How long do gas inhalation symptoms last?

How Long Do Gas Inhalation Symptoms Last?

Carbon monoxide (CO) poisoning is a silent threat—odorless, colorless, and potentially deadly. If you've been exposed, one of the most pressing questions is: how long do the symptoms last?

The answer varies, but generally, it can take up to 24 hours for CO to fully leave your body after exposure stops. During that time, symptoms like headaches, dizziness, nausea, and fatigue may persist as your system clears the toxin. However, for some people, the effects don’t end there.

Lingering symptoms—such as difficulty concentrating, memory problems, or ongoing fatigue—can last for days or even up to two weeks after exposure, especially in cases of moderate to severe poisoning. This is sometimes referred to as "delayed neurological sequelae," where the brain continues to recover even after the gas has been eliminated.

It’s important to seek medical attention immediately if you suspect CO exposure. Even if symptoms seem mild at first, they can worsen quickly. Early treatment with oxygen therapy can significantly reduce recovery time and prevent long-term complications.

Prevention is key. Installing CO detectors in your home, maintaining heating systems and appliances, and never running engines or generators indoors can help keep you safe. If you do experience exposure, don’t downplay the aftereffects—rest, monitor your symptoms, and follow up with a healthcare provider.

Recovery timelines vary from person to person, but understanding the risks and knowing what to expect can make a big difference in how you respond—and recover.