Effect of Bhramari Pranayama on Heart Rate Variability (HRV) in Hypertension - A Randomized controlled trial

Hypertension is defined as the increase in blood pressure above the normal level with a systolic and diastolic more than 140/90 mmHg. It is a psychosomatic condition that affects practically everyone, regardless of race or age. Blood arteries in organs including the kidneys, heart, brain, and eyes can become damaged by increased and persistent high blood pressure, which can lead to consequences like stroke, coronary heart disease, renal failure, and blindness. Depending on the causes, hypertension is split into two categories: primary hypertension, which accounts for about 90% of all instances, and secondary hypertension, which accounts for about 10% of all cases. A kind of hypertension called as primary hypertension has an idiopathic or unexplained origin. Non Communicable Diseases (NCDs) are on a rise globally and in India. It is estimated to have caused 9.4 million deaths and 7% of disease burden as measured in disability-adjusted life years in 2010. HTN is the important non communicable disease risk factor in India with an estimated burden of two hundred million persons. Extrapolations suggest that, using current definitions, there are more than 200 million patients with hypertension in the country. Hypertension is labeled as a lifestyle disorder because of the contribution of modifiable risk factors in its development, that is, obesity, unhealthy diet (high intake of saturated fatty acid and salt, low intake of fruits, vegetables, dairy products), physical inactivity, stress, armful use of alcohol, and smoking. Hypertension is prevalent in approximately 25- 26% of world’s population. The World Health Organization (WHO) has identified high blood pressure as one of the most important causes of premature morbidity and mortality in both developed and developing countries. Globally, approximately, 7.6 million deaths occurred per year due to hypertension. According to the World Health Organization (WHO) 2008 estimates, the prevalence of raised Blood Pressure in Indians was 32.5% (33.2% in men and 31.7% in women). Physical inactivity due to usage of electronic gadgets might play a key role in development hypertension. Obesity, hypertension and diabetes mellitus are commonly seen in persons with physical inactivity. Lack of physical activity account for poor control of hypertension and increased risk of cerebrovascular disease and ischemic heart disease in patients with uncontrolled hypertension.

Yoga is an alternative therapy for stress management and to reduce blood pressure. Yoga is ancient traditional methods practiced in India for good health and prevention of diseases since last 5000- 8000 years. Yoga consists of various posture (asana), breathing practices and meditation techniques (Pranayama’s) and the most important is yogic behavior. Regular breathing practice reduces sympathetic activity, increases parasympathetic control along with improvement function of respiratory system, cardiovascular system, and neuro-endocrine system. Yogic practices are helpful in autonomic control over visceral functions. Enhanced parasympathetic control and reduced sympathetic activity is seen yogic persons and which ultimately leads to good cardiovascular health. Approximately 4-6 mmHg reduction in systolic blood pressure (SBP) and diastolic blood pressure (DBP) after yoga practices was documented in few studies. Even small reduction in blood pressure after shorter duration of intervention play key role clinically. The reduction in blood pressure which could be the effect of yoga may be useful as an additional therapy in addition to medical treatment of hypertension. Pranayama is a part of yoga, which improves pulmonary function in combination of many pranayama, but the aim of our study is to evaluate the effect of only Bhramari pranayama on heart rate variability in primary hypertension. Yoga is one such tool that can be used in the management of hypertension Pranayama ’is a Sanskrit word that literally means control of vital force (‘Prana’=vital force; ‘Yama’=control). Basically, it consists of three steps: inhalation (purak), retention (kumbhak), and exhalation (rechak).The steps of pranayama can be modified to perform different varieties of slow breathing exercises to improve its effectiveness. Bee-Humming Breathing Exercise (BHB) or ‘Bhramari pranayama’ is one such modification which involves inhalation through both nostrils and while exhalation producing the sound of humming bee as long as possible. Bee-Humming Breathing (BHB) exercise is a simple yogic practice recommended for its favorable effect on cardiac physiology, including blood pressure (BP) and autonomic nervous system. Heart rate variability (HRV) is a commonly used tool to assess the limbs of autonomic nervous system. Heart rate variability is an index of beat-to-beat changes in the heart rate and is a non-invasive assessment of autonomic control of cardiac functions. The series of time intervals between heartbeats, referred to as R-R intervals, are measured over a period of anywhere from 10 min to 24 h. Reduced heart rate variability has been associated with negative consequences to health, particularly related to negative emotions and mental stress. Voluntarily regulated breathing techniques (pranayamas) have been used either alone or in combination with other interventions to reduce stress-related disorders and conditions such as hypertension. These breathing techniques have been practiced most often with the aim of decreasing arousal by correcting the sympatho-vagal imbalance, ie, reducing the sympathetic activity and stimulating vagal efferent activity.