"Crying expands the lungs"

by Consuela Hendriks

We often hear people say that crying is good for babies, it expands and strengthens their lungs.


The truth is, it’s actually the other way around. Healthy lungs make a ‘good’ cry possible.


Lung volume and elasticity are related to how loud and long you can cry.

For example, Crying Vital Capacity (CVC) measures lung function in neonates. CVC is defined as the maximum volume of air expired in a single breath during a bout of crying. CVC is therefore a simple, accurate, non-invasive measurement that can detect abnormalities in clinically normal infants (Sutherland & Ratcliff, 1961).


Effects of crying


It ís evident though that crying causes increased heart rate and blood pressure, reduced oxygen level, elevated cerebral blood pressure, initiation of the stress response, depleted energy reserves and oxygen, interrupted mother-infant interaction, brain injury, and cardiac dysfunction (Ludington-Hoe, Cong, & Hashemi, 2002).


Neuroscience does not support or confirm the idea that crying is good for the lungs.


Not letting them cry it out isn’t bad for their lungs by the way, they won’t get lazy lungs or something like that…


Responsive care


Since there ís evidence to back up the idea that responsive parenting positively influences the developing brain combined with the evidence that dysregulation and the subsequent epigenetic changes as a result of separation (such as in a cry it out method) are actually harmful (Bergman, 2014), we prefer to choose the safe way.


Better safe than sorry.


You turned out just fine…


And then many of us have probably heard ‘I let you cry it out too and you turned out just fine’ right?’.


But is this really true?


Or did you already learn to suppress your emotions back then, after your emotional calls weren’t responded to…


Did you already toughen up back then and shield the world as your default out of pure survival strategy? Nothing or nobody can harm or hurt you…because being vulnerable was already out of the question back then?


Did it really not harm you or does it seem that way because you do not want to be a burden to anyone, keep everyone around you happy and satisfied, do you want to be ‘good’ and definitely not difficult?


The outcome doesn’t justify CIO


How undamaged or damaged you turned out says nothing about the justification of cry it out methods.


It says more about your resilience, your temperament, whether or not you were loved, nurtured and cared for, whether you are seen, whether you are allowed to be your true self and whether you are really heard.


We speak to adults who aren’t experiencing any adverse effects from an early cry it out experience.


We speak to adults where a cry it out experience still negatively affects their emotional and relational life on a daily basis.


We can imagine that there is a large group of adults out there that apparently doesn’t experience negative effects, but in whom a lot is suppressed and might come up later.


No proof of harm ≠ proof of no harm


There may not be any hard evidence that a cry it out method is harmful to a child.

But remember: no proof of harm isn’t the same as proof of no harm…


So again, better safe than sorry.


And just to be clear, we’re big fans of crying. Tears can reduce stress, give relieve and help accept things that cannot be changed in life, and a subject that we’ve written about before. But; only when crying can take place in a safe context.


So please, respond to your baby, cuddle them, reduce separation as much as possible, sing, rock, feed, provide physical and emotional proximity. You’re not spoiling them. The mother’s body is a baby’s natural habitat, supporting better outcomes both for normal healthy babies and for the smallest preterm infants (Bergman, 2014), not a cot in a room somewhere in your house.


It’s not hard work, it’s heart work.




Bergman, N. J. (2014). The neuroscience of birth-and the case for Zero Separation. Curationis, 37(2), 1-4.


Ludington-Hoe, S., Cong, X., & Hashemi, F. (2002). Infant crying: nature, physiologic consequences, and select interventions. Neonatal network, 21(2), 29-36.


Sutherland, J. M., & Ratcliff, J. W. (1961). Crying vital capacity: A simple and useful measure of a lung volume in the newborn infant with respiratory disease. American Journal of Diseases of Children, 101(1), 67-74.