Is It Normal for Blood Pressure to Fluctuate?

Some variation in blood pressure throughout the day is normal, especially as a response to small changes in daily life like stress, exercise, or how well you slept the night before. But fluctuations that occur regularly over a number of doctor visits may indicate an underlying problem.

In fact, studies have found that a higher visit-to-visit variation in blood pressure is associated with a higher risk of cardiovascular disease and all-cause mortality.

How To Know If Your Blood Pressure Is Fluctuating

First, it’s important to make sure that your blood pressure really is fluctuating. If you’ve made the measurements yourself using home monitoring equipment or the machines commonly found in grocery stores and pharmacies, the changes you’ve seen might actually be related to errors or variations in the measurement process itself.

While home blood pressure monitoring can be an effective and useful tool in some situations, you need proper training to ensure you're using the correct technique, as performing the measurements without this training might explain the variation you see. Drugstore machines—the kind that require you to sit in a chair and put your arm through a cuff—are notorious for being poorly calibrated and fairly inaccurate.

To prevent erroneous reads, it is best to bring in your home blood pressure monitor readings and compare them with the readings in your doctor's office.

Alternatively, some doctors recommend ambulatory blood pressure monitoring in which a device is worn by a person at home. The devices measure the blood pressure over a one- to two-day period every 15 to 20 minutes during the day and every 30 to 60 minutes at night. This is more costly and not always available, so self-recorded home blood pressure measurements are a reasonable alternative.

What Causes a Fluctuating Blood Pressure?

Experts are exploring why blood pressure is variable from visit to visit. It may be that people with fluctuating blood pressures have an underlying blood vessel problem and that their variable readings serve as a marker or clue that they are at a higher risk of having a heart attack or stroke.

Very rarely, fluctuating blood pressure may be due to a pheochromocytoma—a usually benign tumor in the adrenal gland. This is a rare occurrence.

White Coat Hypertension and Masked Hypertension

It's important to distinguish fluctuating blood pressures from two phenomena known as white-coat hypertension and masked hypertension.

In the phenomenon white coat hypertension, a person's blood pressure is considered to be "high" at a doctor's office, but normal when at home. This high blood pressure is attributed to the stress of being in a doctor's office, which is why a nurse will often wait for a person to rest comfortably for five minutes before taking a read. In addition, it's also recommended that two blood pressure reads are taken and repeated if there is a difference of more than 5 mmHg.

Masked hypertension is the opposite and occurs when doctor visit blood pressures are normal but out-of-doctor's office reads are high.

To sort these issues out, a doctor may recommend home monitoring or ambulatory blood pressure monitoring. Home monitoring may also be recommended for:

Persistent high blood pressure readings despite increasing medications
Low blood pressure readings while taking high blood pressure medications

Do You Have Hypertension?

If you notice some high blood pressure reads interspersed with normal ones, it's possible you have hypertension but have not been diagnosed with it. Experts do not know precisely how primary hypertension develops, but it is believed to involve a complex interaction between a person's genes and their environment that affects their heart and kidney function.

That being said, there are clear risk factors or factors that increase a person's chance of developing hypertension like:

Age (the likelihood of developing hypertension increases the older you get)
Family history
Obesity
High sodium diet
Sedentary lifestyle
Excessive alcohol intake
Having other medical problems like diabetes or high cholesterol

Secondary hypertension may arise, too. Secondary hypertension means that a person's high blood pressure develops from another problem in the body or as a result of taking a medication. Examples of secondary hypertension include:

Obstructive sleep apnea
Medication use (for example, NSAIDs and certain antidepressants)
Certain endocrine and hormone disorders (for example, hyperthyroidism)

A Word From Verywell

If you’re sure that the measurements are accurate and the blood pressure swings happen even when you’re relaxed, well-rested, and have no reason that can account for the changes, go see a doctor. The good news is that with proper monitoring, healthy lifestyle habits, and medications (if needed), you can gain control over your heart health.