What is a common physiological result of chronic lung disease?

Thickened blood can be a common physiological result of chronic lung disease due to a variety of factors, including chronic hypoxia and the resulting polycythemia vera, where the body compensates for lower oxygen levels by producing more red blood cells. This increase in red blood cells can lead to an elevated hematocrit and hemoglobin level, causing the blood to become more viscous or "thick." This adaptation, while an attempt to improve oxygen transport, can contribute to complications such as increased blood pressure and the risk of clot formation.

In contrast, other options do not typically result from chronic lung disease. For example, chronic lung disease often leads to reduced oxygen levels rather than increased blood oxygen levels. Weight loss can occur due to the increased work of breathing and other metabolic demands, but it is not a direct physiological result like blood thickening. Reduced blood pressure is generally not associated with chronic lung disease, as chronic conditions often result in other cardiovascular changes rather than hypotension. Thus, thickened blood is a direct consequence of the body's efforts to counteract the effects of decreased oxygen availability in chronic lung disease.