What is blood pressure?
When a doctor/nurse/health care assistant/machine checks your blood pressure with a cuff around your arm, they are checking the pressure at which the blood is pumped by your heart. When the pressure in the cuff is raised above the pressure in the blood vessel (artery) the pulse at wrist disappears. As the pressure in the cuff surrounding your arm is gradually released, when the pressure is equal or slightly lower than the pressure in the artery, the blood starts flowing and the pulse can be felt.
This is called the systolic (the top number) blood pressure. One can also hear the noise with the stethoscope as the blood starts flowing.
As the pressure is gradually lowered the noise disappears when there is no compression of the artery. The pressure at which the noise completely disappears is called the diastolic pressure. (Lower number in the blood pressure).
Why lowering high blood pressure is important.
High blood pressure puts stress on the heart and blood vessels. This increases the risk of heart attack, and heart failure. High blood pressure also increases the risk of stroke, kidney damage and damage to circulation to the legs.
There is good evidence that lowering high blood pressure with medications lowers the risk of stroke by 35 to 40% and lowers the risk of heart attack by 20 to 25 %.
Activities to assist lowering blood pressure
Regular exercise like walking briskly for 30 minutes or more on most days of the week.
Maintain weight in the normal range. (BMI 20-25). You can check your BMI here.
Alcohol in moderation. Excess alcohol increases the blood pressure.
Drink no more than 2 pints (for men) or 1 pint (for women) at a time.
Avoid salty food and stop sprinkling salt on food.
Consume at least five portions/day of fresh fruit and vegetables a day.
Do not smoke
Do not drink more than 5 cups of coffee or tea in a day. Avoid energy and cola drinks. Energy drinks have high content fo caffeine.
Blood Pressure Readings
How to check blood pressure at home
- Sit quietly for five minutes, with your feet on the floor and your back well supported.
- Your arm should be resting on a flat surface, with the upper arm at the level of the heart.
- Position the cuff so that its midportion lies over the brachial artery. (Cuffs have marks to help with positioning.)
- Avoid caffeine (coffee, tea, cola and energy drinks), alcohol, smoking, and exercise for at least 30 minutes before taking your blood pressure.
- Each time take two blood pressure readings at least one minute apart. Record both BP recordings below.
- Check blood pressure twice a day preferably morning and evening. Check for 7 days.
The effects of raised blood pressure
A raised blood pressure increases the damage to the walls of the blood vessels in conjunction with age, smoking, diabetes and cholesterol to increase the chances of a heart attack or stroke. The exact targets vary if you have existing damage to the blood vessels indicated by having TIAs, strokes, heart attacks or diabetes.
For validated home BP machines to buy for home monitoring
see British Hypertension Society website.
We recommend you buy automatic machines with cuff going round the arm. Do not buy machines that measure BP from wrist as they can be inaccurate.
The cuff going round the arm should be appropriate to the size of the arm. If cuff is too small blood pressure readings may be inappropriately high. If the cuff is too big for the arm BP can be inappropriately low. Automatic machines may be inaccurate if you have irregular pulse like atrial fibrillation