1. The Cardiovascular System

Your heart, blood vessels and circulation

How the cardiovascular system works

The heart is a muscular pump with four chambers. The right side receives blood that has delivered its oxygen to the body and pumps it to the lungs. There, carbon dioxide is removed and oxygen is added. Oxygen-rich blood returns to the left side of the heart, which pumps it around the body through the aorta and the arterial system.

What does it do?

·  Delivers oxygen to the brain, muscles and organs

·  Transports nutrients and hormones

·  Removes carbon dioxide and metabolic waste

· Supports immune function

·  Helps regulate body temperature

·  Maintains blood pressure and tissue circulation

Common cardiovascular conditions

High blood pressure

Hypertension means blood pressure remains persistently higher than it should be. It often causes no obvious symptoms but, over time, can increase the risk of heart attack, stroke, heart failure and kidney disease.

Coronary heart disease

Atherosclerotic plaque can develop in the coronary arteries that supply the heart muscle. Reduced blood flow may cause angina, often felt as chest pressure, tightness or discomfort during exertion.

Heart attack

A heart attack occurs when blood supply to part of the heart muscle becomes severely reduced or blocked, most commonly because a clot forms in a diseased coronary artery. A suspected heart attack is an emergency.

Heart rhythm problems

An abnormal heart rhythm is called an arrhythmia. Atrial fibrillation is a common example. Arrhythmias may cause palpitations, breathlessness, dizziness, fatigue or fainting, although some cause few symptoms.

Heart failure

Heart failure does not mean the heart has stopped. It means the heart cannot pump blood as effectively as the body requires. Breathlessness, reduced exercise tolerance, fatigue and swollen ankles are common symptoms.

Heart valve disease

The heart has four valves that keep blood moving in the correct direction. A valve may become narrowed or leaky, sometimes causing breathlessness, fatigue, chest discomfort, palpitations, dizziness or fainting.

Stroke

• Most strokes are caused by disruption of blood flow to part of the brain. Think FAST: Face weakness, Arm weakness, Speech difficulty, Time to call 999.

Peripheral arterial disease

Atherosclerosis can affect arteries supplying the legs. A typical symptom is pain or cramping while walking that improves with rest.

Symptoms worth knowing

Cardiovascular problems can present in many different ways. Symptoms do not always mean heart disease, but persistent, severe or unexplained symptoms should not be ignored.

·  Chest pain or pressure

·  Unexplained breathlessness

·  Palpitations or a racing/irregular heartbeat

·  Fainting or near-fainting

·  Persistent dizziness

·  Swollen ankles or legs

·  Unusually reduced exercise tolerance

·  Leg pain or cramping during walking

What increases cardiovascular risk?

Cardiovascular disease usually develops through a combination of ageing, genetics, lifestyle and other health conditions. Many important risks can be reduced or treated.

·  Smoking

·  High blood pressure

·  Raised LDL cholesterol

·  Diabetes

·  Physical inactivity

·  Obesity and metabolic disease

·  Unhealthy dietary patterns

·  Excessive alcohol use

·  Family history of premature cardiovascular disease

·  Increasing age

Do not smoke

Smoking damages blood vessels and increases the risk of heart attack and stroke. Stopping improves cardiovascular health at any age.

Be physically active

Regular movement and exercise can improve cardiovascular fitness, blood pressure, insulin sensitivity, sleep and mood.

Know your blood pressure

High blood pressure often causes no symptoms. Periodic measurement can identify a problem before it causes damage.

Manage cholesterol and diabetes

Where treatment is indicated, controlling cholesterol, blood glucose and other metabolic risks can substantially reduce cardiovascular risk.

Eat for overall health

Healthy dietary patterns generally emphasise vegetables, fruit, whole grains, pulses, fibre, nuts, seeds, unsaturated fats and fish where appropriate, while limiting excessive salt and highly processed foods.

Sleep matters

Poor sleep and untreated sleep disorders can affect cardiovascular health. Loud snoring, witnessed pauses in breathing and severe daytime sleepiness can suggest obstructive sleep apnoea and deserve assessment.

How the cardiovascular system is investigated

Doctors choose tests according to the symptoms or condition being investigated. There is no single test that can rule out every cardiovascular problem.

Mind × Body

The cardiovascular system has strong links with mental health and neurodevelopment. Stress and anxiety can activate the sympathetic nervous system, increasing heart rate and blood pressure. Panic can cause chest tightness, palpitations, breathlessness, sweating and dizziness - symptoms that can feel very physical.

ADHD and cardiovascular health

ADHD can influence cardiovascular health indirectly through smoking or nicotine use, sleep difficulties, inconsistent routines, diet, missed appointments, difficulty taking long-term medication consistently and increased risk of some forms of substance misuse. Recognising these patterns can make prevention more realistic and accessible.

ADHD medication and the heart

Stimulant medications such as methylphenidate and lisdexamfetamine can cause modest increases in heart rate and blood pressure in some people. Before treatment, clinicians generally assess cardiovascular history, relevant family history, blood pressure, pulse and cardiovascular symptoms. Pulse and blood pressure are monitored during treatment.

An ECG is not automatically required for everyone starting ADHD medication. Further cardiac assessment depends on the individual’s history, symptoms and examination findings. Nicotine, caffeine, prescribed stimulants and recreational stimulants can also have additive cardiovascular effects.

When to seek urgent help

For persistent but non-emergency symptoms such as recurrent palpitations, breathlessness, dizziness or reduced exercise tolerance, arrange medical assessment.

At a glance

Reliable further information

For current UK guidance and patient information, useful sources include

• NHS - Cardiovascular disease: nhs.uk ↗
• British Heart Foundation: bhf.org.uk ↗
• NICE - Cardiovascular disease: risk assessment and reduction, including lipid modification (NG238): nice.org.uk ↗
• NHS - Coronary heart disease prevention: nhs.uk ↗

This page is for general educational purposes and is not a diagnostic tool. Individual symptoms, risk factors and treatment decisions should be discussed with an appropriate healthcare professional.