The human thorax changes depending on sex to meet oxygen requirements

The CENIEH publishes an article in the journal Scientific Reports showing that the capacity of the lungs and the size and shape of the thorax are larger in males than in females as they develop through adolescence and reach adulthood, which is due to diverging respiratory needs

 “Differences in development of the thorax, depending on sex, are very relevant at a time such as this, when a respiratory disease such as COVID-19 is having a huge impact on humanity. The fact that respiratory demand starts to statistically diverge from the age of 12 or 13, producing a greater need for oxygen in one sex over the other, may have a bearing on clinical treatment”.

Daniel Garcia Martínez, a paleoanthropologist at the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), highlights the relevance of the study on the development of the thoracic respiratory system from youth to old age in both sexes, being published today in the journal Scientific Reports.

The results of research into the shape, size and function of the thorax from aged 7 until old age, passing through puberty and adulthood, reveals that the demand for oxygen in males is considerably larger than in females, because they have a larger amount of lean mass (muscle, basically) in relation to height. This is reflected in pulmonary capacity, as well as in the size and shape of the thorax, which is wider in men than in woman as they go through adolescence and into adulthood.

Hormonal changes

We already know that development of the nasal part of the respiratory apparatus follows different trajectories depending on the sex, because male respiratory demand is larger than female, and this starts to show after puberty. This is related to a change in the proportion of lean mass, which is relatively higher in men than in women as they grow into adulthood. 

“Up until now we did not know whether these changes in the craniofacial respiratory apparatus are reflected in the thorax, where oxygen is processed and distributed around the body by the blood. This study now shows us that the shape, size and function of the thorax also change considerably, depending on the sex, when an individual reaches puberty. A series of hormonal changes take place in human beings at this age, meaning that energy demand in boys and in girls is different, as are the relative proportions of lean mass and fat mass”, reports Daniel García Martinez.