Immediate Effects of Suryanamaskar on Reaction Time and Heart Rate in Female Volunteers.

Suryanamaskar (SN), a yogic technique is composed of dynamic muscular movements synchronised with deep rhythmic breathing. As it may have influence on CNS, this study planned to investigate immediate effects of SN on reaction time (RT) and heart rate (HR). 21 female volunteers attending yoga classes were recruited for study group and 19 female volunteers not participating in yoga were recruited as external-controls. HR, auditory reaction time (ART) and visual reaction time (VRT) were recorded before and after three rounds of SN in study group as well as 5 minutes of quiet sitting in both groups. Performance of SN produced immediate decrease in both VRT and ART (P<0.001). This was significant when compared to self-control period (P<0.001) and compared to externalcontrol group, it decreased significantly in ART (p=0.02). This was pronounced when Δ% was compared between groups (P<0.001). HR increased significantly following SN compared with both self-control (p=0.025) and external-control group (p=0.032). Faster reactivity may be due to intermediate level of arousal by conscious synchronisation of dynamic movements with breathing. Rise in HR is attributed to sympathetic arousal and muscular exertion. We suggest that SN may be used as an effective training means to improve neuro-muscular abilities.

Immediate cardiovascular effects of pranava pranayama in hypertensive patients.

Slow, deep, pranayama - based breathing training has been shown to be effective in reducing blood pressure (BP). The present study was undertaken to determine immediate effects of performing pranava pranayama on cardiovascular parameters in hypertensive patients. 29 hypertensive patients who were on medical treatment and also attending yoga sessions were recruited for the present study. Supine heart rate (HR) and BP were recorded before and after performance of pranava pranayama for five minutes. Post intervention statistical analysis revealed a significant (P<0.05) reduction in systolic pressure (SP) and a more significant (P<0.01) reduction in HR, pulse pressure and double product (Do P). The reduction in rate-pressure product (RPP) was highly significant (P<0.001). Pranava pranayama is effective in reducing HR and SP in hypertensive patients within five minutes of the practice. This may be due to a normalization of autonomic cardiovascular rhythms as a result of increased vagal modulation and/or decreased sympathetic activity and improved baroreflex sensitivity along with an augmentation of endogenous nitric oxide production. Our findings have potential therapeutic applications in day-to-day as well as clinical situations where blood pressure needs to be brought down at the earliest. The significant fall in RPP and Do P signifies a reduction in oxygen consumption and work done by the heart. It is concluded that pranava pranayama, a simple and cost effective technique can be used in the management of hypertensive patients in addition to the regular medical management. Further studies are required to enable a deeper understanding of the mechanisms involved and its usefulness in the long- term management of hypertension.

Immediate effect of mukha bhastrika (a bellows type pranayama) on reaction time in mentally challenged adolescents.

Mentally challenged individuals are known to have slower speed of reaction. As a previous study has shown immediate improvement in reaction time (RT) following mukha bhastrika, a bellows type of pranayama, we planned to study the effect of this pranayama in mentally challenged adolescents. 34 mentally challenged adolescents (15.1±0.806 y) studying in a school for Special Needs were recruited as they have been receiving yoga training once a week for more than 3 years. Exclusion criteria were inability to either perform mukha bhastrika or to understand procedure for testing RT. Visual (VRT) and auditory reaction time (ART) was measured using RT apparatus before and after nine rounds of mukha bhastrika and a control period of ten minutes of normal activities to rule out any test-retest practice effect. Analysis of non-intervention period values showed that the reliability in terms of reproducibility of the observation for both VRT (r=0.87) and ART (r=0.95) was excellent. Mukha bhastrika produced an immediate and significant decrease in both VRT and ART. There was a statistically significant decrease in VRT (P<0.0001) from 296.15 ms±13.49 to 263.59 ms±12.53 and ART (P<0.0001) from 247.88 ms±14.33 to 217.35 ms±11.36 following mukha bhastrika. Decrease in RT signifies improved central neuronal processing ability. This may be due to greater arousal and faster rate of information processing, improved concentration and/or ability to ignore or inhibit extraneous stimuli. Mukha bhastrika may be altering afferent inputs from abdominal and thoracic regions, in turn modulating activity at ascending reticular activating system and thalamo-cortical levels. It is suggested that yogic breathing techniques like mukha bhastrika be used as an effective means of improving neuromuscular abilities in special children.

Modulation of cardiovascular response to exercise by yoga training.

This study reports the effects of yoga training on cardiovascular response to exercise and the time course of recovery after the exercise. Cardiovascular response to exercise was determined by Harvard step test using a platform of 45 cm height. The subjects were asked to step up and down the platform at a rate of 30/min for a total duration of 5 min or until fatigue, whichever was earlier. Heart rate (HR) and blood pressure response to exercise were measured in supine position before exercise and at 1, 2, 3, 4, 5, 7 and 10 minutes after the exercise. Rate-pressure product [RPP = (HR x SP)/100] and double product (Do P = HR x MP), which are indices of work done by the heart were also calculated. Exercise produced a significant increase in HR, systolic pressure, RPP & DoP and a significant decrease in diastolic pressure. After two months of yoga training, exercise-induced changes in these parameters were significantly reduced. It is concluded that after yoga training a given level of exercise leads to a milder cardiovascular response, suggesting better exercise tolerance.

Effect of yoga training on handgrip, respiratory pressures and pulmonary function.

Although there are a number of reports on the effect of yoga training on pulmonary functions, very few studies have been undertaken on the effect of yoga training on respiratory pressures and handgrip endurance. Hence the present work was planned to study the effect of yoga training on hand grip strength (HGS), hand grip endurance (HGE), maximum expiratory pressure (MEP), maximum inspiratory pressure (MIP), forced expiratory volume (FEV), forced expiratory volume in first second (FEV1) and peak expiratory flow rate (PEFR). 20 school children in the age group of 12 to 15 years were given yoga training (asans and pranayams) for 6 months. 20 age and gender-matched students formed the control group. Yoga training produced statistically significant (P < 0.05) increase in HGS and HGE. MEP, MIP, FEV, FEV1 and PEFR also increased significantly (P < 0.001) after the yoga training. In contrast, the increase in these parameters in the control group was statistically insignificant. Our study shows that yoga training for 6 months improves lung function, strength of inspiratory and expiratory muscles as well as skeletal muscle strength and endurance. It is suggested that yoga be introduced at school level in order to improve physiological functions, overall health and performance of students.

Acute effect of Mukh bhastrika (a yogic bellows type breathing) on reaction time.

Reaction time (RT) is an index of the processing ability of central nervous system and a simple means of determining sensory-motor performance. It has been reported that yoga training improves human performance including central neural processing. Earlier studies from our laboratories have shown that yoga training produces a significant decrease in visual reaction time (VRT) and auditory reaction time (ART). The present work was planned to determine if mukh bhastrika (a yogic technique in which breath is actively blasted out in 'whooshes' following a deep inspiration) has any effect on central neural processing by studying its effect on RT. 22 healthy schoolboys who were practising yoga for the past three months were recruited for the present study. VRT and ART were recorded before and after nine rounds of mukh bhastrika. Mukh bhastrika produced a significant (P < 0.01) decrease in VRT as well as ART. A decrease in RT indicates an improved sensory-motor performance and enhanced processing ability of central nervous system. This may be due to greater arousal, faster rate of information processing, improved concentration and/ or an ability to ignore extraneous stimuli. This is of applied value in situations requiring faster reactivity such as sports, machine operation, race driving and specialised surgery. It may also be of value to train mentally retarded children and older sports persons who have prolonged RT.

Effect of pranayam training on cardiac function in normal young volunteers.

Systolic time intervals (STI) are non-invasive and sensitive tests for measuring the ventricular performance. It has been reported that practice of pranayam modulates cardiac autonomic status and improves cardio-respiratory functions. Keeping this in view, the present study was designed to determine whether pranayam training has any effect on ventricular performance as measured by STI and cardiac autonomic function tests (AFT). Twenty four school children were randomly divided into two groups of twelve each. Group I (pranayam group) subjects were given training in nadishuddhi, mukh-bhastrika, pranav and savitri pranayams and practiced the same for 20 minutes daily for a duration of 3 months. Group II (control group) subjects were not given any pranayam training. STI (QS2, LVET and PEP) and AFT (RRIV and QT/QS2) were measured in both the groups at the beginning and again at the end of three months study period. Pranayam training produced an increase in RRIV and a decrease in QT/QS2, suggesting an enhanced parasympathetic and blunted sympathetic activity respectively. QS2, PEP and PEP/LVET increased significantly, whereas LVET was reduced significantly in pranayam group. In contrast, the changes in STI and AFT were much less marked in the control group. Our study shows that three months of pranayam training modulates ventricular performance by increasing parasympathetic activity and decreasing sympathetic activity. Further studies on a larger sample size may illustrate the underlying mechanism(s) involved in this alteration.

Modulation of cold pressor-induced stress by shavasan in normal adult volunteers.

Shavasan is known to enhance one's ability to combat stressful situations. The present study was planned to determine if shavasan could modulate the physiological response to stress induced by cold pressor test (CPT) and the possible mechanisms involved. Ten normal adults were taught shavasan and practiced the same for a total duration of seven days. RR interval variation (RRIV), deep breathing difference (DBD), and heart rate, blood pressure & rate-pressure-product (RPP) response to CPT were measured before and immediately after shavasan. Shavasan produced a significant increase in DBD and an appreciable but statistically insignificant increase in RRIV suggesting an enhanced parasympathetic activity. Significant blunting of cold pressor-induced increase in heart rate, blood pressure and RPP by shavasan was seen during and even five minutes after CPT suggesting that shavasan reduces the load on the heart by blunting the sympathetic response. It is concluded that shavasan can enhance one's ability to withstand stress induced by CPT and this ability can be achieved even with seven days of shavasan training.