No pressure, but get it checked
Dr Tom Mulholland is an Emergency Department Doctor and GP with over 25 years’ experience in New Zealand. He’s currently a man on a mission, tackling health missions around the world.
What is blood pressure, why is it important and what can you do about it? Maybe we should rename it to heart pressure because when the cuff tightens around your arm it is really measuring the pressure in your heart. Blood pressure is made up of two numbers, the systolic and the diastolic pressure – fancy names that basically mean the heart’s maximum pressure and resting pressure.
When the heart contracts it sends a pressure wave through your arteries as the blood is pushed to the extremities. The blood pressure cuff is traditionally pumped up tight so it squeezes the artery closed so no blood can get into the arm. When the pressure of the heart overcomes the pressure in the cuff we record that as the systolic pressure as blood starts to flow through the compressed artery. Once the artery opens to its full diameter, the blood flow becomes laminar so it makes no noise and we record that as the diastolic or resting pressure of the heart as the chambers fill with blood. If the pressure in the heart and the arteries becomes too high or too low it can cause problems, some of them fatal. Blood vessels can burst under high pressure and depending on their location the lack of blood to whatever is downstream, such as the brain, can be problematic.
If the pressure is too low, such as under 90/60, it can cause light headedness, fainting and collapse. An ideal blood pressure is thought to be somewhere around 115/80. Elevated pressures over 140mmhg (millimetres of mercury) systolic can cause heart failure as the pump pushes against elevated pressure in the system. So, it’s important to know the pressure in your heart and the pipes, and if it’s abnormal to do something about it.
Blood pressure is essentially generated by three factors. How much fluid is in the system; the diameter of the pipes; and the rate that the heart pump contracts. Stress causes an increase in heart rate and constriction of the arteries which pushes blood pressure up. New wearable devices such as wrist bands can also measure blood pressure, making it easier to record and track it across a variety of situations.
As our blood does not like to be too salty, when we add salt to our diet, we must retain water to maintain the same concentration of salt in our blood. When we are young we can compensate for this by our blood vessels expanding, as we age the pipes harden and calcify so blood pressure goes up as frozen peripheral resistance can’t let the pressure off.
There are many other causes of elevated or low blood pressure – obesity, tumours and hormonal problems, to name a few. Abnormal blood pressure can be a warning light. So, get it measured, if it’s abnormal make the necessary lifestyle changes and, if required, take the necessary pills.
Ignoring your blood pressure can impact your wellbeing, so get on top of it before it gets on top of you.