What is a common symptom of exposure to carbon monoxide?

A common symptom of exposure to carbon monoxide is a headache. Carbon monoxide is a colorless, odorless gas that can interfere with the body's ability to transport oxygen by binding to hemoglobin in the blood. When carbon monoxide enters the bloodstream, it can lead to insufficient oxygen delivery to the brain and other organs, causing a range of symptoms. A headache is often one of the first signs of carbon monoxide poisoning, as it can result from reduced oxygen levels or direct effects on the brain.

In contrast, while increased heart rate can occur due to various conditions, it is not the most direct or specific symptom of carbon monoxide exposure. Itching skin typically does not relate to carbon monoxide poisoning and is more associated with allergic reactions or irritants. Extreme fatigue may occur in more severe cases or longer-term exposure, but it is generally a less immediate symptom compared to the headache that often arises quickly after exposure. Thus, in the context of initial awareness and common symptoms, a headache stands out as a hallmark indication of carbon monoxide exposure.