Breathing
Breathing is a stat: The ability of a character to breathe. Improving this stat increases movement speed. Its default value is 100%.
Breathing is impaired by damaged lungs. A character missing a lung has breathing reduced by 50% but can still survive. Without lungs, all breathing ceases and the organism will die. Lungs can be harvested and transplanted from other humans.
Breathing bears a small weight in the movement stat, hence why Asthmatics will be slightly slower than healthy colonists.