Why you keep getting different blood pressure readings

Why you keep getting different blood pressure readings

Blood pressure is an important indicator of your health as it measures the force of blood flowing through your blood vessels. While you probably know it’s important, you might not know why your blood pressure readings vary each time.

“It’s actually quite normal to have variation in blood pressure readings, even within a few minutes,” says Marjorie Willett, a nurse practitioner at Aurora Health Care. “Factors that may create changes include physical activity, emotion, diet (especially salt and alcohol intake), and sleep deprivation.”

Here are the top three reasons for blood pressure reading fluctuations:
  • Time of day: Blood pressure has a daily pattern. Usually, it starts to rise a few hours before a person wakes up. It continues to rise during the day, peaking in midday. Blood pressure typically drops in the late afternoon and evening.
  • Different equipment: The equipment used can also impact the readings. If you’re using a home blood pressure cuff, the readings might be off. The same holds true for drugstore equipment.
  • Stress levels: If you are feeling strong emotions or anxiety, or even just feeling stress because you are in a health care setting, your readings may vary.
Most fluctuations in blood pressure readings are within the ranges outlined in blood pressure categories:
  • Normal blood pressure: Less than 120/80.
  • Elevated blood pressure: Readings consistently run 120-129 systolic and less than 80 diastolic.
  • Hypertension stage 1: Blood pressure consistently runs 130-139 systolic or 80-89 diastolic.
  • Hypertension stage 2: Blood pressure consistently runs 140/90 or higher.
  • Hypertensive crisis: Blood pressure readings exceed 180/120 and you have symptoms such as headaches, chest pain, nausea/vomiting or dizziness. If this occurs, seek medical attention immediately.
Is it a concern if blood pressure readings vary between arms?  

“A systolic difference of more than 20 points could potentially indicate a problem,” says Willett. “Blood pressure variance can be due to a circulatory disturbance in the arterial structure that supplies blood to the arm. Further assessment by your provider would be recommended and additional testing may be necessary.”

Despite the variations, keeping an eye on your blood pressure is a good idea.

“If left undetected or uncontrolled, prolonged high blood pressure, or hypertension, can lead to stroke, heart attack, heart failure, kidney disease, peripheral arterial disease, vision loss and sexual dysfunction,” says Willett. “Many people don’t even realize they have hypertension because it doesn’t frequently cause symptoms. That’s why it’s referred to as the ‘silent killer’.”

Take a free online quiz to learn about your risk for heart disease.

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  1. Why does office visits aides have the arm lower than the heart when taking my blood pressure . Does it matter?

  2. I was told your arm should be held enligned with your heart while checking your pressure reading!!

  3. I was told to have your pressure taken on a bare arm..not over clothing.

  4. Charlotte Serazio May 6, 2024 at 11:45 pm · Reply

    Battery charged blood pressure machines which are often used in physician’s offices tend to lose their charge as the day wears on and hence losing accuracy as the day progresses. Take that into consideration also if you are having eradict blood pressure readings. A good nurse or medical assistant should be able to tell you if it is. battery charged once a day and take that into consideration with your readings. I learned this by opening my mouth and asking about it! Some offices have poor and/or old machines which can dramatically affect your BP readings…don’t be too quick to have an invalid reason for taking BP meds!!!

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About the Author

Annette Guye-Kordus
Annette Guye-Kordus

Annette Guye-Kordus is a public affairs coordinator with Advocate Health Care and Aurora Health Care.