Often referred to as'The Silent Killer', owing to the fact that we can suffer without being aware, high blood pressure or hypertension as it's also known, is an underlying problem often only diagnosed once a serious event such as a heart attack or stroke has occurred. It's quoted as being the second biggest global risk factor for disease (1), associated with an increased risk for heart failure, coronary artery disease and vascular dementia to name but a few.
The World Health Organisation (WHO) hypertension fact sheet published in May 2021, estimates that as many as 1.3 billion people globally have hypertension (2). The UK government report that approximately 1 in 4 adults in England are affected, and this is projected to rise to 1.5 billion by 2025 (3). Due to the correlation high blood pressure has with other potentially life-threatening conditions, we could surmise that a high percentage are living at significant risk.
In England hypertension was responsible for an estimated 75,000 deaths in 2015 and is estimated to cost the NHS roughly £2.1 billion per year. In America, the death rate relating to high blood pressure was recorded as approximately 82,735 in 2016 with an estimated direct cost of $55.9billion (4). Globally, hypertension is deemed responsible for approximately 7.6 million deaths per year. This is more than any other risk factor.
The recent Covid-19 pandemic has sent a shockwave round the world with infection rates and death rates being broadcast daily across media platforms. The resulting anxiety regarding our own personal safety and the welfare of our family and friends was pushed to the forefront, re-defining our priorities, changing our daily routines, and adapting our work and social habits. Seeing this play out, it's hard not to draw parallels and consider just how the global population would react if we had daily updates on the number of confirmed hypertension cases and a running tally on the death rates which could be attributed to high blood pressure?
What is Blood Pressure?
The body’s circulatory system is responsible for transporting blood, saturated with oxygen, from the lungs and heart out to the body via our arteries. Once this oxygen has been used by our cells, the now de-oxygenated blood travels back though our veins, to the lungs and heart ready for the process to start over again. It is a constant cycle powered by our heart, arteries out, veins back in, over and over again many, many times per day and throughout our lives.
When we get a blood pressure reading, either by our GP or on an at home device, we are familiar with the two number format, '123 over 81 or 123/81' as an example, but what does this mean? Quite simply, the pressure of our blood measured in millimetres of mercury mmHg, is recorded in two distinct phases of the circulatory cycle:
The systolic measurement (number on top or 123 in our example above), occurs when the heart contracts, pushing blood into arteries. This is measuring the force at which the heart pumps blood around the body.
The diastolic measurement is (number on the bottom or 81 in our example), is taken within the relaxation stage of the heart, as it re-fills with blood and prepares to contract again.
Variations
Blood pressure may vary for a multitude of reasons such as time of day or temperature etc. There will also be variations between children and adults as well as different age groups. The normal range for blood pressure is between 90/60mmHg and 120/80mmHg. High blood pressure or hypertension for most adults, is classified as when systolic pressure is 140 or above and the diastolic pressure is 90 or over (140/90mmHg). For those aged 80+ the high classification goes up to 150/90mmHg (5).
There are many factors which can contribute to high blood pressure, some are modifiable meaning we have the power to act to make a difference, such as changing our diet or taking exercise. Others are non-modifiable, these include things such as genetics and age.
Age (non-modifiable)
Blood pressure tends to rise with age. This is partly due to blood vessels losing some of their elasticity, becoming stiffer. Therefore, making it harder for the heart to pump blood into vessel and around the body.
Heredity (non-modifiable)
There are genetic links to many conditions, including high blood pressure. It should also be considered however that families often share lifestyle and behavioural similarities, which may influence not just blood pressure but overall health, potentially exacerbating non-modifiable factors.
Excess weight or obesity
In the UK it is estimated that 1 in 4 adults is overweight or obese (6), in the USA 36.5% of adults are considered obese and an additional 32.6% overweight (7). Globally, an estimated 2 billion people are overweight or obese (8). Although the direct processes by which the carrying of excess weight leads to hypertension is not yet fully understood, there is research which suggests hormonal and metabolic imbalances may play a role (9). With obesity consistently linked with hypertension and other potentially life-threatening conditions we need to consider if there are sensible steps we can take to help control our weight.
High Salt Diet
Salt or sodium chloride (NaCI) is an essential nutrient which our bodies require in only a small amount, to assist with bodily functions such as the conduction of nerve impulses in the contraction and relaxation of muscles, and in the maintenance of water and mineral balances in the body. Salt is generally used by most to flavour foods but it can also act as a preservative. When we consume too much salt this can lead to a retention of excess water and this in turn can cause our blood pressure to rise. A diet high in salt can over time lead blood vessels to become narrower and stiffer, meaning the heart must work harder to pump blood around the body (10).
It is estimated that our bodies require approximately 200 to 500 mg per day for optimum health (11). The UK government suggest that anyone over the age of 11 should consume no more than 6g per day (12), while the WHO define excess consumption as anything above 5g per day (13).
Excess Alcohol
Research has shown that heavy drinking can led to an increased risk of hypertension in both men and women (14). Drinking too much over a long period of time, or alternately drinking excessively on a single occasion can damage the heart or interfere with the way it works, narrowing the blood vessels and making it harder for blood to be circulated (15). Of course alcohol is also high in calories, meaning that excessive consumption can also contribute to weight gain, further exacerbating the risk. The recommendation in the UK is that we limit our alcohol intake to 14 units over three or more days. This equates to approximately 6 medium (175ml) glasses of wine or 6 pints of 4% beer (16).
Poor Diet
This could be considered a fairly vague term so for clarity we are referring to a diet high in processed foods and lacking in fresh vegetables, fruits, and proteins. Highly processed diets are often linked to weight gain, diabetes, and high cholesterol, which can potentially contribute to an increase in blood pressure. It seems straightforward therefore that having access to more varied food choices has been shown to have a very positive effect on lowering blood pressure for many. It should be noted though, that this works best when activity or exercise is also undertaken (17).
Many foods are suggested when looking to reduce blood pressure levels and promote good health. These include, but not limited to strawberries, blueberries, kiwis, watermelon, green vegetables such as lettuce, spinach, and cabbage, lentils, natural yogurts, nuts including pistachios, almonds as well as some herbs and spices such as garlic and cinnamon. Oily fish are a good source of omega-3 fatty acids which have overall health benefits, but are thought to also reduce blood pressure.
Lack of Activity/Exercise
The link between a lack of activity and exercise and hypertension is not debatable. It has been shown repeatedly that increasing activity and exercise has a positive effect in reducing high blood pressure.
Exercise strengthens the heart and maintains the health of blood vessels, which in turn benefit the efficiency of the circulatory system. Aerobic exercises are often recommended to assist in lowering blood pressure and these can including cycling, walking, jogging, swimming etc. It is advised however, to seek advice from a GP or health professional when embarking on an exercise program if hypertension has been diagnosed.
Smoking
The negative impact smoking has on our health is well documented. The fact that it can contribute to high blood pressure is only one amongst a multitude of reasons to not indulge in the practice. Nicotine raises blood pressure as well as our heart rate. It contributes to narrowing arteries and hardens their elasticated walls, which in turn makes it harder for the heart to pump blood through the body (18).
Anxiety and Stress
Anxiety doesn’t directly cause hypertension long-term, but it has been shown to increase blood pressure over a short period. If anxiety does persist, over time the accumulation can contribute to damage to the blood vessels as well as the heart and kidneys. There is also the suggestion that many sufferers are more likely to smoke, drink alcohol or eat more as result of their anxiety.
As with anxiety, there is no evidence linking stress to chronic hypertension, but there is a link between the hormones released when an individual is stressed and temporary elevations of blood pressure. The hormones produced when we face stressful situations do many things including increasing our heart rate, and constricting our blood vessels. This is part of our flight-or-fight response which is a natural and often life-saving mechanism. Occasional episodes of stress are unlikely to have a long-term effect, as once the stress is reduced, blood pressure returns to normal. However continued exposure to stressful situations may again lead to the damage of blood vessels, heart, and kidneys.
Other Factors
High blood pressure can be caused by several other factors; underlying health conditions such as kidney disease, some hormonal disorders and even pregnancy. There are also many types of medication which may have the side effect of raising blood pressure such as decongestants, cough and cold remedies, anti- inflammatories, steroids, and oral contraceptives. To add to the list even some herbal supplements can also elevate blood pressure, substances containing liquorice, arnica, and ginseng as an example, so the side affects of any such medications and any herbal supplementations should always be considered prior to taking. If in doubt, a GP or Pharmacist should always be consulted.
Reducing High Blood Pressure
We can’t stop ourselves from getting older, and we can't change our genetic pre-dispositions, but hopefully we have shown that there are some modifiable factors we can consider; namely food, exercise, smoking, and alcohol. We need to moderate as much as possible to ensure we are not contributing to, and exacerbating a potentially life-threatening condition. Of course contact with a GP or medical professional is essential whenever high blood pressure is suspected or diagnosed. There are medical interventions and medications which can assist in lowering blood pressure but these should only be used under the guidance of an expert.