Blood Pressure
What is (high) blood pressure?
Blood pressure (BP) is a force that moves blood through our circulatory system, delivering oxygen, nutrients, immune cells, hormones etc to all body tissues, while simultaneously collecting and removing waste products. (The lymphatic system carries extra tissue fluid and waste materials back into the blood.It handles about 20% of that work). Blood pressure must be high enough to allow for proper perfusion of body tissues and organs, but not so high as to cause injury to blood vessels.
You can quickly self-test how well you are perfusing by pressing on a small area of skin. This pressure squeezes blood out of the tiny capillaries beneath the skin’s surface, causing the skin to temporarily turn white. When you remove your finger, the capillaries should refill with blood and return to their normal color within less than 2 seconds. If the capillary refill time is noticeably prolonged, it may indicate poor peripheral perfusion or dehydration. Note, this test is more reliable in children than adults.
Arterial blood pressure directly corresponds to cardiac output (stroke volume x heart rate) & peripheral resistance.
BP is measured within large arteries. The reading consists of systolic and diastolic numbers.
Systolic - max pressure when the heart muscle contracts to send blood through the body. 90 to 120 mm/Hg is considered normal range.
Diastolic - the lowest pressure within the large arteries during heart muscle relaxation between beats. 60 to 80 mm/Hg is considered normal range
Normal BP varies from person to person depending on age and medical history. But is considered high when it consistently rises above 140/90 mm/Hg.
‘’hypertension may play a role in optimizing the blood flow and enhancing oxygen delivery. An increase in blood pressure brings about a threat of catastrophes. Therefore, hypertension might be considered as either a subsequent complication, or an inevitable adaptation.’’ https://www.ejinme.com/article/S0953-6205(08)00209-4/abstract
Why does blood pressure rise chronically, beyond the typical normal physiological fluctuations that occur throughout the day?
Stress increases sympathetic nervous system activity, which affects the heart by causing stronger, more forceful beats and influences the blood vessels by promoting constriction. When blood vessels become either thickened or excessively constricted, this leads to increased systemic vascular resistance. Additionally, a high refined salt (sodium chloride) intake makes it more difficult for the kidneys to excrete sodium efficiently. The resulting elevated sodium levels in the blood cause water retention, which increases blood volume, cardiac output, and stroke volume, thereby raising the pressure exerted against the walls of blood vessels.
Other significant risk factors include sedentary lifestyle, smoking, excess caffeine, alcohol, obesity, diabetes, chronic inflammation, oxidative stress, all of which contribute to elevated blood pressure and vascular damage over time.
Nutritional deficiencies – B, D3, Magnesium, Potassium, Calcium
High Homocysteine levels. Homocysteine is an amino acid in the blood that helps create proteins. Vitamin B12, vitamin B6 and B9 break down homocysteine to generate other chemicals in your body. High Homocysteine levels may be due B vitamin deficiency and can cause damage to the artery walls
Age related stiffening of blood vessels- elastic tissue in arterioles is replaced by inelastic fibrous tissue.
Oral contraceptives, HRT.
Substances causing sympathetic nervous system activity increase, called sympathomimetics. Can manisfest with altered mental status, diaphoresis, hypertension, tachycardia.
Some medical conditions can cause secondary hypertension, including Chronic Kidney Disease, various Endocrine disorders, certain neurological disorders, Aortic disease, and Sleep apnoea. These underlying health issues contribute to elevated blood pressure levels beyond primary hypertension causes.
How does the body regulate blood pressure?
Atrial Natriuretic Peptide (ANP)
Bodily mechanism of reducing blood pressure is Atrial Natriuretic System that works through the action of Atrial Natriuretic Peptide ANP. Atrial natriuretic peptide is released primarily in response to varying concentrations of electrolytes and water in the body and in response to stretch on the atrial wall due to increased volume . ANP lowers blood pressure, primarily by vasodilation and the inhibition of sodium reabsorption by the kidney, having a diuretic effect. This system increases sodium excretion in part through the opposition of the renin-angiotensin-aldosterone system, inhibiting renin and aldosterone release. ANP has also been shown to have inhibitory effects on vasopressin.
Renin-Angiotensin-Aldosterone System (RAAS)
RAAS works to increase blood volume and systemic vascular resistance. In response to low BP, low SNS activity and low sodum Renin is released by the kidneys → renin in the blood reacts with angiotensinogen (continuously produced by the liver) = angiotensin I → angiotensin I travels to the pulmonary vessels, where the endothelium produces the angiotensin-converting enzyme (ACE). Angiotensin I is then converted to angiotensin II by ACE. ACE, which is found primarily in the lungs, also rids the body of a vasodilator called bradykinin, causing further vasoconstriction. Angiotensin II causes vasoconstriction throughout the body. Helps maintain GFR, increases sodium reabsorption within the kidney tubules, stimulates antidiuretic hormone (ADH) and aldosterone release. Aldosterone released by the adrenal glands upregulates Na+/K+ pumps – this leads to increased reabsorption of sodium, as well as increased secretion of potassium. The increase in sodium reabsorption leads to passive reabsorption of water and an increase in blood pressure
Anti Diuretic Hormone (ADH)
ADH is made in the hypothalamus and released from the posterior pituitary in response to high plasma osmolarity, low blood volume, decreased blood pressure and Angiotensin II . ADH mainly functions to increase water reabsorption in the collecting duct of the nephrons within the kidney, causing an increase in plasma volume and arterial pressure. ADH in high concentrations has also been shown to cause moderate vasoconstriction, increasing peripheral resistance, and arterial pressure
Daily regulation of BP
Baroreceptor Reflex mechanism regulates systemic blood pressure in the short term, maintaining homeostasis through the day. Baroreceptors are located in the aortic arch and carotid sinus. They respond to changes in blood pressure by detecting the stretching of blood vessel walls when blood pressure increases or by the lack of such stimulation when blood pressure decreases. The arterial baroreceptors transmit signals to the central nervous system (CNS) through the glossopharyngeal and vagus nerves. In response, the CNS adjusts autonomic activity by decreasing sympathetic nervous system output and increasing parasympathetic activity, specifically targeting the cardiovascular system, in cases of elevated blood pressure. During low blood pressure situations, the CNS increases sympathetic activity and decreases parasympathetic influence to restore BP.
Autoregulation
The body also has a mechanism to protect organ blood vessels from natural daily BP fluctuations. It is called autoregulation – the organs are capable of adjusting their local blood flow and pressure in their local blood vessels, independent from systemic pressure. Autoregulation is impaired if there is any damage or disease processes in the local blood vessels.
How can we optimise blood pressure using herbs?
The body naturally reduces blood pressure by increasing diuresis and natriuresis, which involves the excretion of sodium and water to decrease blood volume. To support this process, we can utilize diuretic herbs in the short term to assist the body’s natural mechanisms. A classic herbal formula for this purpose is CAT, which consists of Crataegus spp. Hawthorn berries, Achillea millefolium - Yarrow herb, and Taraxacum officinale - Dandelion leaves. These herbs work synergistically to promote fluid balance and support cardiovascular health.
But the main principle of the herbal approach is to optimise blood flow throughout the body. by supporting the systems and processes involved. Herbs with circulatory stimulant, vasodilatory, anti-inflammatory, antispasmodic, antioxidant, adaptogenic, and nervine actions are utilised for promoting overall cardovascular health. These herbs work synergistically to support blood flow, reduce inflammation, relieve smooth muscle spasms, combat oxidative stress, improve resilience to stress, and support nervous system function.
Circulatory stimulants include herbs such as Cayenne pepper, Ginger, Cinnamon, Hawthorn, Ginkgo biloba, and Prickly Ash.
Herbs known as Adaptogens can be taken safely over the long term and will provide a wide range of health benefits. These natural substances help the body adapt to stress, support overall balance, and enhance resilience. Cardiovascular-specific adaptogens that are commonly used include Withania somnifera (Ashwagandha), Panax ginseng, Siberian ginseng, Reishi mushroom, Schizandra, Tulsi (Holy Basil), Astragalus membranaceus, and Jiaogulan.
To promote deep relaxation and support sleep, consider the following herbal remedies: Passiflora incarnata, commonly known as Passionflower; Scutellaria lateriflora, also called Skullcap; and Humulus lupulus, known as Hops, Valeriana officinalis. These herbs have long been valued for their anxiolytic and calming properties.