Know Your Reading: Guide to Use a Blood Pressure Chart/Machine

“You’re raising my blood pressure”, said every Indian mother to her child. Well, if the pressure is high, let’s measure it. After all, an accurate blood pressure reading will tell you what to do next. Measuring blood pressure used to be quite a task.

Back in the day, blood pressure was measured primarily using the auscultatory methods, which involved using a sphygmomanometer (inflatable cuff) and a stethoscope to pick up the sounds of blood flowing through the arteries.

Historically, mercury-based sphygmomanometers were standard. However, today, we have aneroid and electronic devices due to concerns surrounding mercury toxicity. The earliest documented measurement of blood pressure involved inserting a tube into the artery of a horse to observe the rise and fall of blood pressure.

Well, we’ve come a long way since then. Today, there are a litany of blood pressure charts/machines so you can get an accurate reading and decide what to do next. Today, blood pressure is typically recorded as two numbers:

Systolic Pressure (the top number): This is when your heart beats and pumps blood.

Diastolic Pressure (the bottom number): The pressure when your heart is at rest between beats.

The steps for using a blood pressure chart/machine are given below.

You will need -

1. A high-quality stethoscope

2. An appropriately sized blood pressure cuff.

3. A blood pressure measurement instrument, like an aneroid or mercury column sphygmomanometer, or an automatic device having a manual inflate mode.

Enter the patient. Ensure the patient is relaxed by giving them 5 minutes to relax before the first reading. The patient must sit upright with their upper arm positioned so it is level with their heart and their feet flat on the floor.

Get rid of excessive clothing that might impact the BP cuff or constrict blood flow in the arm. And yes, make sure you and the patient are completely silent during the reading.

Pick the right BP cuff size. Most measurement anomalies occur when the proper cuff size is not chosen. Wrap the cuff around the patient’s arm, and use the INDEX line to determine whether the patient’s arm circumference falls within the RANGE area.

Or pick the appropriate smaller or larger cuff.

Palpate/locate the brachial artery and place the BP cuff so the ARTERY marker points to the brachial artery. Wrap this BP cuff snugly around the arm.

On the same arm that the BP cuff is placed, palpate the arm at the antecubical fossa (crease of the arm to find the strongest pulse sounds and place the stethoscope’s bell over the brachial artery at this location.

It's time for action. Start pumping the cuff bulb as you check for pulse sounds. When the BP cuff has inflated sufficiently to stop the blood flow, you should hear no sounds through the stethoscope.

The gauge must read 30 to 40 mmHg over the person’s regular BP reading. If said value is unknown, you could inflate the cuff to 160-180 mmHg. (If pulse sounds are heard, inflate to a higher pressure.)

Start deflation. According to the American Heart Association, pressure should fall at 2-3 mmHg per second; anything faster could most likely cause an inaccurate measurement.

As blood starts to flow through the artery, the first rhythmic sound heard is the patient's systolic pressure, which might initially resemble a tapping noise.

Carry on listening as the BP cuff pressure drops and the sounds fade. When the rhythmic sounds cease, note the gauge reading—thisis the diastolic reading.

Take a ride with both arms and average them. Wait five minutes between readings to check the pressure again for accuracy. Blood pressure is usually higher in the mornings and lower in the evenings.

If the blood pressure reading is a concern or hypertension is suspected, you might need to study the patient’s blood pressure for 24 hours to get an overall blood pressure profile.

Different blood pressure readings mean different things. Given below are a few instances of what each reading means.

Normal Blood Pressure

Systolic: Less than 120 mmHg

Diastolic: Less than 80 mmHg

Healthy range. Keep up good lifestyle habits!

Elevated Blood Pressure

Systolic 120–129 mmHg

Diastolic: Less than 80 mmHg

Not yet high blood pressure, but it could become it. Time to adopt healthier habits.

High Blood Pressure (Hypertension) Stage 1

Systolic: 130–139 mmHg

Diastolic: 80–89 mmHg

Lifestyle changes are important. Medication may be recommended depending on risk factors.

High Blood Pressure (Hypertension) Stage 2

Systolic: 140 mmHg or higher

Diastolic: 90 mmHg or higher

Likely requires both lifestyle changes and medication.

Hypertensive Crisis (Emergency care needed)

Systolic: Higher than 180 mmHg

Diastolic: Higher than 120 mmHg

Seek immediate medical attention, especially if symptoms like chest pain, shortness of breath, or vision changes occur.

Understanding how to accurately measure and interpret blood pressure is one of the most empowering things you can do for your physical health. Whether you are a healthcare provider, caregiver, or just looking after yourself or a loved one, using the correct technique and knowing what the numbers mean is important.

Blood pressure monitoring has come a long way, and today, it’s easier than ever to be informed and proactive. So the next time your mom tells you you’re raising her blood pressure, hand her a cuff, measure it correctly and take charge - because knowledge is the first step to control.

Can I measure my blood pressure at home without a stethoscope?

Yes, you can! Digital blood pressure monitors are designed for home use and do not require a stethoscope. They’re user-friendly and provide systolic and diastolic readings with the push of a button.

What time of day is best for checking blood pressure?

Blood pressure is usually higher in the morning and lower in the evening. For consistency, measure it at the same time each day, ideally after resting for a few minutes.

How often should I check my blood pressure?

If you're monitoring for medical reasons, follow your doctor’s advice. Otherwise, once or twice a week is enough for general tracking—just make sure you're calm and rested during each reading.

Does cuff size really matter when checking BP?

Absolutely! Using the wrong cuff size can lead to inaccurate readings. Too small = falsely high readings; too large = falsely low. Always match the cuff size to your arm circumference.

What should I do if my BP readings vary a lot?

Blood pressure can fluctuate due to stress, activity, or even posture. If you're seeing frequent or large variations, track it over several days and consult your doctor to rule out any underlying issues.