The initial symptoms of carbon monoxide poisoning are similar to the flu. They can include dizziness, severe headaches, nausea, sleepiness, fatigue/weakness and disorientation/confusion. Symptoms vary depending on exposure:
Common Mild Exposure - Slight headache, nausea, vomiting, fatigue, flu-like symptoms.
Common Medium Exposure - Throbbing headache, drowsiness, confusion, fast heart rate.
Common Extreme Exposure - Convulsions, unconsciousness, brain damage, heart and lung failure, followed by death.
If you experience even mild carbon monoxide poisoning symptoms, you should immediately consult a physician!