practitioners cope with stress manifestations, for example, Bera et al
. found recovery from induced physiological stress was significantly faster for supine posture with additional progressive relaxation, compared to resting, sitting in a chair, or plain shavasana
] In another study, a significant decrease in breath rate was noted after performance of the yoga-based Isometric Relaxation Technique (IRT), when compared to SR.[21
] IRT forms an integral part of the CM, which we now describe in detail.
CM combines ‘stimulating’ and ‘calming’ practices. Such yoga practice is described in the Mandukya Karika
, a text associated the Mandukya Upanishad
, which suggests that such a combination is helpful in attaining mental equilibrium. CM consists of the practice of yoga postures (asanas
) interspersed with periods of relaxation in shavasana. After the period of practice, significant reductions in oxygen consumption occur, compared to an equal period of shavasana
] CM has been found particularly effective in relieving stress, and is widely applied in professional stress management programs.
Recent studies on CM suggest that during the yoga posture phase, predominantly sympathetic activation occurs, whereas after CM, the parasympathetic nervous system becomes dominant.[24
] The overall result is a greater reduction in energy expenditure than in SR.[25
] CM has also been found to enhance the P300 wave in the evoked potential,[26
] a fundamental cognitive process involving attention and immediate memory.[27
Since the DLST involves memory and selective attention, it was hypothesized that CM would increase performance on the test. For convenience of subject availability, it was decided to study changes on DLST scores after performance of CM, compared to SR, in school students attending one of sVYASA’s smmer vacation 10-day personality development camps.