High blood pressure is diagnosed when blood pressure readings are consistently higher than the normal level.
However, the readings are affected by when the measurements are taken.
According to the Mayo Clinic, blood pressure is highest in the mid-afternoon and lowest during the night.
“Blood pressure has a daily pattern,” the America-based clinic wrote online.
“Your blood pressure starts to rise a few hours before you wake up, and continues to rise during the day. It usually peaks in the middle of the afternoon before starting to drop again.”
High blood pressure: Does BP change during the day? When is it highest?
Guidelines produced for the NHS state blood pressure should be measured twice a day, “ideally in the morning and evening”, before a diagnosis of high blood pressure can be made.
“The recording should continue for at least four days, ideally for seven,” continued the National Institute for Clinical Excellence (NICE).
“For each blood pressure recording, two consecutive measurements should be taken, at least one minute apart and with the person seated.”
This will detect whether a person’s blood pressure fits the pattern for high blood pressure, or if they have a separate condition.
“Having an abnormal pattern, such as high blood pressure during the night or early in the morning, can mean you have a health problem,” said the Mayo Clinic.
High blood pressure: This can be highest around the mid-afternoon and lowest during the night
High blood pressure: This can be highest during the mid-afternoon
Individuals are more at risk of developing high blood pressure if they are overweight, don’t exercise regularly, or drink lots of alcohol.
The Mayo Clinic added working the night shift, smoking, and anxiety could all cause an “abnormal blood pressure pattern”.
“Taking blood pressure medications that don’t last 24 hours”, can also have an effect.
“Your doctor can tell you if an abnormal daily blood pressure pattern may need treatment,” the Clinic continued.
“He or she may recommend a 24-hour blood pressure monitoring test.”
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Hot weather and drinking coffee shortly before a test can also impact the blood pressure reading.
The Mayo Clinic says you should test your blood pressure 30 minutes after drinking a beverage containing caffeine, to find out whether it had an effect.
“Caffeine can cause a short, but dramatic increase in your blood pressure, even if you don’t have high blood pressure,” said the Mayo Clinic online.
Being in hot weather for long periods of time, however, can actually lower blood pressure, they added.
Sheldon Sheps, a former member of the Clinic’s Department of Medicine said, “blood pressure is generally higher in the winter and lower in the summer”.