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What can affect Blood Pressure Readings? (Top 10 Factors)

What can affect Blood Pressure Readings? (Top 10 Factors)

Vitals like blood pressure readings are ever-changing in the human body. But for some reason, you can find them abnormally high or low. The important thing to consider here is, the reading can be false and the abnormality is influenced by external factors. It doesn’t necessarily indicate a health issue. So, what can affect blood pressure readings? Let us discuss the major factors and know how to avoid a false reading.

Factors Influencing Blood Pressure Readings

ADC Blood Pressure Monitor

Blood pressure readings can be influenced by [1],

  • Emotional State of the Patient
  • Absence of Comfortable room temperature
  • Uncalibrated Reading device
  • Improper Cuffing
  • Not relieving a full bladder
  • Certain medications
  • Involving in physical activity
  • Talking
  • Unsupported Arm
  • Smoking

Emotional State of the Patient

Emotional well-being and a state of calmness are very important to determine accurate blood pressure readings. It is recommended to keep the patient at rest and calm them before taking readings [2]. You can have a 5 to 10mmHg difference in readings if the emotional state of the patient is not stable.

Uncomfortable Room Temperature

Uncomfortable room temperature can influence blood pressure significantly [2]. You need to keep the room temperature in a comfortable setting so that it doesn’t influence the emotional state indirectly. Try to keep the room temperature at a comfortable level. If the patient is feeling too cold or too hot, adjust the temperature accordingly. Let the patient becomes comfortable in that setting before taking a reading.

Uncalibrated Reading Device

The sphygmomanometer or digital blood pressure monitor must be calibrated periodically. They must be serviced at least every six months [3]. Along with calibration, the bladder, cuffs, and tubes must be properly checked for damages periodically. This will help you to get accurate readings every time.

Improper Cuffing

This is a very common problem that can give you unstable readings. It is important to choose the correct cuff size according to the arm size of the patient. You need to have cuffs for adults and kids separately. Also, cuffing on top of clothes can give you improper readings. Therefore, you need to properly cuff the patients [3].

Blood Pressure Reading

Having a full bladder

Studies have shown that taking a reading after relieving the bladder can differ up to 10mmHg [4]. So, it is better to ask the patient to urinate and get relieved completely before a reading. Also, the stress to relieve the bladder can increase blood pressure and alter the readings. Therefore, a full urinary bladder can highly influence the readings.


Certain medications can influence blood pressure levels in the body. Sympathomimetic drugs [1] can highly influence your blood pressure and it is not recommended to take them on the day of a medical checkup. The doctor must ask for the patient’s medical history and make sure there aren’t any drugs that may affect the blood pressure.

Involving in physical activity

Before reading, it is not advised for the patient to walk or involve in physical activity. Intense physical activities like running will also increase blood pressure and show inaccurate readings. Therefore, you must make sure to keep the patient at rest before taking a reading. If the patient has walked to the clinic, let them be at rest for at least 15 minutes.


Studies have shown that there is a 10mmHg difference in the systolic pressure when the patient is listening to the doctor’s talk [5]. Therefore, it is a must to be quiet and observe the pulse while taking the reading. When the patient is actively listening, it can affect their blood pressure significantly.

Unsupported Arm

Sometimes the patient’s arm is not properly supported and this can produce abnormal readings. Studies have shown that an unsupported arm can produce a 5-11mmHg difference in readings [6]. Therefore, you must always support the arm of the patient in a suitable manner and make them comfortable to get accurate readings.


This is one of the influential factors that can give an irregular blood pressure reading. Patients who have smoked half an hour before reading has produced a 6-20mmHg difference in the systolic pressure readings [4]. Therefore, advise your patients to quit smoking or at least avoid smoking before taking a reading. This will help them to get a better reading.

Apart from these major factors, you can also have significant changes in readings if you consume caffeinated drinks. Therefore, it is recommended to avoid coffee and similar drinks.


The importance of blood pressure readings is not unknown to anyone. You can easily diagnose a person with hypertension or other diseases because of a false abnormal reading. Therefore, it is very crucial to be cautious with all the influential factors that can affect the readings. We have listed all the important factors you might find in your daily life which may give you an improper reading. If you avoid these, you will be able to diagnose the condition correctly.


  1. Accurate, reproducible measurement of blood pressure
  2. Recommendations for Human Blood Pressure Determination by Sphygmomanometers
  3. Recommendations on blood pressure measurement
  4. The Importance of Accurate Blood Pressure Measurement
  5. The effects of talking, reading, and silence on the “white coat” phenomenon in hypertensive patients
  6. Does This Patient Have Hypertension?