Fluctuating Blood Pressure and Inconsistent BP Readings

Many people will experience fluctuating blood pressure throughout each day. Fluctuations within normal ranges are perfectly okay and expected to happen. If your blood pressure was not changing during the day, there would be something wrong.

There are many reasons why your blood pressure will go up and down. Some of them are happening no matter what, and others can be avoided. Larger, more than normal fluctuations, can happen too. If they do, it means you may have a medical issue that needs attention from a physician.

This post will inform you of all the fluctuating blood pressure causes, good and bad, and how you can correct some of them. I’ll also tell you complications which can occur from large, consistent fluctuations and treatments to avoid them in the future.

BP Tip: You can lower BP naturally by changing how you breathe. There’s a device approved by the FDA and The American Heart Association. It guides your breathing a few minutes a day which has been proven to lower BP. You can check it out in the manufacturer’s website by clicking here.

Disclaimer: Some links in this article are affiliate links which means I may earn a small commission at no extra cost to you. As an Amazon associate I earn from qualifying purchases.

Fluctuating Blood Pressure Causes

1) Time Of Day

Your blood pressure will rise and fall depending on the time of day. During the night when you’re sleeping, through the day and evening time, you’ll experience different readings.

Blood Pressure While Sleeping

Typically your pressure is lowest during the night while sleeping because your body becomes more relaxed. Blood pressure is normally unaffected by outside distractions experienced during the day. Because of this, it can dip by as much as 10 % to 20%. While in a good sleep, your heart rate and blood pressure will lower.

A drop in blood pressure while sleeping is extremely important. Studies have shown when people have a normal drop in pressure while sleeping, their risk of cardiovascular disease is lower (r).

Blood Pressure Higher or Lower in the Morning

After waking up, your blood pressure will typically start rising higher than when you were sleeping. Your body follows a daily biological cycle which is heightened by surrounding influences like daylight (r). There are other medical reasons, untypical, why this happens which can lead to life-threatening problems. You can read about it in my blog post by clicking right here, High Blood Pressure In The Morning.

Blood Pressure Morning vs Afternoon

Your blood pressure will fluctuate up and down coinciding with your daily activities. The fluctuations may be different for you than others depending on your daily habits. Typically, it will rise the most in the afternoon and then start to drop during the evening prior to sleeping again.

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2) After Eating

Certain food and drink can raise or lower your blood pressure. Foods high in tyramine can cause instant spikes. Tyramine is an amino acid that plays a role in regulating blood pressure (r). Foods high in tyramine include:

  • Alcohol
  • Processed meats
  • Cured meat
  • Aged cheese
  • Fermented or pickled food

I love my coffee in the morning, but unfortunately caffeine can temporary raise blood pressure, which I wrote about here, Does Coffee Raise Blood Pressure. Other foods can have a calming affect and lower it. In my blog post, 10 Drinks To Lower Blood Pressure Backed By Science, I mention how a study which found drinking hibiscus tea lowered blood pressure right after people started to drink it (r).

3) Full Bladder

Having a full bladder can increase your systolic blood pressure as much as 10 to 15 mmHg higher (r). The new blood pressure guidelines recommend measuring it with an empty bladder (r). It’s one of the many mistakes people make when monitoring their pressure at home.

Check out my post which lists all the steps necessary to measure your blood pressure at home. In addition, find out why size does matter, you can read why, right here.

4) Temperature

By entering or leaving a warmer or colder area can cause your blood pressure to fluctuate. Colder temperature can cause your blood vessels to constrict which will raise your pressure. Warmer temperatures or a nice warm bath can lower it. One study showed an increase in temperature by 33 degrees decreased blood pressure (r).

5) White Coat Syndrome

Have you ever felt nervous or anxious when visiting the doctor? You’re not alone, and it can cause your blood pressure to change when walking in for your appointment. This is called white coat syndrome and typically will raise your pressure (r).

6) Masked Hypertension

This is the opposite of white coat syndrome. Blood pressure will be higher when at home instead of at the doctor’s office. If you have either one of these conditions, your pressure may fluctuate leaving or arriving at home or the doctor’s office (r).

7) Exercise

Daily activities, like exercise, can raise your blood pressure. Your body needs more oxygen during exercise because it puts extra demands on your circulatory system and muscles. To get more oxygen to your muscles, your heart will beat faster and harder to circulate blood and oxygen.

Typically, the better shape you’re in, the faster your blood pressure will return to normal. In addition, if you have high blood pressure, the decrease in pressure after exercise may be greater (r). If you have low blood pressure, be careful about which movements you perform. Fast up and down activities can cause dizziness. It’s similar to when you stand up after sitting or lying down.

8) Medical Issues or Conditions

Many different diseases and conditions can cause fluctuating blood pressure. The following can affect it higher or lower:


In the beginning stages of pregnancy, a woman’s circulatory system expands quickly (r). This can cause blood pressure to drop during the day. The following pregnancy related issues can also cause it to fluctuate:

  • Dehydration
  • Infections
  • Internal bleeding
  • Medication
  • Endocrine issues
  • Malnutrition


Diabetes can raise or lower your blood pressure and cause inconsistent readings. If you have nerve damage on internal organs as a result of diabetes, your pressure can change. Swings in blood sugar levels can cause low blood pressure and then reverse back to normal.

Cardiovascular disease

If you have cardiovascular disease, you may be on medication. As you’ll see in the medication section below, different medications, dosages and the time you take it, can cause your blood pressure to fluctuate.

A person with cardiovascular disease may not see the dip in blood pressure while sleeping. Someone with high blood pressure may experience a bigger spike while exercising than someone who doesn’t.

A person who has a clogged artery on one side of their body will likely get different blood pressure readings in each arm. For this reason, measuring it in the correct arm is very important (r). I dedicated a whole blog post on this topic. In it I tell a story of how a woman was misdiagnosed, hospitalized and given medication because of a nurse’s mistake. You can read about it by clicking here.

Other cardiovascular problems that may cause inconsistent readings include:

  • Valve problems
  • Heart Failure
  • Low heart rate

Kidney problems

While high blood pressure can cause kidney problems, the reverse is also true. Unhealthy kidneys can affect your blood pressure and cause fluctuations (r). Your kidneys play an important part in regulating it. Unhealthy kidneys are less able to regulate BP. If kidneys are not removing wastes and extra fluid properly, the extra fluid can cause a spike.

Thyroid Problems

Both hypothyroidism and hyperthyroidism can affect blood pressure levels (r). When the thyroid produces too much hormone, the heart is forced to work harder. This increases the heart rate and blood pressure. When a thyroid is uncontrolled properly, this can cause fluctuations.

Adrenal Glands

The adrenal glands, which sit on top of your kidneys, can produce too much hormone or not enough. When they are not producing enough hormones, adrenal fatigue can lower blood pressure. When they are producing too much cortisol, you may have sudden spikes.


This is a rare condition when a tumor grows on your adrenal glands. It alters hormone production and can cause sudden changes in your BP. This condition will cause fluctuations and inconsistent readings from one moment to the next (r).

Labile Hypertension

Labile hypertension is when the fluctuating blood pressure you have all day long, spikes higher than normal. It can be caused by many of the medical issues listed above or by taking certain medications (r).

9) Medications

All kinds of medication, prescription and over-the-counter, can affect your blood pressure. Your blood pressure can fluctuate right after taking your medication. This is why experts recommend measuring it before taking medication and not right after.

In addition, the wrong dosage can cause fluctuating blood pressure. If you have high blood pressure or you’re on medication, always check with your doctor ahead of time about what are the best OTC medicines for you (r).

The following medications can lower your blood pressure:

  • Antidepressants
  • Medications used for surgery
  • Alpha-blockers taken with high blood pressure medicine like diuretics
  • Parkinson’s disease medicine
  • Erectile dysfunction medication
  • Some OTC medicine like allergy and cold medicine taken in combination with other drugs

The following medications can raise your blood pressure:

  • NSAIDS – Painkillers like Advil, Motrin, Ibuprofen
  • Birth control pills, especially ones higher in estrogen
  • Cold medicines containing stimulants
  • Decongestants

10) Illegal Drugs

Drugs like cocaine are powerful stimulants that constrict your blood vessels. In addition, it can be dangerous and there is an association with strokes, sudden death, hypertensive crisis and seizures. Amphetamines also mimic the affect on blood pressure like cocaine (r). Marijuana, known to relax people, can cause a fluctuation within 20 minutes after smoking (r).

11) Supplements

There are many supplements claiming to benefit your health or blood pressure. I take one myself, you can check it out by clicking here. But prior to taking any supplement, always talk to your healthcare provider. If you already have high blood pressure and take medicine, some of them may do the opposite of what they say. They can also interfere with some medication and make them less effective.

12) Smoking

Long-term effects on smoking and blood pressure are still being studied. Every time someone lights up, it causes blood pressure to increase temporarily (r). A smoker will experience more inconsistent readings throughout the day than most.

13) Dehydration

When your body doesn’t have enough fluids, you may become dehydrated. This can happen anytime during the day especially if you’re losing fluids faster than you can replace them. The decrease of your body’s fluids can cause your pressure to change (r).

Dehydration typically causes blood pressure to drop. The decrease in fluid and blood volume can lower it. Recent research has shown an association with dehydration and high blood pressure as well, although this needs more of a look. While dehydrated, your body releases a hormone called vasopressin. This hormone may cause your blood vessels to constrict (r).

14) Stress

During a stressful situation, your body releases stress hormones, cortisol and adrenaline. This causes your heart to beat faster and blood vessels to constrict which raises your pressure (r).

All day long occurrences that cause stress is one of the biggest reasons for fluctuating blood pressure. No wonder why it typically hits its high during the day. Traffic, work, rude people, rushing to appointments and more cause a roller coaster of ups and downs.

15) Errors and Mistakes Taking Blood Pressure

There are many errors people make while measuring their blood pressure that can cause your readings to fluctuate (r). The different readings can occur between your morning and evening measurements, or even minutes apart from each other. The following are the most common:

  • Crossed legs can elevate blood pressure.
  • Failure to sit upright can raise your blood pressure.
  • Sitting with your back unsupported can increase your measurements.
  • Arm position, which changes the height of the cuff, can raise or lower your BP. Even when arm position is perfect, making one mistake can raise BP by 10%. Read about that mistake in my blog post, Effect Of Arm Position On Blood Pressure.
  • Failure to have 5 minutes of quiet time prior to measuring.
  • Distractions while measuring like talking, texting, watching Tv, browsing social media and similar common activities.
  • As mentioned earlier, measuring BP with a full bladder.
  • Making your cuff too tight or loose can cause inconsistent readings.
  • Wrapping the cuff around clothing and not on your bare arm.
  • Failure to take 2 to 3 readings and average them together.
  • Using an inaccurate home monitor. To determine if your home monitor is accurate, read how in my blog post, right here.
  • Smoking, drinking caffeine or exercising within 30 minutes of taking your measurement.
  • Failure to take your blood pressure the same times every day.
  • Taking a hot or cold bath within 20 minutes of measuring your BP.

Fluctuating Blood Pressure Complications

Just because you have fluctuations in blood pressure, it doesn’t always mean you have a bigger health problem. Although they may be a warning sign of future complications. The following are some of them:

Heart Disease

Studies have shown, people with blood pressure fluctuations were more likely to develop cardiovascular disease more than people who had normal pressure (r). Addition research showed a link with inconsistent blood pressure and cardiovascular issues (r).

High Blood Pressure

People with blood pressure spikes throughout the day may develop high blood pressure over time.


A study showed people who experienced fluctuating blood pressure were twice as likely to develop dementia when they were older (r). Another study showed a link between blood pressure fluctuations and declines in memory and cognitive ability (r).

Fluctuating Blood Pressure Treatments

To diagnose why you have fluctuating blood pressure, your doctor may recommend 24 hour blood pressure monitoring. This is done with an ambulatory blood pressure monitor. You’d wear a cuff around your upper arm connected to a monitor you can attach to your body or clothes. These typically measure your pressure 3 times an hour during the day and once an hour while sleeping.

After diagnosis, your physician will want continued home monitoring but with your own machine. You can check out 3 home monitors I recommend in my blog post right here. In addition to home monitoring, the following are some treatments that will be recommended:

Improve Stress Reduction

  • Find better ways to deal with unavoidable stress.
  • Stay clear of stress that can be avoided.
  • Practice relaxation techniques like breathing exercises, meditation and self-massage.

Avoid Unhealthy Habits

  • Illegal drugs
  • Excess alcohol
  • Smoking

Physical Activity

    • Try getting 20-30 minutes of physical activity every day.
  • Yoga
  • Walks
  • Jogging
  • Cardio

Nutrition and Eating Habits

The suggested eating habits for fluctuating blood pressure are the same for high blood pressure. It’s pretty simple and not hard to do, just reduce the foods that help contribute to high blood pressure and eat the foods beneficial for BP. I have a blog post on each one in complete detail which you can…

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Kevin Garce

Kevin Garce is a Certified Health Coach who encourages people by informing them on blood pressure topics important to them. His years of research and knowledge inspire people to achieve their goals. Read more here About Me

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