Heavy smokers are prone to what change in the red blood cell count?

Heavy smokers often experience secondary polycythemia due to chronic exposure to elevated levels of carbon monoxide in cigarette smoke. This gas binds to hemoglobin more effectively than oxygen, reducing the amount of oxygen available to tissues. In response to this low oxygen level (hypoxia), the body compensates by producing more red blood cells in an attempt to enhance oxygen delivery. This physiological response leads to an increase in the red blood cell count, which characterizes secondary polycythemia.

The other conditions listed, such as macrocytic anemia, hypochromic anemia, and microcytic anemia, are typically related to deficiencies in vitamins, minerals, or chronic diseases rather than the direct effects of smoking-induced hypoxia. Therefore, while it's important to understand various anemias, the significant change associated with heavy smoking primarily involves secondary polycythemia.