Checking your blood pressure at home can help identify potential health problems early, but one commonly overlooked step could make your reading appear much higher than it really is. Experts say emptying your bladder before taking a measurement could reduce an artificially raised reading by as much as 33mmHg.
According to the NHS, high blood pressure, also known as hypertension, often has no symptoms despite increasing the risk of serious conditions including heart attacks, strokes and kidney disease. Because it can go unnoticed for years, the health service recommends regular blood pressure checks, particularly for adults over the age of 40.
The specific advice to empty your bladder comes from the American Heart Association, which says a full bladder can increase systolic blood pressure by up to 33mmHg. That means someone whose normal top reading is around 120mmHg could temporarily record a reading closer to 153mmHg.
View 3 ImagesGoing to the toilet before is advised(Image: Getty Images)
Toby King, wellness expert and spokesperson for wellness company SoloFun, said many people are unaware that a full bladder can affect the accuracy of a blood pressure reading. He said: “This doesn’t mean that going to the toilet is a treatment for high blood pressure, but it does mean that someone close to a high reading may be in a healthier range than they thought, depending on the fullness of their bladder.”
The reason for the temporary increase is linked to the body’s nervous system. The American Heart Association claims a full bladder activates the sympathetic nervous system, which can temporarily raise blood pressure until it is emptied.
There are several other factors that can affect the accuracy of a blood pressure reading. Blood Pressure UK recommends sitting quietly for at least five minutes beforehand, keeping both feet flat on the floor, supporting your back and resting your arm at heart level throughout the test.
View 3 ImagesThis trick can reduce the reading by 33 points(Image: Getty Images)
It’s also important to avoid activities that can temporarily influence the result. You should avoid smoking, exercising or drinking caffeinated drinks for at least 30 minutes before measuring your blood pressure and avoid talking while the reading is being taken.
The advice is reflected in NICE guidance, which recommends taking blood pressure measurements in a standardised way to ensure they are as accurate as possible. NICE also advises taking more than one reading if the first result is unusually high before making any clinical decisions.
King said people should remember four simple steps before every home test: empty your bladder, rest for five minutes, sit correctly and remain silent during the reading. Following those steps can help ensure your reading is as accurate as possible.