Beats Per Minute and Blood Pressure

What are beats per minute and blood pressure?

Beats per minute, otherwise known as BPM, is a measure of how fast the heart beats over a given period of time. This is sometimes called ‘heart rate’. On average, a human heart beats between sixty and a hundred times a minute – this varies from species to species.

Blood pressure, on the other hand, is how hard the heart beats every time it beats. It is measured by checking the pressure with which the blood pushes against the artery walls.¹ Blood pressure is measured in mmHg (millimetres of mercury, which is a unit of pressure). Normal blood pressure is 120/80 mmHg. The two numbers correspond to different things:¹

• The top number measures the systolic pressure, which is the pressure in the arteries when the heart beats
• The bottom number measures diastolic pressure, which is the pressure in the arteries when the heart relaxes

In short, the main difference between BPM and blood pressure is that BPM is how many times the heart beats in a minute, whereas blood pressure is how hard it beats when blood is being pushed around the body.

Does high blood pressure increase heart rate?

Blood pressure and heart rate do not necessarily increase together or at the same rate.² There may be times when both rise and fall together, whilst, at other times, one may increase whilst the other decreases.

When exercising, for example, both heart rate and blood pressure increase. This is because there is an increased need for oxygen and energy, so the heart beats harder and faster to make sure that the body gets this.

However, if someone were bleeding heavily, their blood pressure would decrease, but they would have a high heart rate. This would be because there would be less blood, but the heart would still be trying to supply the body with oxygen and energy.

Does heart rate affect blood pressure?

Again, the relationship between blood pressure and heart rate is not perfectly aligned – depending on the situation, blood pressure and heart rate will respond differently.

It has been suggested that a higher heart rate may be associated with an increased risk of high blood pressure. This, however, appears to be dependent on location in body.³ Centrally, that is around the major organs (the heart, lungs, liver, kidneys and brain), the relationship between blood pressure and heart rate is inverse – this means, as one rises, the other drops.

Peripherally, that is in the limbs (both arms and legs), the relationship appears more direct, meaning as one increases, so does the other.

It is important to note that they may not increase at the same rate, for example, an increase of 30 BPM may not translate to an increase of 30 mmHg, as blood pressure usually rises more slowly.

How can you measure your heart rate?

Heart rate can be measured in a number of ways. The easiest for most people is to set a timer for thirty seconds and count how many times their heart beats in that time. This number can then be multiplied by two.

You may feel your heartbeat by placing two fingers on a pulse point; this may be the neck or wrist. This method, however, maybe a little inaccurate. The aim is for your heart rate to be between sixty to a hundred at rest. After exercise or other physical activity, this may increase. 

Everybody is different but you can calculate your maximum heart rate very easily: by taking away your age from 220. This is the maximum number of times your heart should beat in a minute when you are exercising. Maximum heart rate decreases as you get older (for a twenty-year-old, it would be 200, but for an eighty-year-old, it would be 160).

Target heart rate is a range of heart rate values that you should aim for during physical activity. The values change depending on the intensity of the exercise you are doing:⁴

• When doing moderate exercise, your target heart rate is between sixty-four and seventy-six per cent of your maximum heart rate
• When doing vigorous exercise, your target heart rate is between seventy-seven and ninety-three per cent of your maximum heart rate

What is the normal blood pressure level?

As mentioned before, normal blood pressure usually sits at around 120/80 mmHg (this is read as ‘120 over 80’). However, everybody is different. Some people’s blood pressure may naturally sit higher or lower than this depending on your body; somebody who is larger and more muscular may have a higher blood pressure than somebody who is smaller and has less muscle.

For this reason, there is more of a shift towards an acceptable range of blood pressure. Between 90/60 mmHg and 120/80, mmHg is generally accepted as being ideal.

High blood pressure is 140/90 mmHg or above. If a doctor sees these readings regularly, at different points in time, they may diagnose a person with high blood pressure and prescribe them anti-hypertensives (which are drugs used to bring blood pressure under control) and advise them to make lifestyle changes.

People with pre-high blood pressure, and even high blood pressure to a certain extent, may not even realise they have it, as it is generally asymptomatic (does not produce symptoms).

If blood pressure reaches 180/120 mmHg or over, with symptoms such as chest pain, shortness of breath or changes in vision,⁵ this is known as a hypertensive crisis and can be life-threatening. This would therefore be a medical emergency. A reading of 180/120 mmHg without other symptoms is known as hypertensive urgency.⁵

Low blood pressure is anything less than 90/60 mmHg. Low blood pressure is usually accompanied by symptoms such as feeling dizzy or faint.

Exercise and diet to maintain normal levels

Diet and exercise are important to maintaining normal blood pressure and heart rates.

The heart is a muscle, and therefore, like with all muscles, training it will make it stronger. Just like working out your arms will grow your arm muscles and allow you to lift heavier things, working out your heart will enable it to work more efficiently and pump with more power, decreasing the number of times it has to beat in a minute. Furthermore, if your heart is strong, you can put it under more strain, and it will be able to cope.

Cardiovascular exercise (also known as cardio) is important to help maintain healthy heart rates.

Diet is important to maintaining normal blood pressure – having a diet that is high in salt and fat can increase blood pressure. This is because salt draws more water into the blood, meaning there is more blood, so higher pressure. Fats can cause narrowing of the blood vessels (atherosclerosis), which means blood has to move at a higher pressure in order to allow the affected area to get the right amount of oxygen and nutrients.

Summary

Heart rate is a measure of how many times your heart beats in a minute. Blood pressure is how hard the blood is pushing against the arteries. Both are important indicators of health and can be maintained through lifestyle choices, namely exercise and diet.