• Typically, blood pressure slightly falls when someone stands up.
• However, for some people, blood pressure increases after standing up.
• A new study finds that the latter may indicate a higher risk for adverse cardiovascular events.

A recent study in Hypertensionexamined the difference in blood pressure readings in young to middle age people when they were lying down versus standing.

The researchers investigated how this might have links to long-term adverse health outcomes.

They found that participants who had a higher blood pressure when standing compared with lying down had a greater risk for cardiovascular and renal events later in life.

What is blood pressure?

Blood pressure is the force with which blood pumps through the body. Doctors measure it using two numbers: systolic and diastolic readings. The systolic reading is the pressure when the heart contracts, while the diastolic reading is the pressure on blood vessels when the heart relaxes.

A healthy blood pressure reading is 120/80 milligrams of mercury (mm Hg) or lower. People with a systolic reading greater than 140 mm Hg or a diastolic reading greater than 90 mm Hg have high blood pressure, or hypertension.

High blood pressure increases the risk of developing other health problems. For example, the condition can contribute to heart, brain, eye, and kidney damage.

Anyone can have high blood pressure, and the number of young- and middle-aged people with this condition is growing.

Standing versus lying down

Typically, when medical professionals take a blood pressure reading, the person stays in one position, usually sitting or lying down.

However, they will sometimes take readings in more than one position, usually to test for drops in blood pressure when moving from lying down to sitting or standing. If it drops significantly, healthcare experts call it orthostatic hypotension.

In some people, blood pressure can increase when transitioning from sitting to standing.

The authors of the current study wanted to determine if people who had higher blood pressure standing versus lying down were at a greater risk for adverse cardiac and kidney problems. Study author Dr. Paolo Palatini explained the following to Medical News Today:

“Up to now, doctors measured [blood pressure] on standing only in [older adults] on pharmacological treatment with the purpose of detecting orthostatic hypotension. In young to middle age people, [blood pressure] is currently measured only in the lying or the sitting posture.”

Study breakdown and results

The researchers conducted the study in Italy and involved 1,207 participants aged 18–45 years. All these individuals had hypertension but had never received treatment.

To collect baseline data, the scientists had each participant undergo a physical exam. They also looked at factors, such as body size, and took blood and urine samples.

The researchers asked participants questions about their personal and family history and physical activity levels. They also noted participants’ use of cigarettes, alcohol, and coffee.

They took three blood pressure measurements while each participant was lying down. Next, they took three measurements while each was standing. They then looked at the difference between standing blood pressure and lying blood pressure. They took the measurements twice, 2 weeks apart.

The team referred to participants with a systolic blood pressure increase of greater than 6.5 mm Hg as “hyperreactors.” These hyperreactors also had higher levels of epinephrine in their urine.

Over several years, the researchers followed up with participants and collated information about any major adverse cardiovascular events (MACE).

They concluded that a hyperreactive rise in blood pressure upon standing has links with a higher risk of MACE in people with hypertension.

Individuals in the top 10% of the hyperreactive group were twice as likely to experience MACE than those with a typical blood pressure response to standing.

When asked to comment on the study, Prof. Bernard Cheung, Ph.D., FRCP, Sun Chieh Yeh Heart Foundation Professor in cardiovascular therapeutics at the University of Hong Kong, offered the following insight:

“People with this response [the change in blood pressure from lying to sitting] tended to have higher epinephrine levels in their urine. The authors, therefore, suggested that the exaggerated blood pressure response might be explained by increased epinephrine secretion, which makes sense because this stress hormone is known to be a trigger of cardiovascular events.”

“This concept is novel,” he continued, “and if true, the lying–standing change in systolic blood pressure could be a simple bedside test that can join the known predictors of [cardiovascular events].”

Study limitations and continued research

The authors noted several limitations in their study. Firstly, the research only included white participants, so it is unclear how much of the data applies to other groups. Additionally, more men participated in the study than women, so results may not be equally applicable for other genders.

Prof. Cheung also offered the following words of caution:

“There were findings that were difficult to explain. For example, the pulse rate increased by an average of only one beat per minute on standing in the hyperreactive group. One would expect a higher pulse rate if there is increased epinephrine output.”

“Also,” he continued, “people with an exaggerated blood pressure response to standing were surprisingly less likely to be treated with antihypertensive drugs. It seems that further study is required before incorporating the lying–standing systolic blood pressure as a cardiovascular risk factor.”

Dr. Palatini explained to MNT:

“Measuring [blood pressure] on standing after the patient has been lying on the bed is a very simple and costless maneuver that every doctor should do in [their] office. If the patient has a systolic [blood pressure] increase greater than 6–7 mm Hg, this patient is at high risk of cardiovascular events.”

“Why? Because many people spend part of their daytime performing activities while they are standing up and thus their [blood pressure] will be, on average, higher than the one in the lying [or] sitting posture. In addition, their high reactivity to standing means that they are likely to be hyperreactive also to other stimuli of daily life.”

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