Dr. Alessandro Giardini
.png){kind=small}
.png){kind=small}
.png){kind=small}
%20(2)%20(1).png)
A single raised reading does not make a diagnosis. Blood pressure in children changes with age, height, and sex, and the circumstances of the measurement matter enormously. That distinction is very important.
The scenario Dr Giardini encounters most frequently at his London clinics is a parent who arrived having already compared their child's reading against an adult normal range. Adult thresholds simply do not apply. Reassurance, in most of these cases, requires nothing more than a properly timed measurement using the right cuff size and an age-specific chart.
Where genuine hypertension is present, it is very treatable. Most children do not need medication. Early assessment establishes the cause, rules out conditions that need attention, and gives families a clear plan rather than prolonged uncertainty.
The medical term is hypertension. In children under 13, blood pressure is defined as high when it reaches or exceeds the 95th centile for age, sex, and height on at least three separate measurements. For teenagers aged 13 and over, the threshold aligns with the adult definition: 130/80 mmHg or above.
Centile thresholds exist because a child's cardiovascular system is still developing. A systolic reading of 100 mmHg is entirely normal at age four and would fall well below average in a fifteen-year-old. This is why the blood pressure reference chart on this site, which provides normal ranges for boys and girls by age, is a more useful first tool than any adult comparison.
Between confirmed hypertension and normal lies the elevated range, corresponding to the 90th to 94th centile. Children in this band need monitoring and often lifestyle advice, but not yet the full investigative workup triggered by confirmed hypertension.
The most common explanation for a raised clinic reading is the most benign. Anxiety during a medical appointment consistently raises blood pressure, and children are particularly susceptible. A child who was frightened by the cuff, who sat tensely in the waiting room, or who had just been active before their name was called is likely to produce a reading that does not reflect their true resting blood pressure. This happens often. Multiple measurements taken on separate visits, or a 24-hour monitor worn during normal daily life, usually resolve the question quickly.
Studies suggest white coat hypertension accounts for a substantial proportion of initial elevated readings in children referred for specialist assessment. The figure in some paediatric series exceeds 40 per cent.
When no underlying cause is found, the diagnosis is primary hypertension. This is now the most common form in teenagers, largely tracking the rise in childhood obesity and sedentary behaviour over the past two decades. A family history of hypertension substantially increases the risk. Other contributing factors include high dietary salt intake, poor sleep, chronic stress, and insulin resistance. Primary hypertension is manageable, and lifestyle changes alone produce meaningful blood pressure reductions in many affected adolescents.
A secondary cause is more likely the younger isthe child. Below the age of six, a specific underlying condition should be actively sought before assuming hypertension is primary. Kidney disease is the commonest secondary cause in children and accounts for the majority of cases in younger age groups. Other recognised causes include coarctation of the aorta, overactivity of the thyroid or adrenal glands, obstructive sleep apnoea, and certain medications. Both steroids and stimulant medications used for ADHD can raise blood pressure as a side effect.
Most children with hypertension have no symptoms at all. This is precisely why it is sometimes described as a silent condition, and why routine blood pressure checks at every GP appointment and school health review matter. When symptoms do occur, they most commonly include headaches, particularly on waking, dizziness, visual disturbance, fatigue, and in some children, nosebleeds or palpitations. These are non-specific and easy to attribute to other causes, which is part of why childhood hypertension is frequently detected incidentally.
Very high blood pressure can produce more alarming symptoms that require urgent assessment. Severe headache combined with vomiting, confusion, visual symptoms, weakness, or collapse should prompt immediate medical attention and not a wait-and-see approach.
Not every raised reading warrants the same response. The following gives a practical framework, though it does not replace clinical assessment.
A single mildly raised reading in an otherwise well child who was anxious or recently active is usually reassuring. Repeated monitoring and a repeat clinic visit are appropriate. No additional investigation is typically needed at that stage.
Repeated elevated readings across more than one visit, a strong family history of hypertension or stroke, childhood obesity, sleep problems, headaches, dizziness, an abnormal ECG, a heart murmur, or an underlying kidney condition all warrant specialist paediatric review and further investigation rather than simple reassurance and observation.
Urgent medical attention is needed when blood pressure is very high, when there are symptoms such as severe headache, vomiting, visual disturbance, chest pain, breathlessness, confusion, seizures, weakness, or collapse. These features suggest blood pressure has reached a level affecting the organs and require same-day assessment rather than a routine referral.
Blood pressure measurement in children is surprisingly prone to error. The wrong cuff size, a rushed setting, or a child who was not rested before measurement can each produce a misleading result. These details matter more than most parents realise.
The single most useful investigation for suspected hypertension in children is ambulatory blood pressure monitoring (ABPM). The child wears a small, lightweight cuff connected to a portable recorder for 24 hours. The monitor takes readings automatically every 15 to 30 minutes throughout the day and during sleep. That record reveals whether hypertension is genuine across a normal day, whether blood pressure dips appropriately overnight as it should in a healthy cardiovascular system, and whether the clinic reading was simply an anxiety response. ABPM is now strongly recommended before making a diagnosis of hypertension in children and before starting treatment.
In his consultations at Great Ormond Street Hospital and across his private clinics in London, Dr Giardini performs an ECG and echocardiogram when the blood pressure pattern suggests genuine hypertension, when a heart murmur is present, or when there is any clinical concern about early organ involvement. The echocardiogram is particularly important because persistent hypertension can cause the left ventricle, the heart's main pumping chamber, to thicken as it works harder against elevated pressure. This is called left ventricular hypertrophy, and detecting it early changes management. Dr Giardini performs and interprets every echocardiogram himself, so findings are discussed with families immediately in the same appointment.
Blood tests assess kidney function, electrolytes, cholesterol, blood glucose, and thyroid and endocrine function when indicated. A urine test checks for protein and blood, which may signal kidney involvement. A kidney ultrasound is added in younger children or when renal disease is suspected. The precise combination of tests depends on the child's age, the likely cause, and the clinical picture.
For the majority of children and teenagers, particularly those with primary hypertension, treatment begins without medication. Reducing dietary salt, improving the overall quality of nutrition, increasing physical activity, addressing excess weight, improving sleep, and reducing sugary drinks and processed foods all contribute meaningfully. These changes can produce sustained reductions in blood pressure in many adolescents without the need for pharmacological treatment. Progress is reviewed over three to six months before escalating management.
Some children require antihypertensive medication, particularly when blood pressure is significantly elevated, when there is evidence of organ involvement, when symptoms are present, or when lifestyle measures have not produced sufficient reduction after a fair trial. The choice of medication depends on the likely cause and the child's age. Commonly used classes include ACE inhibitors, angiotensin receptor blockers, calcium channel blockers, and thiazide diuretics. These are well tolerated in children when prescribed and monitored appropriately. Dr Giardini initiates, adjusts, and reviews medication individually for each child, with regular blood pressure monitoring and checks of kidney function and electrolytes as part of ongoing care.
Almost always, yes. Exercise is not only safe for children with mildly elevated or well-controlled blood pressure but actively encouraged as a component of treatment. Regular aerobic activity improves blood pressure over time and supports weight management, both of which are beneficial.
The only children who may need temporary restriction from very intense competitive sport are those with significantly elevated blood pressure that is not yet controlled. Once blood pressure is stabilised with treatment, sport can almost always resume. Dr Giardini provides individualised guidance for each child at the time of consultation, taking account of the specific blood pressure level, the underlying cause, and the child's cardiac assessment.
The outlook is very good when hypertension is identified early and managed properly. Most children with primary hypertension improve substantially with lifestyle change. Others require medication for a period. A minority will need longer-term treatment, particularly those with an underlying secondary cause that cannot be fully corrected.
The important point is that the risks associated with childhood hypertension, including early cardiovascular disease and kidney damage in adult life, are substantially reduced by early detection and appropriate management. With proper assessment and follow-up, most children with hypertension grow into healthy adults with excellent long-term outcomes.
No. A single elevated reading is not sufficient to diagnose hypertension in a child. Most guidelines require elevated readings on at least three separate occasions before a formal diagnosis is made. A single raised reading in clinic frequently reflects anxiety, recent activity, or measurement error rather than true hypertension.
Yes, and this is one of the commonest explanations. White coat hypertension, in which blood pressure is elevated in medical settings but normal in everyday life, accounts for a substantial proportion of raised readings in children referred for assessment. A 24-hour ambulatory blood pressure monitor worn at home and school resolves the question effectively.
Normal blood pressure in children depends on age, sex, and height. There is no single figure that applies across all children. The reference table on this site provides normal ranges for boys and girls from age one to seventeen at the 50th height percentile. Your child's reading should be interpreted against the appropriate column for their age and sex.
Younger children are more likely to have an underlying cause, such as kidney disease, coarctation of the aorta, or a problem with the adrenal or thyroid glands. Below the age of six, a secondary cause should be actively investigated rather than assumed absent.
Yes. Excess weight is now one of the commonest drivers of primary hypertension in teenagers. The relationship is well established, and weight loss combined with dietary and lifestyle changes can produce sustained reductions in blood pressure in many affected young people.
An echocardiogram is recommended when hypertension is confirmed, when a heart murmur is present, when the ECG shows any abnormality, or when there is clinical concern about heart muscle thickening. Dr Giardini performs both the ECG and echocardiogram at the same appointment, with findings discussed immediately.
An ambulatory blood pressure monitor is a small device worn on the upper arm for 24 hours. It inflates automatically every 15 to 30 minutes, recording blood pressure during normal daily activities and during sleep. It is the most accurate way to confirm whether a child's blood pressure is genuinely elevated, or whether the raised reading in clinic was caused by anxiety.
Yes. Stimulant medications including methylphenidate and amphetamine-based medicines can cause modest increases in heart rate and blood pressure. Blood pressure should be checked before starting any stimulant medication and monitored regularly during treatment. A dedicated guide to cardiac screening before ADHD medication is available on this site.
Persistent untreated hypertension can affect the heart, kidneys, and blood vessels over time, increasing the risk of cardiovascular disease and kidney damage in adulthood. Early detection and appropriate management substantially reduces these risks. Most children with properly assessed and managed hypertension have an excellent long-term outlook.
Seek urgent medical attention if high blood pressure is accompanied by severe headache, vomiting, visual disturbance, confusion, chest pain, breathlessness, weakness, seizures, or collapse. These features suggest a hypertensive emergency requiring same-day assessment. For non-urgent concerns, contact your GP promptly rather than waiting for a routine review.
Author: Dr. Alessandro Giardini, MD, PhD
Written 14/05/2026