What Is Blood Pressure?

1. Our Measure of Blood Pressure What Is Blood Pressure? Blood Pressure (BP) refers to the pressure that exists within the arteries as the heart pumps blood around the body. A BP reading involves two values: the higher value is known as the systolic pressure, and indicates the pressure produced by the heart when it contracts during a beat. The lower value is known as the diastolic value, and indicates the pressure produced by the heart when it relaxes between beats. BP is affected by three aspects: the strength of each heartbeat (stronger = higher pressure), the amount of blood in the circulatory system (more = higher pressure), and the diameter of the blood vessels (narrower = higher pressure). High BP is often symptomless, but can be very dangerous for one’s health. It damages the blood vessels over time, thickening their lining and blocking them with atheroma (a fatty material). Eventually, the vessels can narrow so much that blood cannot get through, leading to clots and infarction (tissue death due to lack of oxygen). In the long-term, untreated high BP can therefore lead to a host of problems, including angina, heart attack, stroke, dementia, kidney damage and eye damage. What Causes High BP? Hypertension (high BP) can have various causes. It can be genetic (inherited), and tends to be higher in men and older people. However, lifestyle factors can also play a large role. Diet is very important: salt intake increases BP, and overweight people tend to have higher BP levels than people who are of a normal weight. A potassium-rich diet appears to have positive effects on BP, as does a diet which is high in fruit and vegetables and low in animal fats. Heavy drinkers also tend to have higher BP. Stress has the potential to increase BP (particularly in the short-term), whilst regular moderate exercise has the potential to decrease it over time. This means that lifestyle changes are generally recommended for high blood pressure, although drugs are sometimes prescribed. Why Are We Measuring BP In Our Study? Because it is related to factors such as obesity, stress and alcohol consumption, BP level is an important indicator of general health. People who have healthier lifestyles (e.g., those who eat a healthy diet, exercise regularly and avoid smoking) tend to have lower BP levels. BP level can also play an important role in predicting the occurrence of various health problems, such as heart attack and stroke. We intend to investigate the effect of group identification on BP level over time, using a longitudinal study design. It should be noted that BP levels can be somewhat variable, since they are affected by factors such as illness, short-term stress/anxiety, medicines, and how the BP reading was taken. For this reason, we are measuring two other useful health indicators: Body Mass Index and cholesterol. We expect these three measures (in combination) to provide us with a good indication of our participants’ physical health. How Are We Measuring BP In Our Study? BP is usually measured with a sphygmomanometer, which involves placing a rubber cuff around the patient’s upper arm. The cuff is inflated (tightens) and deflated (loosens) so that BP can be measured. BP is one of the measures we are obtaining through the health data stored by each participant’s GP. We will obtain each participant’s most recent measure of BP from their medical file, and use these in our study. For More Information: Email Prof. Fabio Sani: f.sani@dundee.ac.uk