Practicing yoga has been shown to improve motor functions and attention. Though attention is required for fine motor and discrimination tasks, the effect of yoga breathing techniques on fine motor skills and visual discrimination has not been assessed.
To study the effect of yoga breathing techniques on finger dexterity and visual discrimination.
Materials and Methods:
The present study consisted of one hundred and forty subjects who had enrolled for stress management. They were randomly divided into two groups, one group practiced high frequency yoga breathing while the other group practiced breath awareness. High frequency yoga breathing (kapalabhati, breath rate 1.0 Hz) and breath awareness are two yoga practices which improve attention. The immediate effect of high frequency yoga breathing and breath awareness (i) were assessed on the performance on the O′Connor finger dexterity task and (ii) (in) a shape and size discrimination task.
There was a significant improvement in the finger dexterity task by 19% after kapalabhati and 9% after breath awareness (P<0.001 in both cases, repeated measures ANOVA and post-hoc analyses). There was a significant reduction (P<0.001) in error (41% after kapalabhati and 21% after breath awareness) as well as time taken to complete the shape and size discrimination test (15% after kapalabhati and 15% after breath awareness; P<0.001) was also observed.
Both kapalabahati and breath awareness can improve fine motor skills and visual discrimination, with a greater magnitude of change after kapalabhati.
Finger dexterity; shape and size discrimination; yoga breathing
This study assessed the effect of alternate nostril yoga breathing (nadisuddhi pranayama) on P300 auditory evoked potentials compared to a session of breath awareness of equal duration, in 20 male adult volunteers who had an experience of yoga breathing practices for more than three months. Peak amplitudes and peak latencies of the P300 were assessed before and after the respective sessions. There was a significant increase in the P300 peak amplitudes at Fz, Cz, and Pz and a significant decrease in the peak latency at Fz alone following alternate nostril yoga breathing. Following breath awareness there was a significant increase in the peak amplitude of P300 at Cz. This suggests that alternate nostril yoga breathing positively influences cognitive processes which are required for sustained attention at different scalp sites (frontal, vertex and parietal), whereas breath awareness brings about changes at the vertex alone.
Alternate nostril yoga breathing; P300; Breath awareness; Cognitive processes
Beneficial effects of Yoga have been postulated to be due to modulation of the autonomic nervous system.
To assess the effect of Isha Yoga practices on cardiovascular autonomic nervous system through short-term heart rate variability (HRV).
Design of the Study:
Short-term HRV of long-term regular healthy 14 (12 males and 2 females) Isha Yoga practitioners was compared with that of age- and gender-matched 14 (12 males and 2 females) non-Yoga practitioners.
Methods and Materials:
ECG Lead II and respiratory movements were recorded in both groups using Polyrite during supine rest for 5 min and controlled deep breathing for 1 minute. Frequency domain analysis [RR interval is the mean of distance between subsequent R wave peaks in ECG], low frequency (LF) power, high frequency (HF) power, LF normalized units (nu), HF nu, LF/HF ratio] and time domain analysis [Standard Deviation of normal to normal interval (SDNN), square of mean squared difference of successive normal to normal intervals (RMSSD), normal to normal intervals which are differing by 50 ms (NN50), and percentage of NN50 (pNN50)] of HRV variables were analyzed for supine rest. Time domain analysis was recorded for deep breathing.
Results showed statistically significant differences between Isha Yoga practitioners and controls in both frequency and time domain analyses of HRV indices, with no difference in resting heart rate between the groups.
Practitioners of Isha Yoga showed well-balanced beneficial activity of vagal efferents, an overall increased HRV, and sympathovagal balance, compared to non-Yoga practitioners during supine rest and deep breathing.
Cardiovascular ANS; heart rate variability; Isha Yoga
Previously alternate nostril yoga breathing (anuloma-viloma pranayama) was shown to reduce the blood pressure (BP) in people with hypertension. An elevated BP has been associated with poor performance in certain tasks requiring attention and co-ordination. The Purdue pegboard task assesses manual dexterity and eye-hand co-ordination.
In the present study there were ninety participants with essential hypertension. Their ages ranged from 20 to 59 years (group average age ±S.D., 49.7±9.5 years; sixty males). Participants were randomized as three groups, with thirty participants in each group. One group practiced alternate nostril yoga breathing for 10 minutes, the second group practiced breath awareness for the same duration and the third group was given a control intervention (i.e., reading a magazine with neutral content). Assessments were taken before and after the interventions for participants of the three groups. Assessments included the blood pressure and performance in the Purdue pegboard task. Data were analyzed with a repeated measures ANOVA and post-hoc analyses were Bonferroni adjusted.
Following alternate nostril breathing (ANYB) there was a significant decrease in systolic and diastolic blood pressure (p<0.001 and p<0.05), and an improvement in Purdue pegboard task scores for both hands (p<0.05), and for the right hand (p<.001). Breath awareness (the control session) also showed a significant decrease in systolic blood pressure (p<0.05). The right hand scores improved in the group reading a magazine (p<0.05).
The results suggest that the immediate effect of ANYB is to reduce the BP while improving the performing in a task requiring attention, bimanual dexterity and visuo-motor co-ordination.
hypertension; alternate nostril yoga breathing; blood pressure; Purdue pegboard task; attention; visuo-motor co-ordination; bi-manual dexterity
The effect of positive expiratory pressure breathing, alone and in combination with coughing, was investigated in eight patients with cystic fibrosis. Functional residual capacity and total lung capacity was measured with a body plethysmograph before, during, and immediately after breathing with expiratory pressure of 5 and 15 cm H2O, and after a coughing period. The positive expiratory pressure breathing was carried out five times for two minutes with a two minute interval between each period. Mucus transport was measured in a peripheral lung region and over the whole lung by a radioactive aerosol tracer technique. Clearance measurements were carried out continuously during positive expiratory pressure breathing and during a control period. Two minutes' breathing with an expiratory pressure of 5 and 15 cm H2O caused an increase in mean (SEM) functional residual capacity from 2.6 (0.1) to 3.6 (0.3) and 4.4 (0.5) 1 and an increase in total lung capacity from 5.1 (0.2) to 5.9 (0.3) and 6.9 (0.4) 1. Lung volumes were higher during breathing with an expiratory pressure of 15 cm H2O than with 5 cm H2O; both returned to baseline values immediately after positive expiratory pressure breathing. Spontaneous mucus clearance and mucus clearance by coughing were not influenced by positive expiratory pressure breathing at either expiratory pressure. Thus in patients with cystic fibrosis positive expiratory pressure breathing increases lung volumes in relation to the expiratory pressure imposed; these changes in lung volume did not, however, lead to an improvement of mucus transport.
One month of yoga training has been shown to reduce the pulse rate voluntarily without using external cues. Hence, the present study was designed to understand the strategies used by yoga practitioners and autonomic changes associated with voluntary heart rate reduction.
Materials and Methods:
Fifty volunteers (group mean age ± S.D., 25.4 ± 4.8 years; 25 males) were assessed in two trials on separate days. Each trial was for 12 minutes, with a ‘pre’ state and ‘during’ state of 6 minutes each. For both trials the ‘pre’ state was relaxation with eyes closed. In the ‘during’ state of Trial I, subjects were asked to voluntarily reduce their heart rate using a strategy of their choice. From their responses to specific questions it was determined that 22 out of 50 persons used breath regulation as a strategy. Hence, in the ‘during’ state of Trial II, subjects were asked to voluntarily reduce their heart rate by breath regulation.
In the first trial, the heart rate was reduced by an average of 19.6 beats per minute and in the second trial (with breath regulation exclusively) an average decrease of 22.2 beats per minute was achieved.
Hence, the strategy used did not markedly alter the outcome.
Breath regulation; voluntary heart rate reduction; yoga
An earlier study showed that a week of yoga practice was useful in stress management after a natural calamity. Due to heavy rain and a rift on the banks of the Kosi river, in the state of Bihar in north India, there were floods with loss of life and property. A week of yoga practice was given to the survivors a month after the event and the effect was assessed.
Twenty-two volunteers (group average age ± S.D, 31.5 ± 7.5 years; all of them were males) were randomly assigned to two groups, yoga and a non-yoga wait-list control group. The yoga group practiced yoga for an hour daily while the control group continued with their routine activities. Both groups' heart rate variability, breath rate, and four symptoms of emotional distress using visual analog scales, were assessed on the first and eighth day of the program.
There was a significant decrease in sadness in the yoga group (p < 0.05, paired t-test, post data compared to pre) and an increase in anxiety in the control group (p < 0.05, paired t-test, post data compared to pre).
A week of yoga can reduce feelings of sadness and possibly prevent an increase in anxiety in flood survivors a month after the calamity.
Clinical Trials Registry of India: CTRI/2009/091/000285
The influence of breathing pattern on lung deposition and bronchodilator response to nebulised salbutamol is uncertain. Three different breathing patterns were assessed in eight patients with chronic stable asthma. Salbutamol solution (2.5 mg in 4 ml) mixed with technetium-99m labelled human serum albumin was nebulised by an Acorn nebuliser at a flow rate of 6 litres a minute. Particles with a mass median aerodynamic diameter of 4.8 microns were produced for inhalation by (a) tidal breathing, (b) six tidal breaths followed by three deep breaths, and (c) six tidal breaths followed by three deep breaths with a five second breath hold after each breath. Each breathing pattern was continued for four minutes. There was no significant difference in the percentage of radioaerosol deposited in the lung or in the distribution of radioaerosol within the lung as assessed by gamma camera imaging. Changes in bronchodilator responses as measured by peak expiratory flow rate (PEF), forced expiratory volume in one second (FEV1), and forced vital capacity (FVC) 30, 45, and 60 minutes after inhalation were similar for the three studies. The mean (SEM) maximum percentage change in FEV1 was 44 (7.1), 47 (9.2), and 51 (8.4) for studies 1, 2, and 3 respectively. The percentage of nebulised solution deposited in the body was also similar for the three breathing patterns--that is, 11-13%, of which 98% entered the lung. This study shows that inhaling a nebulised aerosol by tidal breathing, the simplest method, is as effective as tidal breathing with deep breaths with or without a breath hold.
The incidence of bronchial asthma is on increase. Chemotherapy is helpful during early course of the disease, but later on morbidity and mortality increases. The efficacy of yoga therapy though appreciated is yet to be defined and modified. Aim: To study the effect of breathing exercises (pranayama) in patients with bronchial asthma of mild to moderate severity.
Materials and Methods:
Fifty cases of bronchial asthma (Forced Expiratory Volume in one second (FEV1) > 70%) were studied for 12 weeks. Patients were allocated to two groups: group A and group B (control group). Patients in group A were treated with breathing exercises (deep breathing,Brahmari, and Omkara, etc.) for 20 minutes twice daily for a period of 12 weeks. Patients were trained to perform Omkara at high pitch (forceful) with prolonged exhalation as compared to normal Omkara. Group B was treated with meditation for 20 minutes twice daily for a period of 12 weeks. Subjective assessment, FEV1%, and Peak Expiratory Flow Rate (PEFR) were done in each case initially and after 12 weeks.
After 12 weeks, group A subjects had significant improvement in symptoms, FEV1, and PEFR as compared to group B subjects.
Breathing exercises (pranayama), mainly expiratory exercises, improved lung function subjectively and objectively and should be regular part of therapy.
Bronchial asthma; expiratory breathing exercises; FEV1; PEFR
With a significant number of women belonging to the status of menopause and beyond, it is imperative to plan a comprehensive health program for them, including lifestyle modifications. Exercise is an integral part of the strategy. The benefits are many, most important being maintenance of muscle mass and thereby the bone mass and strength. The exercise program for postmenopausal women should include the endurance exercise (aerobic), strength exercise and balance exercise; it should aim for two hours and 30 minutes of moderate aerobic activity each week. Every woman should be aware of her target heart rate range and should track the intensity of exercise employing the talk test. Other deep breathing, yoga and stretching exercises can help to manage the stress of life and menopause-related symptoms. Exercises for women with osteoporosis should not include high impact aerobics or activities in which a fall is likely. The women and the treating medical practitioner should also be aware of the warning symptoms and contraindications regarding exercise prescription in women beyond menopause. The role of exercise in hot flashes, however, remains inconclusive. Overall, exercising beyond menopause is the only noncontroversial and beneficial aspect of lifestyle modification and must be opted by all.
Bone health; exercise; menopause
This study evaluated the impact of a breathing awareness meditation (BAM) program on ambulatory blood pressure and sodium handling in African American adolescents with high-normal systolic blood pressure (SBP) levels.
Design and Methods
Following three consecutive days of SBP screenings, 66 eligible ninth graders were randomly assigned by school to either BAM (n=20) or health education control (n=46) groups. The BAM group engaged in 10-minute BAM sessions at school and at home each day for three months. Teachers conducted sessions at school during health classes. Before and after the intervention, overnight urine samples were collected, and ambulatory SBP, diastolic blood pressure, and heart rate were recorded periodically for 24 hours.
Significant changes before and after the intervention were observed between BAM and control groups for SBP during school hours (−4.7 vs .9 mm Hg, P<.05), SBP at night (−4.8 vs −.6 mm Hg, P<.01), and heart rate during school hours (−6.7 vs −2.3 bpm, P<.02), adjusted for their respective pre-intervention levels. The overnight urinary sodium excretion rate decreased in the BAM group but increased in the control group (−.3±4.9 vs 1.1±4.0 mEq/hour, P<.03).
These findings demonstrate the potential beneficial impact of BAM taught by school health teachers on blood pressure control in the natural environment in African American youth at risk for development of hypertension.
Adolescents; Blood Pressure Monitoring; Meditation; Hypertension; Sodium Handling; African American; Clinical Trials
To determine the immediate effects of a combined form of tai chi/yoga.
38 adults participated in a 20-minute tai chi/yoga class. The session was comprised of standing tai chi movements, balancing poses and a short tai chi form and 10 minutes of standing, sitting and lying down yoga poses.
Main outcome measures
The pre- and post- tai chi/ yoga effects were assessed using the State Anxiety Inventory (STAI), EKG, EEG and math computations.
Heartrate increased during the session, as would be expected for this moderate intensity exercise. Changes from pre to post session assessments suggested increased relaxation including decreased anxiety and a trend for increased EEG theta activity.
The increased relaxation may have contributed to the increased speed and accuracy noted on math computations following the tai chi/yoga class.
Stress is often associated with an increased occurrence of autonomic, cardiovascular, and immune system pathology. This study was done to evaluate the impact of stress on psychological, physiological parameters, and immune system during medical term -academic examination and the effect of yoga practices on the same.
Materials and Methods:
The study was carried out on sixty first-year MBBS students randomly assigned to yoga group and control group (30 each). The yoga group underwent integrated yoga practices for 35 minutes daily in the presence of trained yoga teacher for 12 weeks. Control group did not undergo any kind of yoga practice or stress management. Physiological parameters like heart rate, respiratory rate, and blood pressure were measured. Global Assessment of Recent Stress Scale and Spielbergers State Anxiety score were assessed at baseline and during the examination. Serum cortisol levels, IL-4, and IFN-γ levels were determined by enzyme-linked immunosorbent assay technique.
In the yoga group, no significant difference was observed in physiological parameters during the examination stress, whereas in the control group, a significant increase was observed. Likewise, the indicators of psychological stress showed highly significant difference in control group compared with significant difference in yoga group. During the examination, the increase in serum cortical and decrease in serum IFN-γ in yoga group was less significant (P<0.01) than in the control group (P<0.001). Both the groups demonstrated an increase in serum IL-4 levels, the changes being insignificant for the duration of the study.
Yoga resists the autonomic changes and impairment of cellular immunity seen in examination stress.
Cell-mediated immune responses; IL-4; IFN-γ; state anxiety score; stress; yoga
Diaphragmatic breathing is relaxing and therapeutic, reduces stress, and is a fundamental procedure of Pranayama Yoga, Zen, transcendental meditation and other meditation practices. Analysis of oxidative stress levels in people who meditate indicated that meditation correlates with lower oxidative stress levels, lower cortisol levels and higher melatonin levels. It is known that cortisol inhibits enzymes responsible for the antioxidant activity of cells and that melatonin is a strong antioxidant; therefore, in this study, we investigated the effects of diaphragmatic breathing on exercise-induced oxidative stress and the putative role of cortisol and melatonin hormones in this stress pathway. We monitored 16 athletes during an exhaustive training session. After the exercise, athletes were divided in two equivalent groups of eight subjects. Subjects of the studied group spent 1 h relaxing performing diaphragmatic breathing and concentrating on their breath in a quiet place. The other eight subjects, representing the control group, spent the same time sitting in an equivalent quite place. Results demonstrate that relaxation induced by diaphragmatic breathing increases the antioxidant defense status in athletes after exhaustive exercise. These effects correlate with the concomitant decrease in cortisol and the increase in melatonin. The consequence is a lower level of oxidative stress, which suggests that an appropriate diaphragmatic breathing could protect athletes from long-term adverse effects of free radicals.
Tidal volume can be measured by recording the change in impedance of the thorax caused by breathing. Thus breathing can be recorded quantitatively from two electrodes placed on each side of the chest. The method is especially useful in breathless patients and studies of breathing patterns during sleep. A patient with a long circulation time due to left ventricular failure had periodic breathing both awake and asleep. When asleep the respiratory minute volume was considerably reduced, and there were long apnoeic periods. This was associated with a rise in mean right atrial pressure until the patient woke with an attack of paroxysmal dyspnoea. The right atrial pressure dropped to normal when the patient breathed more regularly. Anoxia probably caused the rise in right atrial pressure. Periodic breathing disappeared when the circulation time shortened after treatment of the heart failure. The possible mechanism of these changes is discussed.
In earlier studies uninostril yoga breathing was shown to influence the activity of the cerebral hemispheres differently, based on (i) auditory evoked potentials recorded from bilateral scalp sites, and (ii) performance in hemisphere-specific tasks. But change in P300 (event-related potential generated when subjects attend to and discriminate between stimuli) from bilateral scalp sites when subjects were practicing uni- and alternate-nostril breathing are yet to be explored.
The present study was designed to determine whether or not immediately after uninostril or alternate nostril yoga breathing there would be a change in the ability to pay attention to a given stimulus.
Materials and Methods:
Twenty-nine healthy male volunteers, with ages between 20 and 45 years were randomly allocated to five sessions, viz., (i) right-, (ii) left-, (iii) alternate-nostril yoga breathing, (iv) breath awareness and (v) no intervention, each for 45 min on separate days. The P300 event related potential was recorded using an auditory oddball paradigm from sites on the left (C3) and right (C4), referenced to linked earlobes, before and after each session.
Post-hoc analysis with Bonferroni adjustment showed that the P300 peak latency was significantly lower at C3 compared to that at C4, following right nostril yoga breathing (P<0.05).
These results suggest that right nostril yoga breathing facilitates the activity of contralateral (left) hemisphere, in the performance of the P300 task.
Contralateral changes; P300; uni-nostril yoga breathing
Previous studies have indicated that Yoga exercise has a positive effect on reducing blood pressure and heart rate. However, no randomized controlled studies to date have investigated its effects on arterial compliance. The purpose of this study was to investigate the effects of an 8-month Yoga intervention on arterial compliance and muscle strength in normal premenopausal women 35-50 years of age. Thirty-four women were randomly assigned either to a Yoga exercise group (YE, n = 16) or a control group (CON, n = 18). Participants in YE group performed 60 minutes of an Ashtanga Yoga series 2 times/week with one day between sessions for 8 months. Each Yoga session consisted of 15 minutes of warm-up exercises, 35 minutes of Ashtanga Yoga postures and 10 minutes of cool-down with relaxation; and the session intensity was progressively increased during the 8 months. Participants in CON were encouraged to maintain their normal daily lifestyles monitored by the bone-specific physical activity questionnaire at 2 month intervals for 8 months. Arterial compliance (pulse contour analysis) and muscle strength (1 Repetition Maximum) were assessed at baseline and after the intervention. Arterial compliance of the large and small arteries was not affected by the 8 month Yoga training (p > 0.05). Also, there were no significant (p > 0.05) group, time, or group × time interaction effects for cardiovascular variables. YE group significantly (p < 0.01) improved leg press muscle strength compared to CON (11.4% vs. -6.5%). Eight months of Ashtanga Yoga training was beneficial for improving leg press strength, but not arterial compliance in premenopausal women.
The 8 month Yoga training did not affect arterial compliance of the large and small arteries.
None of the cardiovascular variables were changed by the Yoga intervention.
Isotonic muscle strength was not altered by the Yoga intervention, with the exception of leg press.
Ashtanga Yoga; arterial stiffness; blood pressure
To test whether rhythmic formulas such as the rosary and yoga mantras can synchronise and reinforce inherent cardiovascular rhythms and modify baroreflex sensitivity.
Comparison of effects of recitation of the Ave Maria (in Latin) or of a mantra, during spontaneous and metronome controlled breathing, on breathing rate and on spontaneous oscillations in RR interval, and on blood pressure and cerebral circulation.
Florence and Pavia, Italy.
23 healthy adults.
Main outcome measures
Breathing rate, regularity of breathing, baroreflex sensitivity, frequency of cardiovascular oscillations.
Both prayer and mantra caused striking, powerful, and synchronous increases in existing cardiovascular rhythms when recited six times a minute. Baroreflex sensitivity also increased significantly, from 9.5 (SD 4.6) to 11.5 (4.9) ms/mm Hg, P<0.05.
Rhythm formulas that involve breathing at six breaths per minute induce favourable psychological and possibly physiological effects.
What is already known on this topicReduced heart rate variability and baroreflex sensitivity are powerful and independent predictors of poor prognosis in heart diseaseSlow breathing enhances heart rate variability and baroreflex sensitivity by synchronising inherent cardiovascular rhythmsWhat this study addsRecitation of the rosary, and also of yoga mantras, slowed respiration to almost exactly 6/min, and enhanced heart rate variability and baroreflex sensitivityThe rosary might be viewed as a health practice as well as a religious practice
An association has been reported between the dominant nostril through which we breathe and the cerebral hemisphere found to be active.
To understand the association between the nostril dominant at rest and the performance in a cancellation task using verbal information–a left hemisphere task.
Materials and Methods:
Two hundred eighty-nine normal, healthy volunteers attending a one week nonresidential yoga camp were assessed in a single 30 minute period. Nostril dominance was assessed using a standard method. After this, participants were given the letter cancellation task and nostril dominance was again checked. For each participant, the numbers of letters that had been left out and wrongly cancelled as well as total errors were assessed. The Mann-Whitney u test and Chi-Square test were used to assess whether there was a significant difference in cancellation task performance between right and left nostril-dominant persons.
There was no statistically significant difference between right and left nostril-dominant participants.
The present results do not support previous findings of contralateral cerebral hemisphere improvement with breathing through a specific nostril.
Left cerebral hemisphere; letter cancellation task; nostril dominance
Twelve asthmatic adults each completed two six minute treadmill runs separated by an interval of 20 minutes. Running speed was constant for each subject, and inspired air temperature averaged 5.5 degrees C (SD 1.5 degree) for both tests. Total minute ventilation and total respiratory heat loss showed no significant difference between the two runs. Forced expiratory volume in one second (FEV1) was measured before exercise and at five minute intervals throughout the recovery periods, during which subjects breathed room air at an average temperature of 17.8 degrees C (1.8 degree). Reduction in FEV1 from pre-exercise readings averaged 39.3% (13.3%) for the first run and 11.5% (7.3%) for the second. On another day the subjects underwent an identical procedure except that the first exercise period was performed with the saturated inspirate at 37.3 degrees C (1.7 degree). This run produced a mean FEV1 reduction of only 3.1% (7.3%). The ensuing run, during which the inspiratory temperature averaged 6.0 degrees C (2.0 degrees), led to a mean fall in FEV1 of 37.3% (17.3%). This was not significantly different from the value recorded for the first of the paired runs with cool air. We therefore have been unable to confirm that exercise with warm humid inspirate may induce refractoriness to exercise induced asthma. Our data are compatible with the theory that refractoriness may be due to depletion of mediators during an initial exercise induced asthma attack.
The metabolic rate is an indicator of autonomic activity. Reduced sympathetic arousal probably resulting in hypometabolic states has been reported in several yogic studies.
The main objective of this study was to assess the effect of yoga training on diurnal metabolic rates in yoga practitioners at two different times of the day (at 6 a.m. and 9 p.m.).
Materials and Methods:
Eighty eight healthy volunteers were selected and their metabolic rates assessed at 6 a.m. and 9 p.m. using an indirect calorimeter at a yoga school in Bangalore, India. Results and conclusions: The results show that the average metabolic rate of the yoga group was 12% lower than that of the non-yoga group (P < 0.001) measured at 9 p.m. and 16% lower at 6 a.m. (P < 0.001). The 9 p.m. metabolic rates of the yoga group were almost equal to their predicted basal metabolic rates (BMRs) whereas the metabolic rate was significantly higher than the predicted BMR for the non-yoga group. The 6 a.m. metabolic rate was comparable to their predicted BMR in the non-yoga group whereas it was much lower in the yoga group (P < 0.001). The lower metabolic rates in the yoga group at 6 a.m. and 9 p.m. may be due to coping strategies for day-to-day stress, decreased sympathetic nervous system activity and probably, a stable autonomic nervous system response (to different stressors) achieved due to training in yoga.
Basal Metabolic Rate (BMR); decreased arousal response; yoga; yoga training
Extrapolation from post-exercise measurements has been used to estimate respiratory and blood gas parameters during exercise. This may not be accurate in exercise with reduced breathing frequency (RBF), since spontaneous breathing usually follows exercise. This study was performed to ascertain whether measurement of oxygen saturation and blood gases immediately after exercise accurately reflected their values during exercise with RBF. Eight healthy male subjects performed an incremental cycling test with RBF at 10 breaths per minute. A constant load test with RBF (B10) was then performed to exhaustion at the peak power output obtained during the incremental test. Finally, the subjects repeated the constant load test with spontaneous breathing (SB) using the same protocol as B10. Pulmonary ventilation (VE), end-tidal oxygen (PETO2), and carbon dioxide pressures (PETCO2) and oxygen saturation (SaO2) were measured during both constant load tests. The partial pressures of oxygen (PO2) and carbon dioxide (PCO2) in capillary blood were measured during the last minute of exercise, immediately following exercise and during the third minute of recovery. At the end of exercise RBF resulted in lower PETO2, SaO2 and PO2, and higher PETCO2 and PCO2 when compared to spontaneous breathing during exercise. Lower SaO2 and PETO2 were detected only for the first 16s and 20s of recovery after B10 compared to the corresponding period in SB. There were no significant differences in PO2 between SB and B10 measured immediately after the exercise. During recovery from exercise, PETCO2 remained elevated for the first 120s in the B10 trial. There were also significant differences between SB and B10 in PCO2 immediately after exercise. We conclude that RBF during high intensity exercise results in hypoxia; however, due to post-exercise hyperpnoea, measurements of blood gas parameters taken 15s after cessation of exercise did not reflect the changes in PO2 and SaO2 seen during exercise.
In some sports, the environment is inappropriate for direct measurement of respiratory and blood gas parameters during exercise. To overcome this problem, extrapolation from post-exercise measurements has often been used to estimate changes in respiratory and blood gas parameters during exercise.
The possibility of hypoxia and hypercapnia during exercise with reduced breathing frequency has been tested by measuring capillary blood sampled after the exercise.
Reduced breathing frequency during high intensity exercise results in hypoxia; however, due to marked post-exercise hyperventilation, measurements of blood gas parameters taken 15 s after the cessation of exercise did not yield any changes in these parameters.
Despite hyperventilation during recovery, hypercapnia could be detected by measuring blood gas parameters within 15 s after the exercise with reduced breathing frequency.
Constant load test; reduced breathing frequency; recovery; respiratory parameters; oxygen saturation; blood gas
The aim of this study was to observe the effect comprehensive yogic breathing (Sudarshan Kriya Yoga [SKY] and Pranayam) had on cardiac autonomic functions in patients with diabetes.
Materials and Methods:
This is a prospective randomized controlled intervention trial. Cardiac autonomic functions were assessed in 64 diabetics. Patients were randomized into two groups, one group receiving standard therapy for diabetes and the other group receiving standard therapy for diabetes and comprehensive yogic breathing program. Standard therapy included dietary advice, brisk walking for 45 min daily, and administration of oral antidiabetic drugs. Comprehensive yogic breathing program was introduced to the participants through a course of 12 h spread over 3 days. It was an interactive session in which SKY, a rhythmic cyclical breathing, preceded by Pranayam is taught under the guidance of a certified teacher. Cardiac autonomic function tests were done before and after 6 months of intervention.
In the intervention group, after practicing the breathing techniques for 6 months, the improvement in sympathetic functions was statistically significant (P 0.04). The change in sympathetic functions in the standard therapy group was not significant (P 0.75). Parasympathetic functions did not show any significant change in either group. When both parasympathetic and sympathetic cardiac autonomic functions were considered, there was a trend toward improvement in patients following comprehensive yogic breathing program (P 0.06). In the standard therapy group, no change in cardiac autonomic functions was noted (P 0.99).
Cardiac autonomic functions improved in patients with diabetes on standard treatment who followed the comprehensive yogic breathing program compared to patients who were on standard therapy alone.
Cardiac autonomic function; comprehensive yogic breathing; diabetes mellitus
Background. Meditation practices are associated with a reduction in adrenergic activity that may benefit patients with severe cardiac arrhythmias. This paper describes the design and methods of a pilot study testing the feasibility of a phone-delivered mindfulness-based intervention (MBI) for treatment of anxiety in patients with implantable cardioverter defibrillators (ICDs). Design and Methods. Consecutive, clinically stable outpatients (n = 52) will be screened for study eligibility within a month of an ICD-related procedure or ICD shock and will be randomly assigned to MBI or to usual care. MBI patients will receive eight weekly individual phone sessions based on two mindfulness practices (awareness of breath and body scan) plus home practice with a CD for 20 minutes daily. Patients assigned to usual care will be offered the standard care planned by the hospital. Assessments will occur at baseline and at the completion of the intervention (between 9 and 12 weeks after randomization). The primary study outcome is feasibility; secondary outcomes include anxiety, mindfulness, and number of administered shocks during the intervention period. Conclusions. If proven feasible and effective, phone-delivered mindfulness-based interventions could improve psychological distress in ICD outpatients with serious cardiovascular conditions.
The present study assessed the effects of awareness at encoding on off-line learning during sleep. A new framework is suggested according to which two aspects of awareness are distinguished: awareness of task information, and awareness of task processing. The number reduction task (NRT) was employed because it has two levels of organization, an overt one based on explicit knowledge of task instructions, and a covert one based on hidden abstract regularities of task structure (implicit knowledge). Each level can be processed consciously (explicitly) or non-consciously (implicitly). Different performance parameters were defined to evaluate changes between two sessions for each of the four conditions of awareness arising from whether explicit or implicit task information was processed explicitly or implicitly. In two groups of subjects, the interval between the pre-sleep and post-sleep sessions was filled either with early-night sleep, rich in slow wave sleep (SWS), or late-night sleep, rich in rapid eye movement (REM) sleep. Results show that implicit processing of explicit information was improved in the post-sleep relative to the pre-sleep session only in the early-night group. Independently of sleep stage, changes between sessions occurred for explicit processing of implicit information only in those subjects who gained insight into the task regularity after sleep. It is concluded that SWS but not REM sleep specifically supports gains in computational skills for the processing of information that was accessible by consciousness before sleep.
memory consolidation; sleep; implicit knowledge; explicit knowledge; implicit processing; explicit processing; insight