Cholesterol is a fatty substance that is present in your blood. High cholesterol, also known as hypercholesterolemia, occurs when there are raised levels in your body. Fatty substances build up in your blood mainly due to diet and lifestyle choices. Eating unhealthy fatty foods and not exercising enough puts you at risk of developing high cholesterol. If you smoke or drink alcohol or are overweight, your risk increases further. Too much cholesterol can cause a blockage in the blood vessels. There is a link between the increasing blockage of blood vessels and a higher risk of having a heart attack or a stroke. If someone in your family has high cholesterol, then you are also more likely to suffer from it. There are no symptoms of high cholesterol, the only way to confirm this is with a blood test.

A deep vein thrombosis (DVT) is a blood clot that develops in a large vein, usually in the lower leg, and requires treatment to ease symptoms and prevent clots from spreading to other areas in the body. A pulmonary embolism (PE) is the most serious complication, where part of the DVT breaks off and a clot lodges in one of the blood vessels going to the lungs, blocking the blood supply. This can cause difficulty in breathing and collapse – it's a life-threatening condition that requires immediate medical attention. It’s believed that around 900,000 people in the US have a DVT or PE every year.

A heart attack, also known as myocardial infarction or coronary thrombosis, happens when a coronary artery (a blood vessel that supplies the heart with blood) that carries oxygen-rich blood to the heart is blocked. If the blood supply is completely blocked, part of the heart muscle may be starved of oxygen, can become damaged and may die. The medical name for a heart attack is an acute myocardial infarction (MI). Although having a heart attack is very serious, the chances of survival are greatly increased if you are able to get to a hospital right away. A heart attack may also refer to a problem with the rhythm of the heart – an arrhythmia – that prevents it beating in synchrony to pump blood around the body effectively. Again, this can lead to a medical emergency. What causes an MI? Certain things can put you at higher risk of an MI. Age is the biggest factor, where our arteries become less elastic as we age, and we get build-up of plaque on the inside of the arteries (a bit like lime scale in a water pipe). Plaque causes less effective flow of blood as the tube is narrower, and a piece of plaque may break off to form a clot, causing a blockage. Other conditions can accelerate this process, including diabetes, high blood pressure, abdominal aortic aneurysm, high cholesterol, obesity, excess alcohol and smoking. Your family history or ethnicity can cause early-age plaque build-up in the arteries.

Low blood pressure (BP), or hypotension, can cause symptoms of feeling lightheaded, dizzy, feeling a bit weak, sick, disoriented, and suffering momentary blurred vision. It can cause you to faint. It may also cause no symptoms. It’s diagnosed when a BP machine gives a reading of less than 90/60 mmHg. A healthy BP should be less than 120/80 mmHg. You might have a slightly faster heart rate (the third number on the BP machine) to make up for the low BP, in order to keep blood flowing to your vital organs.

Coronary artery disease (CAD) is a form of coronary heart disease (CHD) and is where blood flow to the heart muscle is slowed down or blocked, reducing the amount of oxygen available for the heart to function normally. The typical cause of CAD happens gradually over many years, where the walls of the heart arteries slowly become ‘clogged up’ with deposits of fatty substances, called atheroma. This process is called atherosclerosis and the atheroma is often known as ‘plaques’. These plaques can build up and cause the vessels to become inflamed and damaged, causing a partial or complete blockage, and conditions like angina, heart attacks and heart failure may follow as a result. CAD develops over a lengthy period of time – usually years or decades – which can mean it takes time before symptoms develop. Some damage can be repaired with lifestyle changes and medication, surgery may be suggested in some cases, but some damage may be permanent. Many factors can cause atherosclerosis including high cholesterol levels, diabetes, obesity, high blood pressure, smoking and drinking too much alcohol.