High Systolic Low Diastolic Blood Pressure
Blood Pressure Measurement Units
Blood pressure is quoted in millimetres of mercury (mm Hg). There are two numbers which are normally written, for example, as 120/80 and pronounced ‘one twenty over eighty’. This is around the optimum pressure, (although 110/70 is sometimes quoted as a more preferable blood pressure), and is common for people who have normal blood pressure.
Systolic and Diastolic Blood Pressure
The first reading is known as the Systolic pressure, and this is defined as the pressure when the heart ‘beats’, and reflects the pressure in the aorta which is the the large artery which carries blood coming out of your heart, and aorta’s primary branches that carry blood around the body. The systolic pressure is always the largest number, and represents the highest pressure of blood during each heartbeat as blood is pumped into the arteries.
The second reading is known as the Diastolic blood pressure, (resting blood pressure) and refers to the pressure inside the aorta and it’s various branches between each heart beat. Blood that remains in the Aorta after the beat creates the pressure that forms the diastolic reading, and it exits the aorta prior to the next beat.
Blood Pulse Pressure
This term defines the difference between the two different blood pressure readings. For most people the pulse pressure should be approximately 40 mm Hg. This is the formal figure, although it can vary by a few points without being seen as unusual.
How the aging process affects blood pressure
Your blood pressure is unlikely to stay static as you progress through the various life stages from childhood, adolescence, early adulthood, and then middle and old age. Young people’s aortas are supple and and flexible so they can easily enlarge and stretch as blood enters the vessel. Because of this expansion the pressure is kept relatively low which is why most young people have healthy normal or low systolic blood pressure readings.
However, in older people the aorta begins to get more brittle, which can be aggravated by diet and other lifestyle choices. As it hardens it is able to expand less, and so it exerts greater resistance to the heart beat, and this is why the Systolic blood pressure reading tends to increase with age. The medical profession have a target of less than 140 mm Hg systolic pressure for a 50 year old person, unless suffering from kidney problems or diabetes, in which case this is reduced by 10 points.
Why do some people have much lower diastolic bp than systolic blood pressure?
As the systolic pressure rises with age due to the stiffening of the aorta, more blood is forced into surrounding blood vessels during the heart beat, and this then causes less volume of blood remaining during the resting phase to maintain the diastolic blood pressure, which is why it can become significantly lower than the rising systolic. This can develop into diastolic hypotension.
Lowering systolic pressure is the physician’s primary treatment goal
High systolic and diastolic blood pressure are both undesirable, and are responsible for an increased risk of heart attack and stroke. Because of this, doctors almost always aim to treat the high systolic pressure. However, this may sometimes result in an even larger gap between the systolic and diastolic readings.
Under 50 years of age
When people under 50 years old develop blood pressure problems it is more common to experience raised diastolic blood pressure readings – diastolic hypertension, which then stabilise or even fall.
Over 50 years of age
People aged over 50 years tend to suffer from higher systolic blood pressure – systolic hypertension, but the diastolic pressure may fall as a result as explained above. Lower diastolic pressure means that the pulse pressure also tends to get larger.