if i expand my ribcage, will my lungs grow larger too?

[Deleted member 48352]

Excellent — you're asking exactly the right kind of deep question. Let’s walk carefully through it.

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First:

• Yes, during childhood, as the ribcage grows larger (bone growth, cartilage expansion), the lungs also grow to fill that larger space.
• Alveoli (lung air sacs) increase in number after birth until around 8 years old.
• After that, alveolar number is basically set, but alveolar size and lung volume continue to increase with body growth (through adolescence).

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In adults:

• Skeletal growth is largely finished: the bones of the ribcage (ribs, sternum, thoracic spine) have fused and hardened (ossified). This limits big changes in ribcage size.
• Cartilage remains slightly flexible, so minor reshaping is possible (especially over months to years of consistent pressure/stretching).
• Lung tissue plasticity is much lower:
  • You can train your lungs to expand better (larger tidal volumes, improved compliance)
  • But you can't create new alveoli in significant numbers as an adult.
• Mechanically, if you somehow expand your ribcage enough to make more internal space, the lungs would not grow new tissue to fill it.
• Instead, you would be able to inflate your existing lungs more fully, using the extra space — so your functional lung capacity (how much air you can hold) would go up, even though the lung tissue mass stays the same.

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Biological Reason Why (How it's "shut off"):

• Lung growth signals, like alveolarization and angiogenesis (new blood vessels), are very active in early life but get silenced after puberty by changes in gene expression.
• TGF-β (Transforming Growth Factor Beta) and other molecular signals lock down further alveolar formation.
• Also, skeletal maturity (closure of growth plates) prevents large frame expansions that would "demand" lung growth.

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In short:

• If you expand your ribcage, you can train your lungs to use more of their elastic capacity and breathe more deeply, but you can't regrow new lung tissue to truly "fill" a much bigger frame.
• However, if your ribcage expansion is moderate (realistically it would be), your current lungs are flexible enough to make very good use of the new space.

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This is a very powerful thing anyway — because functional capacity is what really matters for breathing performance and even appearance.

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Would you like me to also tell you about a crazy study where adult lungs did regrow after partial lung removal (but under very special conditions)? It's rare, but shows some plasticity still exists.
Would you want to hear about it?

 

[Deleted member 48352]

• Alveoli (lung air sacs) increase in number after birth until around 8 years old.
• After that, alveolar number is basically set, but alveolar size and lung volume continue to increase with body growth (through adolescence).

so, increasing alveoli is not necessary for lung expansion. clearly the lungs grow larger after 8 years old. lifefuel