million new cases being diagnosed each year, hypertension is a challenge
to the medical profession and a common problem facing many Americans
today. Current conventional treatments for treating hypertension decrease
peripheral resistance, blood volume, or the strength and rate of myocardial
contraction. Some patients are resorting to alternative medicine either
as a supplement or substitute. Prior research has found a variety of
alternative therapies to be successful in reducing high blood pressure,
including diet, exercise, stress management, supplements, and herbs.
Stress is one of the factors that cause secondary hypertension. In this
research study, yoga is explored as a stress reducing activity, thus
moderating the effects of stress on hypertension.
pressure affects twenty five percent of American adults1. There has
recently been an increasing awareness of the effectiveness of alternative
medicine, which explores the extent of the connection between the mind
and body, part of which is a result of influences from Asia where practices
of acupuncture and natural healing are preferred to medications. Yoga
has grown quickly in popularity in the United States as well as in many
other Western nations. High blood pressure is a condition that has an
incredibly high mortality rate in this country. 31.6 percent of Americans
with hypertension do not know that they have it2.
pressure describes the high force of blood against artery walls. It
means that the heart is working much harder than the heart of a normal
healthy human. Hypertension is a dangerous condition that does not have
a cure, but it can be kept in check by taking medications regularly
and by eating healthy meals
practice of controlling the mind and body, is an ancient art that began
in India over thousands of years ago. Because it involves breath control,
meditation, and physical postures, it is supposed to increase the vitality
of the human body, help with concentration, calm the mind, and improve
common physical ailments (Lamb, 2004).
is relatively little information that directly links yoga with high
blood pressure, there is a common factor that the two subjects share-
stress. Numerous references and sources discuss a relationship between
hypertension and stress as well as a relationship between relaxation
techniques and stress. In the next sections, this paper will explore
the question of whether there is a definite correlation between yoga
and hypertension, and, if so, whether there is a causal relationship
present, where a regular practice of yoga would have a positive effect
on lowering high blood pressure.
is experienced when "emotional, physical, or environmental demands
challenge or exceed a person's personal resources and ability to cope
effectively" (Sheps, 2002). There are two types of stress, namely
acute stress and chronic stress. Acute stress is transitory, while chronic
stress occurs for a prolonged period of time (Hendrickson, 2004).
response, also called the general adaptation syndrome (or the "fight-or-flight"
response), relates to acute stress and is a "physiological reaction
that rallies you to action when you encounter a perceived threat"
(Sheps, 2002). There are three stages of the stress response. First,
there is the alarm reaction, which occurs when you are alert and on
your guard and when your arteries constrict and heart rate speeds up.
During this stage, you feel threatened by someone or something, and
the muscles tense and respiration increases. When you are ready to fight
the challenge, the resistance reaction kicks in, and during this stage
the respiration rate, blood pressure rate, and temperature remain high.
Once the threat is past, the rush of stress hormones subsides, and blood
pressure, pulse, and respiration rates all return to their normal levels
in chronic stress, where stress is continuous, hormone levels remain
elevated, and the body permanently keeps the ready state (Whitaker,
2000); during chronic stress, the body is constantly feeling stressed
or threatened, and so the resistance state remains. The muscles remain
tense, the pulse rate remains high, and the blood pressure increases.
The last stage, known as the exhaustion stage, occurs when the adrenal
hormone stores are depleted and organ systems begin to fail (Sheps,
2002). The accumulation of stress contributes to the onset of many diseases
and conditions. One of those conditions is high blood pressure or hypertension.
pressure is the most common chronic illness in the United States (Sheps,
2002). It is a condition that is common among people over the age of
35. According to Dr. Suresh Ramasubban, a pulmonary physician at Rush
Hospital in Chicago, blood pressure is largely the result of two main
forces. The first force, called the stroke volume, is the force created
as the blood is pumped into the arteries. The second force is created
as the arteries resist the blood flow. Hypertension is a type of cardiovascular
disease characterized by elevation of blood pressure above the level
considered normal for people of similar racial and environmental backgrounds.
Because it affects the entire circulatory system, hypertension can be
detrimental to all the major organs, including the heart, brain, and
kidneys. It may contribute to death from heart failure, heart attacks,
stroke, and even kidney failure.
Hypertension is defined as "an abnormal condition in which the
blood pressure exceeds the accepted normal reading of 140/90" (Fortmann
& Breitrose, 1996). The first number refers to the systolic pressure,
which occurs when the blood pressure is at its highest when the left
ventricle of the heart contracts. The second number, the diastolic pressure,
is the lowest blood pressure when the heart is at rest (Rowan, 1986).
two types of high blood pressure: essential and secondary. Essential
high blood pressure is the more common, affecting over ninety percent
of high blood pressure patients. However, it is different from secondary
hypertension because it does not have an obvious cause (Sheps, 2002),
making it more difficult to diagnose hypertension, since high blood
pressure is usually symptom-free (Fortmann & Breitrose, 1996).
Stress and Hypertension
and studies point to a direct relationship between stress and high blood
pressure. Chronic stress increases blood pressure (Whitaker, 2000).
This is demonstrated by the fact that during a period of stress, the
body releases the hormones epinephrine (adrenaline) and cortisol, which
increase high blood pressure by narrowing the blood vessels and increasing
the heart rate (Sheps, 2002). Also, prolonged stress causes resistance
and exhaustion (Whitaker, 2000). In a recent study, 200 men who had
worked at stressful jobs for at least 25 years were interviewed. The
study showed that there was a 4.8-point rise in systolic blood pressure
when the men were at work and a 7.9-point rise when the men were at
home (Landsbergis, Pickering, Warren, & Schwartz, 2003).
controllers tend to develop high blood pressure at almost six times
the rate of people in lower stress jobs (McGowan & McGowan-Chopra,
2001). Cloistered nuns were much less likely to develop high blood pressure
than were women of their same age living in the same geographical area
but exposed to the stresses of everyday life (McGowan & McGowan-Chopra,
2001). Police officers of the Buffalo police force as a group have higher-than-average
pulse rates and higher diastolic blood pressures (Baker, 2004). The
research conducted so far on the effects of stress reduction seems to
have a positive association with hypertension (Whitaker, 2000; Sheps,
2002; McGowan & McGowan-Chopra, 2001; Baker, 2004).
medicine may be the common cure to almost all ailments, there are claims
of alternate therapies that control high blood pressure. One such claim
is yoga and this therapy has been recently introduced to the Western
an ancient art that is defined as the union of the soul with God (Anand,
2000). It is "a path of personal spiritual development that utilizes
meditation to bring enlightenment, self-realization, and, ultimately,
the attainment of God and bliss" (p. 109). Originally, the ultimate
goal of yoga was called samadhi, or self-realization (Iyengar,
four types of yoga: Raj yoga, Karma yoga, Jnana yoga, and Bhakti yoga
(Anand, 2000). Raj yoga, which is the yoga of meditation or concentration,
is the type that is most commonly used in the West today. The Raj yoga
consists of eight steps, and each step involves self-control, muscle-relaxation
postures, breath control, concentration, and deep meditation. Three
out of the eight steps are most common in the Western world: Pranayama,
Asana, and Dhayana (Mishra, 1987). Pranayama utilizes breath control,
where the breath is harnessed during inhalation and exhalation. The
asanas are the different postures that help to tone the body. Dhayana
consists of meditation and concentration.
meditate comes from the Latin word meditari, which means, "to
think or reflect upon" (Bonadonna, 2003). The most popular form
of meditation is called Transcendental meditation (Sorgen, 2002). It
is defined as a simple mind-body technique that allows you to gain a
unique state of restful awareness or alertness. Mindfulness meditation
is the more difficult of the two (Bonadonna, 2003). It is defined as
attempting awareness of the whole perceptual field. More than 2 million
Americans have learned meditation over the past years (Bonadonna, 2003).
Recent studies and evidence have demonstrated that such yoga practices
are effective in reducing stress.
substantial evidence that yoga and stress are directly linked. According
to yoga, stress is an imbalance at the mental, physical, or emotional
level. Yoga is directed at improving our ability to cope with stressors.
The tension associated with stress is stored mainly in the muscles,
the diaphragm, and the nervous system. If these areas are relaxed stress
is reduced, minimizing the impact of stress on the individual (Iyengar,
2001). In a study involving 73 elderly men and women, some of them were
asked to meditate daily (Myers, 2001). After three years, one-fourth
of the nonmeditators had died, while all of the meditators were still
alive (Myers, 2001). An 8-week study was conducted on medical and premedical
students to see if regular meditation for the 8-week period would make
the students less anxious and stressed during an examination period
(Bonadonna, 2003). The results were positive, the meditation did lower
the stress and anxiety level of the students (Bonadonna, 2003).
study led by Dr. Schneider, Dean of the College of Maharashi Vedic Medicine
at the Maharashi University of Management in Iowa, transcendental meditation
(TM) was compared to muscle relaxation in its effectiveness in controlling
stress (Sorgen, 2002). Out
of the 197 participants, the TM group had a significant reduction in
blood pressure in comparison to the progressive muscle relaxation group.
Another study took place at the University of Wisconsin at Madison,
where brain imaging was used to show that meditation shifts the brain
activity in the prefrontal cortex (which is the area of the brain directly
behind the forehead) from the right hemisphere to the left (Stein, 2003).
By meditating regularly, the brain is reoriented from a stressful fight-or-flight
mode to one of acceptance, a shift that increases contentment (Stein,
conducted by the TM program measured the amount of cortisol in the body
as participants of the study relaxed. The experimental group, where
the participants meditated, had a significant drop in the level of cortisol
during the meditation, and the cortisol level only rose slightly after
the meditation was completed (Stein, 2003). On the contrary, the control
group, where participants simply relaxed with their eyes closed, had
only a small change in the level of cortisol both during and after the
relaxation (Stein, 2003). The research conducted thus far on the effects
of yoga, i.e., relaxation of muscles and mind on stress prove that yoga
reduces stress (Iyengar, 2001; Myers, 2001; Bonadonna, 2003; Stein,
treatments have been researched extensively in recent years. Lifestyle
modifications, also termed as non-pharmacologic therapy, have an important
and expanding role that complements drug therapy (Appel, 1999). Also,
non-pharmacologic therapies can serve as initial therapy in Stage 1
hypertensive patients, facilitate medication step down or withdrawal
in patients with well-controlled hypertension, and prevent hypertension
in high-risk populations (Appel, 1999). Current research illustrates
that yoga reduces stress (Stein, 2003; Iyengar, 20001; Bonnadona, 2003)
and that by reducing stress, hypertension can be reduced (Whitaker,
2000, Landsbergis, et al., 2003; Sheps, 2002; McGowan & McGowan-Chopra,
2001). This paper proposes that yoga has a moderating effect on hypertension
on stress as illustrated in Figure 1. This moderating effect can be
used as a supplementary treatment to hypertension. Yoga practice unites
the mind and body activities and offers stress management techniques
essential in managing hypertension. However, it is impossible to conclude
that there is a causal relationship. The only way to demonstrate that
a continuous practice of yoga actually lowers hypertension would be
to conduct a controlled study that directly tests yoga and its effect
on hypertension. There is one such study being conducted at the Duke
University Medical Center3. Known as the "Calm Down" study,
it looks at whether practicing meditation and relaxation techniques
can lower hypertension by reducing the effects of stress. This study
is currently in progression and is expected to last for at least one
CDC's High Blood Pressure Fact Sheet (http://www.cdc.gov/cvh/library/fs_bloodpressure.htm)
2From AHA statistics (http://content.nhiondemand.com/dse/consumer/HC2.asp?objID=100228&cType=hc)
University Medical Center (http://www.dukehealth.org/clinicaltrials/20041109141616610)
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