What Causes Blood Pressure To Fluctuate?

As a key vital sign, blood pressure can reveal a lot about your health. For that reason, it's helpful to regularly monitor your blood pressure if you have any concerns that it might not be within a healthy range. However, many people find that once they start monitoring their blood pressure, it fluctuates quite a bit. Like many medical conditions, this could be perfectly normal, or it could be cause for concern. Understanding the cause of blood pressure fluctuations, known as labile hypertension, and how to control them will help you determine whether you need to seek medical attention.

What is blood pressure?

As your blood moves through your body, it exerts pressure on the walls of the arteries and veins that it passes through. The exact cause for the most common type of high blood pressure, called essential hypertension, is not fully known.  However, the blood vessels tend to become stiffer with age and contribute to higher blood pressure readings. Because high blood pressure creates a risk of many cardiovascular problems, the cyclical increase in blood pressure is a problem.

While high blood pressure gets a lot of attention due to the danger it poses, low blood pressure can also be a problem. Low blood pressure that's too low can result in dizziness, lack of concentration, fatigue, dehydration, and other health issues. It can also be a sign of underlying health problems, such as heart problems, endocrine problems, infection, or allergic reactions.

Paying attention to causes of blood pressure fluctuations can minimize them and help reduce the problems associated with either extreme.

What can cause blood pressure to fluctuate?

If you notice your blood pressure fluctuating, it can be helpful to understand the possible causes. This will give you some clues as to whether or not your actions are causing the fluctuations, so you can take steps to rule them out as a reason for the fluctuations. If you have drastic changes in your blood pressure that can't be explained, you should consult a medical professional to look deeper into what could be causing it.

Conditions that are easily controllable

We've broken them up into easily digestible sections because there are various risk factors and causes for variations in blood pressure readings. This section will discuss the potential causes that are mostly within your control. These will be the easiest to rule out as possible reasons for fluctuations by making lifestyle modifications.

Eating foods with sodium

Sodium intake is known to affect blood pressure¹ levels. Those with hypertension should avoid consuming too much sodium, as it raises blood pressure. If you generally don't eat a lot of sodium, and your blood pressure spikes coincide with an increased intake of sodium, try removing it from your diet and see if your readings normalize.

Caffeine or alcohol consumption

Aside from medication, caffeine² and alcohol³ are two of the most widely consumed substances that can raise your blood pressure. Because most people aren't under the effects of either drug all day, every day, the spikes caused by them and the subsequent return to normal could be the cause of your blood pressure fluctuations.

Consumption of other drugs and medications

Other drugs that may be less commonly used but can still cause changes in your blood pressure include common over-the-counter (OTC) drugs such as certain nasal decongestants and illegal drugs like cocaine and methamphetamine.

Many prescription drugs can also cause increases or decreases in blood pressure. Your doctor or pharmacist will help you determine whether this is the case for any medication you're currently taking.

Using tobacco products

By now, most people are aware of the risk smoking brings to your lungs. However, many are unaware that smoking tobacco will also cause your blood pressure to rise. This increase is mostly caused by the nicotine⁴ in tobacco and therefore applies to any smoking alternatives that contain nicotine, such as vaping, chewing tobacco, or nicotine patches and gums.

Exercise

Overall, exercise is excellent for your heart health. Regular exercise will help to reduce and stabilize your blood pressure over time. However, as your heart begins to beat faster to keep up with the intensity of your workout, your blood pressure will rise. For some people, this increase in blood pressure can be substantial⁵. After the workout, your blood pressure should return to baseline.

Largely unavoidable conditions

The causes of blood pressure fluctuations listed below are things that we can't readily eliminate in the way we can with the examples in the previous section. However, you can minimize many of those issues through lifestyle changes. Understanding these issues and comparing them to your blood pressure results will help determine whether they may cause fluctuations.

Circadian rhythms

Your body's sleep pattern affects blood pressure⁶. As you sleep, your blood pressure tends to be lower because you are more relaxed. As you awaken, it will rise again. These fluctuations occur in a relatively predictable pattern as you move throughout your sleep-wake cycle. This is one of the reasons that it's a good idea to take your blood pressure at the same time every day.

The temperature

Changes in blood pressure can occur due to the temperatures that people are exposed to⁷. Blood pressure tends to rise when the body is exposed to colder weather and lower when exposed to warmer weather. Because short-term temperature changes don’t have a statistically significant effect on blood pressure, these changes are mostly seasonal in nature.

Stress

Getting angry or stressed isn't good for your mental well-being, but it can be bad for heart health as well. Increases in stress cause your blood pressure to rise⁸, and as you calm down, your blood pressure will return to normal. 

Obstructive sleep apnea

Obstructive sleep apnea (OSA) can also affect blood pressure. An OSA episode can cause blood pressure to remain elevated at night⁹ when it would otherwise drop during sleep. This high blood pressure will stay after waking and starting the day for some people. For others, it will return to normal, which could explain certain fluctuations in your readings.

Diabetes

Diabetes and high blood pressure are two conditions often experienced together. Part of this is because both diabetes and hypertension share similar risk factors. However, some mechanisms in the body that are triggered by elevated blood sugar can also increase blood pressure¹⁰. Therefore, blood pressure readings may fluctuate along with blood sugar levels.

A full bladder

Holding in the need to urinate until your blood pressure reading can result in the reading being higher than it would otherwise be. A full bladder has been shown to increase blood pressure¹¹. The pressure returns to normal as soon as the bladder is emptied but can remain elevated during the entire time it's being held in.

Conditions that only affect some people

The final two conditions are things that don't happen to everybody but are worth mentioning in case you're one of the people who experience them. Both of the related conditions can make it harder to accurately diagnose hypertension.

Being at the doctor's office

We mentioned stress being a cause of increased blood pressure earlier. White coat hypertension, or white coat syndrome, is a particular instance of that effect that's worth mentioning on its own. Some people get so nervous about being at the doctor's office that their blood pressure rises due to the stress of the visit¹². For some people, this can explain why a blood pressure reading is always high at the doctor's office but never at home.

Not being at the doctor's office

Surprisingly, the opposite effect of white coat hypertension can also occur. Masked hypertension¹³ is when your blood pressure appears normal during your doctor's visit but becomes high afterward. Because most people who aren't diagnosed with high blood pressure don't check their pressure at home, it is less commonly caught.

How to prevent big fluctuations

Now that you've seen some causes and risk factors that can cause blood pressure jumps in one direction or the other, let's take a brief look back at the problems and how you can control them. Following these tips will help stabilize your blood pressure if you move far from normal too frequently. If your readings are fluctuating wildly, or if these tips don't help stabilize them, you should consult a medical professional to see what other factors may be at play.

Practice stress management

Decreasing the frequency and intensity of stress in your life can prevent rises in blood pressure that are outside of normal bodily functions.

Dietary changes

Eliminating sodium, caffeine, alcohol, and certain other foods that are known to cause a temporary increase in blood pressure will help stabilize readings.

Be careful with over-the-counter medication

Because certain medications can cause blood pressure increases, you should eliminate them as a possibility when evaluating fluctuations.

Exercise regularly

Although exercise itself can cause blood pressure fluctuations, the long-term benefits of keeping your readings at healthy levels are worth making it a part of your routine.

Keep an eye on your blood sugar

Because increased blood sugar can also result in increased blood pressure, you should try to keep your levels under control when evaluating fluctuations in blood pressure.

Take blood pressure medicine correctly

The purpose of blood pressure medication is to change your blood pressure levels. Taken correctly, they'll result in a healthy, even pressure. However, when taken in the wrong doses or inconsistently, they can result in fluctuations.

Use a correct and consistent cuff size

Although not related to your actual blood pressure, the wrong size cuff can give false readings, and switching cuff sizes will indicate fluctuations that don't exist.

The dangers of fluctuating blood pressure

Your body is meant to operate with blood pressure at a normal level. While we've discussed the complications that can occur if it gets too high or too low, there are also problems associated with blood pressure that varies too wildly. If you haven't been able to reduce your fluctuating readings,  a doctor can help you take steps to avoid these problems.

Heart disease

Researchers use the changes in blood pressure observed over multiple visits to the doctor to study the effects of wildly varying blood pressure on the body. One study found¹⁴ that visit-to-visit variability was associated with an increased chance of heart disease, stroke, and heart failure. The condition was also associated with higher mortality rates.

Dementia

Another study of visit-to-visit variability¹⁵ was done with people of an age that puts them at risk of dementia. The study found that fluctuating blood pressure was likely to cause an increase in the chances of developing dementia.

Masking other conditions

A blood pressure reading that varies too much can also be a symptom of other underlying conditions. Often, blood pressure variation will go from normal to high. If the pressure bounces back and forth between low and high, it could be a sign of a condition known as autonomic dysfunction¹⁶. If you find your blood pressure is dipping low as well as high, you should consult with a doctor.

Treatment for fluctuating blood pressure

In most cases, variations in blood pressure aren't extreme enough to cause concern. If you track your blood pressure over time, your doctor will be able to determine whether the numbers are within a safe range. If they're not, you'll first be asked to make certain lifestyle changes like the ones mentioned above. Your doctor will be able to provide specifics about your lifestyle that may contribute to the fluctuations. If lifestyle changes don't work, they may put you on medication.

The lowdown

With heart disease being a leading cause of death, keeping an eye on unusual blood pressure activity is an important part of maintaining your health. While minor fluctuations are normal, wilder changes in your blood pressure are something you should ask a doctor about. Diet and lifestyle changes can play a big role in keeping your blood pressure at healthy and consistent levels.