even the first breath has to come out

When mammals are born the first breath is vitally important. The lungs have to be inflated in order to allow the use of oxygen and they contract to expel the carbon dioxide. Newborns need to start breathing soon in order to survive. The first breath is hard. A lot of force is needed. This reminds me of the force to inflate a new, flat balloon.

once they have started to breathe they cannot stop lest they will die.
Margaret Atwood : "Every breath you take is like the door stopper to keep death away"
The used carbon atoms in the exhaled CO2 are all around us and we add new ones with every breath.
AIR
a look at the anatomy of the lung


like the older balloon the lung can loose its elasticity (age, smoking) which is necessary to empty the CO2 outside >> the amount of fresh air that can be exchanged is decreased.
Breathing out is as important to breathing in ..... Let's enjoy every breath we take.