...And breathe

We do it upwards of 22,000 times a day, but we could still breathe better – and it might just make us better cyclists

- JAMES SPENDER

Why do we breathe? 

Simply put, we breathe to exchange gases. Oxygen – specifically molecular oxygen, O2 – is key to the production of adenosine triphosphate (ATP) in cells, the energy-carrying molecule responsible for delivering chemical energy to fuel everything from cell division to nervous system signalling to muscle contraction. ATP is the reason you can grow muscles, command chains of kinetic movement and, ultimately, power a bicycle.

However, ATP production creates a byproduct – carbon dioxide, or CO2 – which must be expunged, since while CO2 is not toxic to humans per se, it is an asphyxiant, meaning it leaves no room for oxygen molecules. Breathing, and hence our respiratory system, is the key to getting oxygen in and carbon dioxide out.

How does breathing work? 

Oxygen enters the body via the lungs, diffuses into the bloodstream via the lung’s air sacs, the alveoli, then attaches to red bloods cells, or haemoglobin (Hb). This oxygen-rich blood is then transported to cells around the body to produce ATP. The CO2 produced off the back of this process must then be removed from cells to free up room for more oxygen molecules, so the whole system works in reverse: CO2 molecules bind to haemoglobin so they can be transported to the alveoli, diffused into the lungs, and exhaled.

Data published in the journal Breathe describes how breathing increases from around 15 times per minute at rest to ‘40-60 times per minute during heavy exercise’. The upshot of all this is a body of thought that breathing can be optimised to increase physical performance.