Carbon monoxide poisoning: What it does to your brain, heart, and lungs

On Friday, atleast 90 people were killed in a coal mine blast in northern China. While the cause of the gas explosion has not been revealed yet, but media reports citing state media have said that the levels of carbon monoxide in the mine were found to have "exceeded limits".


In December 2024, 12 people died from carbon monoxide poisoning in Gudauri, Georgia at an Indian restaurant where workers were staying. It was a generator running in a closed room trying to heat the building during a power outage. The workers got nauseous and couldn't escape. Within hours, they were dead.






Carbon monoxide poisoning claims several lives every year. And most people have no idea how fast it actually works or why it's so dangerous.

Your blood stops carrying oxygen

Here's what actually happens when you breathe carbon monoxide. According to Harvard Health, carbon monoxide passes from your lungs into your bloodstream where it attaches to the hemoglobin molecules that normally carry oxygen. Oxygen can't travel on a hemoglobin molecule that already has carbon monoxide attached to it.


As you keep breathing the gas, more and more of your hemoglobin gets taken over. Your blood gradually loses its ability to carry enough oxygen to meet your body's needs. Your entire system starts suffocating from the inside. Without enough oxygen, individual cells suffocate and die, especially in vital organs such as the brain and heart. Carbon monoxide also acts directly as a poison, interfering with cells' internal chemical reactions. It's not just about oxygen deprivation. CO is actively poisoning you at the cellular level.

The brain gets hit hardest

Your brain is the most sensitive organ to carbon monoxide because it uses more oxygen than almost anything else in your body. When poisoning starts, you might get confused. You can't think straight. Your personality changes. Then serious brain damage sets in. The CDC warns that the effects are caused not only by impaired oxygen delivery but also by disrupting oxygen utilization and respiration at the cellular level, particularly in high-oxygen demand organs like the heart and brain. Severe cases cause cerebral ischemia and hypoxia. Brain cells actually die. And sometimes that damage is permanent. People who survive severe poisoning often have neurological complications—memory problems, difficulty concentrating, personality changes.

Your heart starts struggling

Your heart is working overtime trying to pump blood through a system that's being starved of oxygen. It can develop irregular rhythms. You might feel chest pain. In serious cases, the cardiac injury is so bad it increases mortality risk for the next 10 years after poisoning. According to the CDC, cardiac injury during poisoning increases risk of mortality within 10 years following poisoning. People survive the initial poisoning but their hearts never fully recover.

Your lungs can't do their job

The CDC lists the most common symptoms of CO poisoning: headache, dizziness, weakness, nausea, vomiting, chest pain, and altered mental status. Difficulty breathing is often one of the first warnings your body gives. But by the time you notice you can't breathe properly, it's usually too late to escape. The poisoning works fast. At high concentrations, death can come in minutes.


Carbon monoxide is completely undetectable. You can't see it, smell it, or taste it. It just silently accumulates in your blood while you feel increasingly confused and sick. And once it's in your system, it takes about a full day for your body to eliminate it.