A heart attack is a serious medical emergency whereby the supply of blood to the heart is suddenly blocked, usually by fatty substances in the coronary arteries. Coronary heart disease is the term that describes this destructive process. There are many mechanisms that cause the supply of blood to the heart to be blocked.
One of the most common catalysts is high blood pressure, a process whereby your blood pressure constantly remains above the recommended levels.
As the American Heart Association explains, the force and friction of high blood pressure can damage the delicate tissues inside the arteries.
In turn, LDL (bad) cholesterol - a harmful fatty substance - forms plaque along tiny tears in the artery walls, signifying the start of atherosclerosis (the technical term for clogging up your arteries.
The obvious perils of high blood pressure are usually overlooked in younger age but a new study emphasises the importance of controlling your blood pressure regardless of your age.
Research led by Dr Dipender Gill from Imperial College London shows that blood pressure must be controlled by middle age, otherwise it can lead to irreversible damage.
Dr Gill's research has shown that high blood pressure at age 55 and younger increases your risk of coronary heart disease independent of high blood pressure after 55 years of age.
To put it more starkly, if you have had high blood pressure in your 40s, but controlled it in your 60s, then the damage is already done.
The research is a wake up call for people who assume it is something to worry about in their 60s or 70s.
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The scientists analysed the genes of more than 400,000 British people and calculated that every ten-unit increase in blood pressure levels before the age of 55 raised the risk of a heart attack in later life by 43 percent.
The damage, they found, was permanent. For example, if somebody had the issue in their 40s, but it was controlled in their 60s, the harm would already be done.
Study leader Dr Dipender Gill, from Imperial College London, said: "Everybody knows that high blood pressure is bad for your heart. But nobody worries about it when they are young.
"They think, "I will think about this when I'm 60, when I'm 70". But this evidence shows that the damage is cumulative, it is lifelong. So it is something that we should be thinking about when we are in our 30s, 40s and 50s – not putting off."
Dr Gill added: "We found even a small change in blood pressure has a cumulative effect on heart disease risk."
Maureen Talbot, head of clinical support at the British Heart Foundation, which funded the research, said: "Controlling blood pressure is extremely important, as it will lower your risk of serious illnesses such as coronary heart disease, heart attack and stroke.
"If you have high blood pressure when you're middle-aged, taking proactive steps to reduce it could save your life."How to lower your blood pressure
One immediate step you can take is to reduce your salt intake because salt raises your blood pressure.
The NHS says to eat less than six grams (0.2oz) of salt a day, which is about a teaspoonful.
"Eating a low-fat diet that includes lots of fibre, such as wholegrain rice, bread and pasta, and plenty of fruit and vegetables also helps lower blood pressure," adds the health body.Heart attack symptoms - what to look for
Symptoms of a heart attack can include:Chest pain – a sensation of pressure, tightness or squeezing in the centre of your chestPain in other parts of the body – it can feel as if the pain is travelling from your chest to your arms (usually the left arm is affected, but it can affect both arms), jaw, neck, back and tummy (abdomen)Feeling lightheaded or dizzySweatingShortness of breathFeeling sick (nausea) or being sick (vomiting)An overwhelming sense of anxiety (similar to having a panic attack)coughing or wheezing.
"Although the chest pain is often severe, some people may only experience minor pain, similar to indigestion," adds the NHS.