Teenagers often experience dizziness or faint after a sudden shift in body position. These symptoms tend to aggravate while standing for extended periods of time, for example, at a graduation ceremony or in the summer heat. Most of the time, however, it is not blood pressure or a more serious condition that may cause them to feel lightheaded; what they experience is an adaptation failure of the cardiovascular system.

From a growth viewpoint, there are two critical periods in our lives. One is right after birth, the other is during puberty when teens may average out several centimeters’ growth in one summer.

The problem is that the cardiovascular system sometimes have a hard time keeping up with those growth spurts – even if it is supposed to adapt to swift changes

– says Attila Szabó, pediatrist, hypertonologist, head of Department of Pediatrics, Semmelweis University.

It is due to this “lag” that dizziness and fainting are more common in adolescents than in adults – especially those with a thin frame who often get a low blood pressure reading. “If not sufficient blood is pumped to the central nervous system, our blood pressure drops and we get into a presyncope state” – he adds.

This vegetative nervous system malfunction tends to occur more around this time of the school year when teenagers stand long hours at one place during a school ceremony. What happens is that peripheral vessels enlarge in the heat, blood collects in the leg and not enough blood is flowing to the central system. Since the body is focusing on maintaining vital functions, it is unable to control the blood flow properly.

It is important to note that this is an adaptation malfunction, not hypertension, and not a condition per se

– Szabó says. Once the cardiovascular system gets in synch with the growth, symptoms arise less frequently, he adds.

It is normal for blood pressure to have a daily fluctuation – generally, it is 10% higher during the day than at night. Weather tends to impact it to a certain extent as well – both in adults and adolescents – but it doesn’t usually cause severe symptoms.

Discernment at this age is key though: with frequent readings (every 24 hour if there is a risk for high blood pressure) one can establish whether it is hypertension or an adaptation malfunction.

With that, hypertension is becoming ever more frequent among adolescents. A condition of the adult and elderly, high blood pressure in children used to be related to other health issues –  mostly kidney disease, hormonal or cardiovascular disorders. Today, however, the main reason is obesity, Szabó says. 

One in every four children in Europe is overweight or obese. Smoking, even passive, and a diet high in sodium are also risk factors. If salted nuts, chips, fast food or sugary drinks such as coke or energy drink are consumed on a daily basis, children are more likely to develop hypertension.

A family history of high blood pressure, including parents who developed high blood pressure at an early age, needs more follow up as it has been linked to a higher risk of being developed in children as well, the expert warns.

Measures carried out properly – seated, in a relaxed position with a cuff embracing two-thirds of the upper arm – can help diagnose high blood pressure. Cuffs that are too small/snug or too big/loose, or placed on the wrist can result in a faulty reading.

Detecting hypertension early on may not be easy as there is not a set value for children, Szabó notes. Depending on the age, weight, height and even race, it can vary. For small children, it should not exceed 90-100/50-60 mmHG. For adolescents, it is closer to the 120/80 mmHG set for the adult population. Pulse rate also varies by age; for infants, a rate above 100 bpm is normal, while for adults a near-100 bpm reading can be a sign of a heightened state (with 60-100 bpm being the normal).

For example, a 5’3 tall gymnast aged 17-18 and a 6’4 tall basketball player will have different baseline measurements. The taller someone is, the more pressure it takes to pump blood to every part of their body therefore a reading for a nearly 6’5 boy will be higher than that of a shorter athlete.

Teenagers should see a doctor when they experience symptoms linked to high blood pressure or when get a high value reading while they have a headache. They should also consult with a pediatrist if dizzy periods/fainting occur often and don’t decrease in frequency.

The likelihood may be low but there is a possibility that it is not an adaptation failure but arrhythmia, the professor highlights.

Photo: Balint Barta -Semmelweis University