18 Oct Understanding Blood Pressure

What do the numbers mean?

When you have your blood pressure measured, it is written down as two numbers, one over the other like a fraction.

For example: 140 / 90 mmHg

It is said as ‘140 over 90’, for example. The top number, which is called the systolic pressure, shows the pressure in your arteries when your heart is forcing blood through them. The bottom number, called the diastolic pressure, shows the pressure in your arteries when your heart relaxes. The top number can be anywhere from 90 to 240 and the bottom number can be anywhere from 60 to 140. It is measured in millimetres of mercury, which is written down as: mmHg.

Everyone has a different blood pressure and it can change in the same person during the day and night. Your blood pressure varies by large amounts, depending on what you are doing. The lowest blood pressures occur when you are asleep or if you relax all your muscles. Standing up, exercising or anxiety all cause an increase in blood pressure. In a single day your blood pressure may vary by 30 to 40 mmHg systolic with similar proportionate changes in diastolic pressure. This is why when you have your blood pressure level assessed it is so important to have it measured under the same conditions every time.

What should my blood pressure be ?

140/90mmHg is the level of blood pressure used to diagnose high blood pressure. If your blood pressure is consistently raised at these levels and above, it will need to be treated. Treatment may involve making changes to your lifestyle and/or taking medication. This level of 140/90 mmHg is the level for high blood pressure for everyone, whether you are male or female, young or old.

It can be high if you have a systolic reading of 140 or above, a diastolic reading of 90 or above, or both. For example, a reading of 150/85 mmHg is high because the systolic is above 140; a reading of 139/95 mmHg is high because the diastolic is above 90. A reading of 150/95 mmHg is also high as both the systolic and the diastolic number are raised. As you get older you may find that your diastolic level is normal but your systolic level starts to rise and this is called isolated systolic hypertension. This is common among older people, and still needs to be treated.

140/85 mmHg is the optimum target blood pressure for people who are receiving treatment for their high blood pressure. The only exception to this target level is if you have diabetes, kidney disease or have already suffered a stroke or heart attack. Then it is worthwhile lowering it even further and your doctor may ask you to lower your blood pressure to an optimum of 130/80 mmHg.

When you have your blood pressure measured, always ask what it is and keep a record if you can. By doing this you can see whether your blood pressure is stable or is increasing.

I have had a high reading. What happens now?

Unless your it is very high, in order to be sure that you have high blood pressure you will be asked to have readings taken several times. This is to make sure that you have consistently high blood pressure, rather than high blood pressure because you are nervous at the doctors or have rushed to get to your appointment.

Changing Your Lifestyle

Everyone who has high blood pressure should lead a healthy lifestyle and make changes if they need to. In a few people these changes can be enough to lower blood pressure to a level where you may not need to take tablets. If tablets are necessary, a healthy lifestyle can help to make them more effective.

Lifestyle changes should be adopted by the whole family, as this may lower blood pressure and prevent high blood pressure from occurring later in life. A healthy lifestyle will also make you feel better generally. Cut down on your salt intake, eat more fruit and vegetables, be more active, find and reach your ideal weight, drink alcohol only in moderation.

As well as the five factors set out above there are two other key risk factors for stroke and heart disease, smoking and eating too much. However, these don’t in themselves cause high blood pressure. However, if you stop smoking and cut down the amount of saturated fat you eat, this will combine with lowering your blood pressure to cause a very large reduction in your risk of having a stroke or having a heart attack.

What does physical activity do to my blood pressure?

If you are regularly active and you maintain that activity in the long-term it can help you to lower your blood pressure. Most people will notice a reduction in their blood pressure within the first ten weeks after increasing the amount of activity they do. As long as you keep active your blood pressure should stay at this lower level. Physical activity can lower systolic blood pressure by an average of 4 – 9mmHg.

Is it safe to be more active if I already have high blood pressure?

Almost everyone will be able to become more active. However, make sure you check the following before you start:

Have it measured and checked with your doctor or nurse that it is safe for you to start becoming more active. If it is consistently above 180 systolic and/or 110 diastolic (180/110 mmHg), you should not be doing intensive activity until your blood pressure has been treated and lowered. If you also have other medical conditions like diabetes, heart disease (such as a previous heart attack) or breathing problems you may need different advice. Check with your doctor.

How much physical activity do I need to do?

You are aiming to do at least 30 minutes of moderate physical activity at least five days a week. You should be a little out of breath but still able to talk, warm and slightly sweaty. This much activity will burn off 150 – 180 calories a day, which could add up to a weight loss of 6-12kgs (13- 26lbs) every year. A little bit of activity regularly can make a real difference.

If you have not been active for a while then gradually build up the amount of time spent on activity, adding a few minutes each week. You can get as much benefit if you decide to do smaller amounts during the day to make up 30 minutes. For example, you could start with three ten-minute walks each day, increase to two fifteen-minute walks and then finally achieve a full 30 minutes in one go. Set yourself a series of goals to help you towards your final target.

If you are trying to lose weight, or have lost weight and are trying to maintain that weight loss, you may need to do 45-60 minutes of activity every day.

What kind of physical activity should I be doing?

Brisk walking, swimming, cycling, jogging, playing a team sport such as football or hockey, dancing and tennis are all activities that will help you to strengthen you heart and lungs (cardiovascular system). It is this kind of actively that can help you to lower your blood pressure.

As well as these kinds of activities you should also include activity that strengthens your muscles and helps you to stay supple and flexible. These kinds of activities might include climbing stairs, walking uphill, yoga, Pilates, and gardening. Doing a range of activities will stop you from getting bored and help to keep you motivated.

Some people use a pedometer, or step counter, and aim to do 10,000 steps every day. This can be a good way to set yourself goals and targets and helps you to become aware of how much (or how little) you are doing every day.

Is there any activity I should not do if I have high blood pressure?

Avoid lifting weights and very vigorous sports such as squash. If you are very overweight, have a heart or breathing condition or have not been active for a long time, check with your doctor before starting a new exercise routine.