An illustration from ‘The Breath of Life’ by George Catlin (1862).

Learn to breathe

We can do without food and water for a while, but we must keep breathing. How, then, can we investigate how breathing is controlled?

A stroke occurs when the blood supply to part of the brain is interrupted, causing brain cells to be damaged or die. The effects of stroke include paralysis and problems with sight, speech and memory. Strokes also sometimes disrupt different aspects of breath control and can help us to understand it better.

For example, the normal automatic control of breathing may be interrupted after a stroke, so that someone breathes normally while they are awake (and conscious of the need to breathe) but are likely to breathe shallowly, or even stop breathing, while asleep. This is sometimes known as ‘Ondine’s curse’, after a German folktale.

Breath control can be improved by special training, and devices that increase the load on the muscles involved in breathing may help speed recovery.

Some athletes now use inspiratory muscle training devices – which offer resistance to breathing for a short exercise period – to try to improve their performance. There are dangers when healthy people try and do a respiratory ‘workout’, though: breathing in and out more than usual reduces the amount of carbon dioxide in the blood.

If this goes too far, as in hyperventilation, it triggers a reduction in blood flow to the brain and can lead to dizziness or fainting. It also makes the blood alkaline, lowering levels of free calcium. This can lead to a tingling sensation and muscle spasms.

A note on breathing and respiration

It is important to remember that breathing and respiration are not the same thing. Breathing, or ventilation, covers the action of inspiration and expiration, or breathing in and out. Respiration is the name given to the cellular processes used to release energy from organic compounds. Click here to see our cellular respiration poster for more information.

Lead image:

An illustration from ‘The Breath of Life’ by George Catlin (1862).

Wellcome Library, London


About this resource

This resource was first published in ‘Exercise, Energy and Movement’ in January 2012 and reviewed and updated in August 2016.

Cell biology, Physiology, Health, infection and disease
Exercise, Energy and Movement
Education levels:
14–16, 16–19, Continuing professional development