Blood and is known as hypertension. Equations: Cardiac

Pressure (breathing rate and heart rate).

The piece
of equipment used to measure blood pressure is called a sphygmomanometer or
blood pressure monitor. These can be electronic or manual (aneroid). Aneroid
sphygmomanometers are said to be more accurate however they have to be used in
conjunction with a stethoscope to determine at which point blood is just
flowing and at which point its flow is unhindered. This makes them more
difficult to use.

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Theory behind the measurement of blood pressure.

The area for measuring blood pressure
is on the brachial artery. There are monitors that measure the pressure at the
fingers and wrists however people have found these to be unreliable. This is
because systolic and diastolic pressure varies greatly. In arteries far away
from the heart the diastolic pressure decreases and the systolic pressure
increases. The average blood pressure for humans is 120/80 mmHg. The systolic
pressure is when the heart contracts to pump blood round your body pushing on
the walls of your arteries this is the higher number of the two. This is
because the left ventricle pumps blood at high pressures during systole to
makes sure oxygenated blood gets all the way around the body. The pressure when
the heart is at rest between beats is called the diastolic pressure. This is
the lower number as the pressure in the walls of the arteries isn’t as high.

Systolic pressure of above 140 can
be bad for health as arteries and other vessels are constantly under stress-
this is called hypertension. Also, a diastolic pressure of above 90 is
considered to be high and is known as hypertension.


Cardiac output= heart rate x stroke

Stroke volume = amount of blood
pumped from the left ventricle in one contraction of the ventricle.

Factors that affect blood pressure (breathing rate and heart rate)

Age- as people get older the
efficiency of their lungs can decrease but not always.

Exercise- Heart rate increases
during exercise as more oxygen is needed around the body for respiration. Due
to this the breathing rate also increases to provide the extra oxygen required.

Drugs/Medication- Medicines can
cause a rise in blood pressure and heart rate. Some increase heart rate whilst
others decrease it.

Smoking- Smoking can cause an increase
in heart rate. Blood becomes less oxygenated due to carbon monoxide binding to
haemoglobin instead of oxygen. The carbon monoxide in cigarettes reduces
haemoglobin’s oxygen carrying capacity which leads to an increase in blood
pressure and also breathing rate in the long term. Also, the nicotine in
cigarettes contributes to an increase in heart rate.

Other factors include:

·    Being
overweight or obese

·    Lack of
physical activity

·    Too much
sodium in your diet

·    Stress

When and why would blood pressure be taken?

A person’s blood pressure may be
taken in order to find out if they have a high, low or normal blood pressure.

Hypertension- High blood pressure
that can put excess strain on arteries and organs, this can lead to more severe
problems such as heart attacks and strokes.

Hypotension-Low blood pressure
isn’t normally a worry however it can cause dizziness, fatigue and fainting.

The NHS says that all people over
the age of 40 should have their blood pressure tested every 5 years in order to
identify any health problems.

Blood pressure can also be measured
at home if you have the needed equipment.

If you have a blood pressure that
is abnormally high your doctor may recommend that you follow one of these:

·    Lowering
you salt consumption and eating a healthier, balanced diet.

·    Exercising

·    Stopping smoking.

·    Reducing
alcohol consumption.

·    Taking
medication such as Bumetanide (Bumex) and Ethacrynate (Edecrin).

·    If you may
are suspected to have a severe condition then you may be sent to a


A change in lifestyle and using medication can help to reduce
the risk of blood pressure and heart rate related complications. Regular
checking of blood pressure can help to detect any problems at an early stage.

Blood pressure chart with age









Heart rate chart


rate in BPM

Take a Deep Breath… Part I









Lung Capacity

The piece of equipment used to measure lung capacity is called a
spirometer. A spirometer measures inspiration and expiration. Inspiration is
the air breathed in and expiration is the air breathed out.





 – diagram


What does the
spirometer measure?

Spirometry measures the amount (volume) and/or speed (flow) of air that
can be inhaled and exhaled. The most common measurements used are:

Forced expiratory volume in one second (FEV1). This is the amount of air
you can blow out within one second. With normal lungs and airways you can
normally blow out most of the air from your lungs within one second.

Forced vital capacity (FVC). The total amount of air that you blow out
in one breath.

Last Checked 02 December 2016
Next Review 02 December 2019
Author Dr Colin Tidy
Peer reviewer Prof Cathy Jackson


Inspiratory capacity is the maximum
amount of air that can be breathed in.


IRV= Inspirational reserve volume

Maximum volume that can be inhaled
after a normal inhale.

Normal adult value 1900-3300 mL


ERV=Expiratory reserve volume

Maximum volume that can be exhaled
after a normal exhale.

Normal adult value 700-1200 mL


TV= Tidal volume

Volume of resting breath

Normal adult value 500 mL/breath


RV= Residual volume

Normal adult volume 1200mL


Dead space= Air inhaled during
breathing that stays in the conducting zone.

Normal adult value 150 mL


Total lung capacity= IRV+Vt+ERV+RV


Respiratory Capacities       


Normal adult values

Inspiratory Capacity (IC)


2400 – 3800 mL

Functional Residual Capacity


1800 – 2200 mL

Vital Capacity (VC)


3000 – 4600 mL

Total Lung Capacity (TLC)


4200 – 6000 mL

that affect lung capacity

Asthma can contract the airways and cause a person’s
lung capacity to decrease.

People at higher altitudes must breathe deeper because
there is less oxygen present in the air.








Measuring lung capacity can be used to determine any diseases
or health problems. Detecting and problems at an early stage is important so
people can get treatment if they have any issues with their lungs. It can also
help to detect inflamed, narrowed or obstructed airways. If you know you
already have a condition it can determine the severity of your condition.

Spirometry can be used to find out if you need an inhaler or
medications that can open up your airways. Reversibility tests are carried out.
These are where you use an inhaler or medication, wait for some time and then
repeat the test again to determine if they make a difference.

Think to the diagram and information used above.

Last medically reviewed:
January 2017. Due for review: January 2020


The diagram above shows the normal volume of air in a
person’s lungs and also the volume of a person’s lungs with restricted airflow.
The expiratory flow rate and volume of air is much lower. This could suggest
that the person has inflamed, constricted or narrowed airways or possible a
condition such as asthma.

There are a number of stretches and exercises that can be
done to increase lung capacity. Lung function can’t be improved however lung
capacity can here are a few methods;



Taking vitamins such as vitamin D which is thought to
increase respiratory muscle strength.

Avoiding dust and other airborne particles and
chemical fumes.

Do more cardio exercises to improve tolerance to





Peak Flow

Peak flow is the measurement of how fast someone can exhale.
It is measured using a peak flow meter.







To measure your peak flow you exhale into the tube. Make sure
the arrow on the side isn’t obstructed and take a reading on the side. Readings
for a peak flow meter can help to detect signs of asthma getting worse. A peak
flow meter can help to detect tightening airways sometime before an asthma
attack. This can help to detect and prevent asthma attacks. It can also help
people who don’t have asthma detect symptoms.

Calculation: Estimated
PEFR in Adult Females

(((Height x3.72) +2.24) – (Age x 0.03)) x 60
Where Height
in meters or (inches x 0.0254)

Calculation: Estimated
PEFR in Adult Males

(((Height x5.48) +1.58) – (Age x 0.041)) x 60
Where Height
in meters or (inches x 0.0254)














The graph above shows the average peak flow rate for men and women
at different heights. Peak flow values are not particularly useful for
detecting respiratory diseases however they can help to detect some diseases or
the severity of them.

Normal Peak Expiratory Flow (PEF)