Blood Pressure Reduction by Yoga

8/8/2019 Blood Pressure Reduction by Yoga

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Blood Pressure Reduction

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Blood pressure reduction is another well-documented effect of Yoga. Herbert Benson and others

have shown that meditation and Yoga postures are effective means of sustaining a lowered

systolic and diastolic pressure, provided that the practice of Yoga is consistent.

The physiologic effects of Yoga are mediated through at least two different pathways. The

intrafusal muscle fibersthe annulospiral and flower spray endings that we have just discussed

help moderate blood pressure through reduced contraction of substantial areas of muscular

capillary beds, thus producing a gross reduction of the pressure in those capillary beds because

of reduced muscle tone.

A second, totally different pathway involves the hypothalamic regulation of stressor (and tensor)

hormonal influences that appear to be determined by the more psychologic effects of Yoga. In

addition to muscle relaxation, and partially because of it, a calm comes over the Yoga

practitioner. This has been widely noted to increase the production of alpha waves in cortical and

subcortical recordings (29). The respiratory rate and airway resistance are also reduced (30).


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Figure 6.12Reciprocal neuroendocrine relationships of the pituitary (more...)

Figure 6.12

Reciprocal neuroendocrine relationships of the pituitary are illustrated by higher

centers influence on the hypothalamic portal vessels hormonal content, which

individually regulate gonadal, thyroid, and adrenal secretions, which in turn


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feed back to the hypothalamus and higher centers. Nervous control of the

posterior pituitary through supraoptic and paraventricular pathways, and from

spinal preganglion neurons through splanchnic nerves to the adrenal medulla

are also pictured. (Revised from Raisman G. An urge to explain the

incomprehensible: Geoffrey Harris and the discovery of the neural control of

the pituitary gland. In: Cowan WM, Shooter EM, Stevens CF, Thompson RF

(eds.),Ann Rev Neuroscience 1997; 20:53366l.)

These effects are the principal causes of blood pressure reduction. Their beneficial influence is

also seen in adjustments of blood chemistry, cutaneous blood vessels, and cardiac rate and

output. The primary changes that Yoga brings about in the muscles, brain, and lungs mediate

these secondary effects on blood chemistry, cutaneous circulation, and blood pressure through

the cerebral cortex, hypothalamus, pituitary, and adrenal glands (see Figure 6.12

) (30).


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It is important to consider which poses are most likely to produce and sustain lowered blood

pressure in the hypertensive population, and which may dangerously lower systolic or diastolic

pressure in patients that are borderline hypotensive.

Forward Bending Poses and Blood Pressure

Individual poses often have strong specific effects, for physiologic and anatomic reasons. The

forward bends (Figure 6.2) are a group of poses with such effects. Many such poses stretch the

hamstrings, flexor calf muscles, gluteus maximus, adductors, and longitudinal muscles of the

dorsal abdomen, thorax, and neck. These latter include the serratus posterior inferior, quadratus

lumborum, multifidus, iliocostalis and transversalis muscles, and a large number of similar

muscles in similar regions.

Figure 6.13


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Figure 6.13

Consider the extreme forward stretch, Paschimotanasana, the ancient progenitor of Williams

flexion exercises, scores of related poses from Yoga, and countless maneuvers in other

disciplines (see Figure 6.13 ).

Forward stretching poses generally prompt people to observe how stiff they are. The positions

can be painful; the pain is directly proportional to how much the practitioner chooses to stretch.

Because Yoga is not about the mortification of the flesh, many Yoga teachers encourage pupils to

work to make the poses as painless as possible. Continued practice is certainly one way to do

this, because continued practice greatly lessens the pain, as the muscles lengthen and the

nervous system perfects the means of relaxing them. In fact, Paschimottanasana is analogous to

the Jendrassik maneuver, which, in the short run, heightens the H-reflex, but in the long-term,

actually diminishes it (31). However, when asked to stay in Paschimottanasana for more than 10

or 15 minutes, the fact that it will be less painful three years hence is little consolation!


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Yogas ingenious poses have been refined over thousands of years and by millions of

practitioners bound only by their own best judgment. The absence of a central controlling

hierarchy in Yoga has a Darwinian impetus toward excellence, although it may be difficult to

appreciate this refinement in the face of the perceived simplicity of each pose.

To limit or reduce pain in learning forward bending Yoga poses (particularly Paschimottanasana),

keep the knees straight. Bending the knees destroys the effects of the stretch reflex and sets up

agonistantagonist excitation instead of the relaxation response that is sought.

Stooping (kyphosis) of the thoracic and cervical spine to bring the head down closer to the

outstretched leg(s) is strongly discouraged. Instead, the goal is to bring the lower lumbar spine

as close to the outstretched thighs and knees as possible, maintaining the normal anatomic and

postural architecture of the torso, neck, and shoulders.

If a pose is practiced within these defining parameters, then significant benefits accrue. To

reduce immediate pain, relax the leg and lower back muscles that are stretched by the pose.

This process is promoted by both conscious and instinctual means. The advantages start with the

relaxation response and go well beyond it. As the abdomen comes closer to the thighs, pressure

on the splanchnic pool relocates a meaningful proportion of blood volume. At first, this increases

perceived volume and pressure at the carotid sinus and baroreceptors in the proximal aorta,

directly lowering blood pressure through peripheral arterial smooth muscle dilatation and

inotropic cardiac changes. Cardiac functional output and circulatory system capacity are two of

the major components determining blood pressure.

After a short time, this folding over of the abdomen on the thighs reduces venous flow in the

low-pressure femoral veins proximal to the foramen ovale, while having less impact on the

higher-pressure iliac and femoral arterial systems. As a secondary result, there is some pooling

of blood in the legs, reducing effective blood volume, the third component in hypertension.

Both the anterior (parasympathetic) and posterior (sympathetic) hypothalamus are regulated by

interoceptors responding to blood pressure, water, and oxygen concentrations and to external


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factors such as heat, acceleration, and noise levels. It has been convincingly shown that both

parts of the hypothalamus also respond to cognitive events such as the perception of danger,

relaxation and safety, imagination, and intentions (32).

Almost all the forward bend poses must be sustained for one minute, after a variable period of

training. However, many practitioners hold Paschimottanasa, the most symmetrical and restful of

forward bends, for 15 to 30 minutes on a regular basis.

Other conditions benefiting from the anatomical stretch of these poses include arthritis,

restricted range of motion of the hips, and piriformis syndrome. Whether patients having dorsal

kyphosis, early forms of ankylosing spondylitis, or scoliosis receive any benefit is still arguable.

However, the isometric stretch ofPaschimottasana is clearly of benefit in arthritis of any

etiology, and in piriformis syndrome, so long as the sciatic compression is not caused by ventral

piriformis muscle scarring.

Figure 6.14


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Figure 6.14

The calming effect of forward bends can be put to simultaneous use in head trauma (and other

impulsive) patients where lowering blood pressure may be useful. Combined with increasing

range of motion and hamstring length in patients emerging from the lower reaches of the

Glasgow scale, with or without heterotopic ossification, the Viparita karani(see Figure 6.14

) is a modified forward bend that

combines a modest lumbar flexion with partial inversion that most patients can easily tolerate. It

is extremely pleasant to retain for up to 10 minutes after a few trials of shorter duration. Viparita

karanibridges the gap between forward bends and inverted poses, and is a good introduction to

them. Viparita karanihas been used for this purpose in patients incapable of the poses described

so far.


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Figure 6.15There is no substitute for a personal relationship (more...)

Figure 6.15

There is no substitute for a personal relationship with the expert who can vary

the pose according to ones changing needs.


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Figure 6.16Another variation ofViparita karanisuitable for (more...)

Figure 6.16


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Another variation ofViparita karanisuitable for relieving headache.

Figure 6.17At the shoulderstand part of the Viparita karani(more...)

Figure 6.17

At the shoulderstand part of the Viparita karanispectrum.

Viparita karaniis best done with a helper, at least at first. After setting up a gradual slope of

pillows against a wall, the patient lies supine near it, on a blanket or carpeted floor (see Figure


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6.15 ). The helper directs the patient to lift

her legs toward vertical, using her arms to inch over onto the pillows. A more acute angle

between the thighs and torso is gradually sought over time. At first, the idea is to have some hip

flexion and some inversion. The pose can be made more difficult (and more effective) by

lowering the slope of pillows (for greater hip flexion, approaching a forward bend) or by raising

the slope, which creates more elevation and approaches the shoulder stand, headstand, and


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other inverted poses (see Figures 6.16 and 6.17

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The ultimate advantage of all Yoga poses is that the patient assumes control and responsibility

for her own welfare. An agitated patient who desires more self-reliance can, with a little

ingenuity, employ these postures herself in many situations. The very fact that they have this

method of self-control actually seems to decrease many patients level of agitation.

The sympathetic fight or flight reaction is well known to produce transient elevations in blood

pressure and has been amply demonstrated. With its goal of preparing an individual for

meditation and the higher aims of spiritual endeavor, which require temperamental calm and


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emotional self-mastery, it is not surprising that Yoga promotes parasympathetic activity. This

parasympathetic activity titrates the very inducements to sympathetic vasoconstrictionsuch as

pain in the legs from these forward bendsagainst conscious and autonomic factors that reduce

the adrenergic response.

Unlike competitive or high-action exercise, in which adrenin and other internal and external

stimuli work to increase heart rate and blood pressure, and unlike repetitive treadmill or step-

exercise, which is often accompanied by reading the newspaper or watching the news, Yoga

reduces stress and reduces the adrenin, thyroid, and glucagon levels associated with stress. At

the same time, it promotes focused and unhurried concentration, coordinating conscious and

nonconscious efforts toward one goal, while sympathetic and parasympathetic systems balance

to a finer measure of equilibrium.

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Blood Pressure Reduction by Yoga