High blood pressure, also known as hypertension, is usually thought of as an adult health issue. But doctors are now raising serious concerns after a study published in The Lancet Child & Adolescent Health in November 2025 showed that rates of high blood pressure among children and teenagers have nearly doubled over the past two decades.Blood Pressure In UK: The Lancet Study and Why Doctors Are Concerned in the UKHypertension has long been associated with people in their 30s and 40s, often linked to work stress and ageing. Today, however, shifts in daily habits and increasingly inactive lifestyles mean the condition is appearing more often in children and adolescents too. For years, young people were largely overlooked in discussions around blood pressure, and routine screening was rarely carried out. As a result, the true scale of the problem remained unclear. UK doctors are now calling for a nationwide testing programme to assess how widespread the issue is and to identify children who may need early support and treatment.What Is Hypertension?Hypertension is the clinical term for high blood pressure. It develops when the force of blood pushing through the arteries remains higher than what is considered healthy over time. Arteries are the blood vessels that carry oxygen-rich blood from the heart to the brain and the rest of the body. High blood pressure is often described as a silent killer because it can cause lasting damage without clear warning signs or symptoms.Blood Pressure: How Is It Diagnosed?Blood pressure is usually checked using a monitor with an inflatable cuff placed around the upper arm. The reading is shown as two numbers, measured in millimetres of mercury, written as one over the other. The top number, known as systolic pressure, reflects the force of blood when the heart beats and pumps blood around the body. The bottom number, called diastolic pressure, measures the pressure in the arteries when the heart relaxes between beats.The definition of high blood pressure varies between countries. In the UK, a normal adult reading falls between 90/60 and 119/79. Readings from 120/80 to 139/89 are considered raised, while 140/90 and above is classed as high blood pressure. In the United States, readings between 130/80 and 139/89 are labelled stage 1 hypertension, with stage 2 beginning at 140/90.Diagnosing hypertension in children is more complex. Blood pressure naturally changes as children grow and depends on age, height, and sex. Rather than fixed numbers, doctors diagnose high blood pressure when a child’s readings fall within the highest five per cent for others of the same age, height, and sex.Blood Pressure In UK: Who Is At Risk?High blood pressure is widespread, particularly among older adults. Around one in three adults in the UK and nearly half of adults in the US live with hypertension. Age plays a key role because arteries gradually lose flexibility and become thicker over time. Family history also matters, as genetics can increase risk. People from Black African, Black Caribbean, and South Asian backgrounds are known to face a higher likelihood of developing the condition.Lifestyle choices also have a strong influence. Diets high in salt, being overweight or obese, lack of regular physical activity, smoking, excessive alcohol intake, and prolonged stress can all contribute to raised blood pressure.What About Children?In babies and very young children, high blood pressure is usually linked to underlying medical issues such as heart defects, kidney disease, or genetic and hormonal conditions. This form is known as secondary hypertension. Since the 1990s, however, rates of high blood pressure among children and adolescents have risen more than fourfold, reaching around six per cent. Poor diets, low levels of physical activity, and increasing rates of overweight and obesity are major factors behind this rise.Why Is Hypertension Harmful?High blood pressure can quietly harm the body for many years before symptoms appear. Constant strain on the blood vessels can lead to aneurysms, where weakened artery walls bulge and may rupture, sometimes with fatal consequences. The heart is forced to work harder, increasing the risk of heart failure. Damage to the inner lining of arteries can trigger inflammation and the buildup of plaques, making blood vessels narrower and less flexible. This restricts blood flow and raises the risk of chest pain, irregular heartbeats, and heart attacks.The kidneys are especially sensitive to high blood pressure. Damaged blood vessels can stop them from filtering waste effectively, potentially leading to kidney failure that requires dialysis or a transplant. The eyes can also be affected, as their delicate blood vessels are prone to damage, causing bleeding, blurred vision, or even blindness.When blood flow to the brain is reduced by narrowed or blocked arteries, it can lead to vascular dementia or mini-strokes. Severe cases may result in major strokes caused by clots or bleeding linked to long-term high blood pressure.In children, hypertension can harm vital organs such as the heart, kidneys, and eyes at an early age. This makes early detection and treatment crucial to protect long-term health.