Blood pressure is the force of the blood pushing against the walls of the arteries. Each time the heart beats, it pumps blood through the arteries. Your blood pressure is at its highest when the heart beats, forcing blood into the arteries. This is called systolic pressure. When the heart is at rest, between beats, your blood pressure falls. This is the diastolic pressure.
Blood pressure is always given as two numbers, the systolic and diastolic pressures. Both are important. The systolic pressure is the first or top number, and the diastolic pressure is the second or bottom number (for example, 120/80). If your blood pressure is 120/80, you say that it is “120 over 80”.
In the early 1900s it was recognised that high blood pressure was a major cause of strokes and heart attacks.
When the level stays high, such as 140/90 or higher, you have a condition called high blood pressure or hypertension. With high blood pressure, the heart works harder to pump blood through your arteries, your arteries take a beating from having the blood forced into and through them, and your risks of a stroke, heart attack, kidney problems, and dementia are greater.
Hypertension is dangerous because it causes the heart to work harder. When the heart is forced to work hard for an extended period of time, it tends to enlarge. A slightly enlarged heart can function well, but a significantly enlarged heart cannot. High blood pressure also causes damage to the arteries, causing arterial disease.
Hypertension can be treated. Mild cases of hypertension can be treated through behavior modification like changing diet and increasing exercise. More severe cases of hypertension require medications like diuretics and beta blockers. Diuretics rid the body of excess fluids and salt. Beta blockers reduce the heart rate and the heart’s output of blood.
Low blood pressure occurs when someone has readings below 90/60 mmHg. In then early 1900s, it was believed that low blood pressure was a major cause of depression and tiredness. At this time, many people were quite wrongly treated for low blood pressure. However, there is no evidence that low blood pressure causes either of these symptoms.
The higher your blood pressure, the higher your risk of heart disease and stroke, whatever your level is. This means that someone with a blood pressure of 120/80 mmHg is at greater risk than someone with a blood pressure of 110/70 mmHg. This is why it is so important for everyone to lead a healthy lifestyle to make sure that their blood pressure is as low and as healthy as it can be.
Until recently, normal blood pressure was considered to be the average blood pressure of the population, which is approximately 125/80 mmHg. However, this is not an ideal blood pressure.
Current evidence suggests that if your blood pressure is less than 100/70 mmHg, your risk of a stroke or heart attack is very small and therefore the best blood pressure to have would be below 100/70 mmHg.
The Yamomamo Indians who live in the tropical jungle of Venezuela and still lead the same lifestyle that all humans led until about 1,000 years ago, with a diet consisting of fruit, vegetables, roots, and small amounts of meat. They have an average blood pressure of 96/62 mmHg and this does not rise as they get older. They also have average cholesterol of around 3.1 mmol/L and do not develop any disease of the arteries.
In a tiny minority of people with low blood pressure, there may be an underlying cause that requires treatment. However, most people with low blood pressure are extremely lucky because on average they are going to live longer and have better tong-term health prospects.
If you have low blood pressure and are worried that you might have one of the rare conditions which is causing it, then seek appropriate medical advice.