How do we breathe?
Our lungs are kind of like giant sponges. When you breathe
in, air is drawn down the windpipe or trachea, which splits
into two smaller tubes called the bronchi, and these carry
the air down into the lungs. The bronchi then split into
increasing numbers of smaller tubes called bronchioles, a
bit like the branches of a tree, finally reaching the tiny air
sacs called alveoli, of which there are some 300 million in
each lung! The walls of the alveoli are so thin that oxygen
can pass through them and enter the bloodstream for
distribution around the body. Similarly carbon dioxide,
a waste product of metabolism, can pass from the
bloodstream into the alveoli ready to be expired with the
next breath. The bronchial tubes secrete mucus to trap
dust, dirt and bacteria and stop them from entering the
lungs. Millions of tiny hairs called cilia then sweep back and
forth helping to shift the mucus away from the lungs and
keep them clean. Coughing also plays a vital role in this
process. Hence the recent advice in the media concerning
children and cough mixtures; paediatricians recommend
that these medicines are not given to children with a cough
as they should in fact be encouraged to cough to help
clear the infection. Similarly those with lung diseases such
as bronchitis or emphysema are encouraged to cough to
help clear their lungs, particularly first thing in the morning
when excess mucus and fluid may have settled in the lungs
overnight. It is important to learn how to cough effectively
– you ought to be able to clear your lungs in two or three
coughs. Your doctor or physiotherapist can teach you how
to do this.
So what are we doing wrong and how do you
breathe correctly?
At the bottom of the chest cavity is the diaphragm. It is a
dome shaped muscle largely responsible for moving air in
and out of the lungs. When we breathe in, the diaphragm
moves down allowing the lungs to fill with air, and when the
diaphragm moves up it helps to force air out of the lungs.
If you watch a baby breathing, their belly rises gently with
each breath in as the diaphragm contracts downwards,
and falls as they breathe out and the diaphragm moves
upwards. Yet somehow many of us as adults have
overridden the natural instinct to breathe in this way and
instead hold our bellies in (possibly because we are all
trying to look slimmer!) and breathe lifting our shoulders
with each breath. This “shallow breathing” is what correct
breathing techniques aim to rectify. There are numerous
versions of how to do it and these too have changed over
time. Many yoga techniques still teach a form of “belly
breathing” – in yoga they call it the “Complete Breath”
or “Dirgha Pranayama” – where the idea is to allow your
belly to expand with each inspired breath and contract
with each exhalation. This however is not quite correct
according to Bouvier. She says this common practice of
teaching leads to incorrect muscle use. Instead lie down
and place your hands on your ribcage. As you breathe in
you should feel your ribcage expand (think of widening
your ribs) allowing your lungs to fill completely, and on the
expiration pull your stomach in very softly, almost as if the
stomach deflates.
Then think about the speed of your breathing. Do you take
lots of shallow short breaths, or slow deep ones? Often
when we get anxious the muscles around the chest tighten
and we subconsciously start to breathe in a less effective
manner, failing to fill the lungs or fully expire “used” air.
When you do feel anxious or stressed take a few minutes to
stop and concentrate on your breathing. Try counting to
three as you breathe in, pausing for a moment, and again
counting to three as you breathe out. If possible, do this
breathing through your nose as this helps you to breathe
more slowly. The nose also plays an important role in filtering
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