Slowing Breathing Rate
from http://www.bmj.com/cgi/content/full/323/7327/1446
Effect of rosary prayer and yoga mantras on autonomic cardiovascular rhythms: comparative study
Luciano Bernardi a Dipartimento di Medicina Interna,
University of Pavia, 27100 Pavia, Italy, b Department of
Cardiovascular Medicine, John Radcliffe Hospital, Oxford OX3 9DU, c Dipartimento
di Medicina Interna, Unitá Ospedaliera S Maria Nuova, 50100 Florence, Italy,
d Department of Cardiology, University of Gdansk, 80-211 Gdansk,
Poland
Correspondence to: L Bernardi
lbern1ps@unipv.it
Abstract
Objective: To test whether rhythmic formulas such as the rosary and yoga mantras can synchronize and reinforce inherent cardiovascular rhythms and modify baroreflex sensitivity.
Design: 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.
Setting: Florence and Pavia, Italy.
Participants: 23 healthy adults.
Main outcome measures: Breathing rate, regularity of breathing, baroreflex sensitivity, frequency of cardiovascular oscillations.
Results: 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.
Conclusion: Rhythm formulas that involve breathing at six
breaths per minute induce favorable psychological and possibly
physiological
effects.
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What is
already known on this topic What this
study adds |
We serendipitously discovered that reciting the Ave Maria prayer and yoga mantras enhances and synchronizes inherent cardiovascular rhythms because it slows respiration to almost exactly six respirations per minute, which is essentially the same timing as that of endogenous circulatory rhythms.
Healthy animals and humans show rhythmic fluctuations in blood pressure and heart rate as a result of autonomic control systems that are influenced by respiration, arousal, and activity. More than a century ago Mayer described a 10 second cycle in blood pressure (6/min) that is related to both vagal and sympathetic activity.1 This is thought to be generated either by a central nervous oscillator in the medulla oblongata or by the imperfect feedback control caused by one or other, or both, of two reflexes-the relatively slow baroreflex sympathetic response time and the faster vagal response to respiratory changes in blood pressure.2-4
These rhythms, which can be conveniently analyzed by spectral analysis of cardiovascular fluctuations, have recently gained considerable clinical importance. It has been shown that reduction in their responses is an independent predictor of increased future risk after a recent heart attack,5 or in heart failure.6 A slow respiratory rate (6/min) has generally favorable effects on cardiovascular and respiratory function and increases respiratory sinus arrhythmia, the arterial baroreflex,7 oxygenation of the blood, and exercise tolerance.8 In chronic heart failure it also reduces the exaggerated sensitivity of the respiratory chemoreflex, and improves irregular breathing. 8 9 Slow respiration may reduce the deleterious effects of myocardial ischaemia, and, in addition, it increases calmness and wellbeing.9 These effects result from, at least in part, synchronization of respiratory and cardiovascular central rhythms. A respiratory rate of around 6/min coincides with and thus augments the 10 second (6/min) Mayer waves, and so increases the power of vagal respiratory sinus arrhythmia. The favorable effects of slowed breathing may be mediated, at least partly, by a modulation of autonomic activity at both central and peripheral (baroreflex) levels.
In the course of experiments in which we used power spectrum analysis to track the different effects on sympathovagal balance produced by silent compared with spoken reading, or silent compared with spoken mental arithmetic, we used the rosary as a less "arousing" control condition. The rosary is a repetition 50 times of the Ave Maria, the whole 50 repeated three times. Each cycle, recited half by the priest and half by the congregation, is-in the original Latin-normally completed within a single slow respiration. We were surprised to find that each cycle (and break) of the Ave Maria (both "priest's" and "congregation's" parts, unrehearsed) took almost exactly 10 seconds.
We believe that the rosary may have
partly evolved because it synchronized with the inherent cardiovascular
(Mayer) rhythms, and thus gave a feeling of wellbeing, and
perhaps an increased responsiveness to the religious
message.
Methods
In 23 healthy subjects (16 men, 7 women;
mean age 34 (SD 8) years, weight 72.7 (3.2) kg, height 176 (1) cm) we
recorded the
electrocardiogram, respiration, blood pressure continuously and
non-invasively at the wrist (Pilot Mod, Colin Corporation, San
Antonio, TX), and midcerebral arterial flow velocity by transcranial
Doppler ultrasonography with a 2 MHz probe (Multidop S, DWL, Sipplingen,
Germany). We recorded spontaneous breathing (3 minute sequences)
and controlled breathing (6 minute sequences) during free talking
and during recitation of the Ave Maria in Latin, with one subject
reciting the priest's part and another the response (no instruction
was given as to time to be taken); and during six minutes of controlled
breathing. Recordings were also obtained during repetition of a
typical yoga mantra "om-mani-padme-om."
The subjects studied had no previous experience of yoga but in the days before the study they were briefly instructed how to recite the mantra by a yoga teacher unaware of the aim of the study. Briefly, they were instructed to repeat the mantra with an "alive," resonant voice; to listen to the sound produced and to let it flow freely; and then to complete the expiration comfortably after the end of the mantra and to pause if a rest was needed before the next cycle. No instruction was given as to time to be taken or any particular singing pitch.
Reciting the mantra stabilizes the respiratory rate
The recordings were obtained in random order, except for the controlled breathing, which was always performed last. To control breathing we used an electronic metronome together with a visual signal, as in previous studies.10 The data were acquired on line at the sampling rate of 500Hz/channel to obtain the sequences of RR intervals, and systolic and diastolic blood pressures. By spectral analysis, we measured the amplitude and the frequency of the main fluctuations in respiration and in all the other signals, which were compared in the various conditions. In addition, using a technique derived from spectral analysis, we measured the gain of the spontaneous baroreflex by dividing the amplitudes of the oscillations in RR interval by the corresponding amplitudes of oscillations in systolic blood pressure. 3 4 Finally, the regularity of breathing was assessed by the coefficient of variation (standard deviation/mean×100) of the respiratory rate, during each condition and for each subject.
Priest: "Ave Maria, gratia plena, Dominus tecum, benedicta tui mulieribus et benedictus fructus ventris tui Jesus"
Congregation:
"Sancta Maria, Mater Dei, ora pro nobis
peccatoribus, nunc et in hora mortis nostrae, Amen"
Results
Both the Ave Maria and the yoga mantra had similar effects, slowing respiration to around 6/min and thus having a marked effect on synchronization and also increased variability in all cardiovascular rhythms (table). This was seen not only in the respiratory signals but also in the RR interval, systolic and diastolic blood pressures, and in the transcranial blood flow signal. The spontaneous respiratory rate was 14.1 (4.8) per minute during spontaneous breathing; it slowed down during free talking, and it slowed down further during the recitation of the Ave Maria and of the mantra, in both cases to close to the 6/min (10 s period) Mayer rhythm.
Respiratory frequency and variability, and sensitivity of baroreflex, in 23 healthy adults. Values are means (SDs) |
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Free talking reduced the respiratory rate more irregularly (table). The breathing was markedly more regular during slow breathing, the Ave Maria, and the mantra, whereas it was less regular during free talking than during spontaneous breathing (table). Remarkably, the regularity of breathing seen during recitation of the Ave Maria or of the mantra was similar to regularity during controlled breathing at 6/min, indicating that these methods could stabilize the respiratory rate as effectively as precisely timed control.
The spectral peaks of respiration and
of all cardiovascular signals were synchronized during the Ave Maria and the
mantra sequences, as they occurred at the same frequency. In
addition, the spectral peak of respiration was narrower during
the Ave Maria sequence than during spontaneous breathing and free
talking, again as a consequence of more regular breathing (fig
1, fig 2). This increased modulation in
cardiovascular rhythms influenced the cardiovascular control
mechanisms: the arterial baroreflex sensitivity increased on
change from spontaneous breathing to controlled slow breathing at
6/min and from free talking to the Ave Maria, or from free
talking to the mantra (table).
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Discussion
The timing of the Ave Maria and the yoga mantra, as normally spoken in the original language, turned out to be close to 10 seconds for each cycle. This frequency (6/min) coincides with the subjects' spontaneous Mayer wave frequency and thus enhanced this cardiovascular oscillation by synchronizing sympathetic and vagal outflow. This even resulted in rhythmic fluctuations in cerebral blood flow, which might directly influence central nervous oscillations.11
Normal talking has the effect of modulating the breathing rate and in general reducing it, though it remains irregular. If the talking is rhythmic then respiration stabilizes to a constant frequency. If this coincides with spontaneous cardiovascular rhythms, these rhythms are enhanced. Repeated training to slow down breathing also reduces the spontaneous breathing rate, and thus may have more than just short term effects.7-9 We have shown that recitation of the prayer or the mantra has a similar effect to that of slow breathing,7 increasing the arterial baroreflex, which is a favorable prognostic factor in long term studies in cardiac patients. 5 6
Culturally distinct
practices?
Is there anything linking these two geographically and culturally
distant practices? Surprisingly, there is historical evidence for
a link. The rosary was introduced to Europe by the crusaders, who
took it from the Arabs, who in turn took it from Tibetan monks
and the yoga masters of India.12 This supports
the hypothesis that the similar characteristics and effects of
these mantras and of the rosary may not be a simple coincidence.
Owing to the very large number of
repetitions of the same prayer, the rosary is unique among prayers of the
Christian religion. The rhythm necessarily imposed by these
repetitions induces a fixed respiratory rate at a predetermined
frequency. In times when stopwatches and metronomes had still to
be invented, a rhythmic formula was the easiest way to keep a
reasonably accurate timing in the range of several seconds per
breath, and thus a good way to learn to slow respiration to a
given rate, without the need to concentrate on the respiration
itself (body consciousness was not encouraged in the Christian
culture of the Middle Ages). There are thus remarkable
similarities in the two practices (duration and number of
repetitions) and in their cardiovascular effects. The historical
circumstances that brought the rosary to Europe also suggest that
these similarities were not just coincidence. This practice
introduced-consciously
or not-a
new and previously unrecognised element of oriental health
practice into Western culture. The rosary might be viewed as a
health practice as well as a religious practice.
Acknowledgments
Contributors: LB, GB, SC, LF, and JW collected the data and LB and JW analysed them. All authors contributed to the concept and design of the study and to the writing of the manuscript.
Footnotes
Funding: None.
Competing interests: None declared.
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