What happens when the lungs are unable to expel enough CO2?

When the lungs are unable to expel enough carbon dioxide (CO2), a condition known as hypercapnia can occur. This buildup of CO2 in the bloodstream leads to respiratory acidosis, where the blood becomes more acidic. The increase in acidity can affect various bodily functions, leading to symptoms such as fatigue and tiredness. This occurs because the body's metabolic processes become impaired, and the organs, particularly the brain, may not function optimally in an acidic environment. Consequently, the individual may experience a general sense of lethargy and reduced energy levels as their body struggles to manage the imbalance.

In healthy physiology, efficient gas exchange is crucial not only for maintaining normal oxygen levels but also for regulating CO2 levels. When CO2 is not effectively removed, it can lead to more severe complications, including confusion and decreased level of consciousness, which are also signs of fatigue commonly observed in patients with respiratory issues.