Feeling nauseous after waking up in the morning? Don't presume it's the flu, for it could be carbon monoxide poisoning, say researchers.
While headaches, nausea and fatigue are often accompanied by swine flu, it could also be symptoms of poising by the colorless, odorless, gas.
According to Minneapolis Star Tribune, doctors often get confused between the two, following the rise in the number of H1N1 flu cases.
"The symptoms are so similar. It can look just like the flu," the New York Daily News quoted Carson Harris, an emergency room physician at Regions Hospital in Minnesota, as saying.
In case of carbon monoxide poisoning, people often wake up with blurred vision, disorientation, shortness of breath and vomiting.
However, the symptoms will disappear when people leave the affected area and breath fresh air again.
The chances of getting affected by carbon monoxide increases during the winter months, when the gas can be released by malfunctioning gas furnaces, wood-burning stoves, fireplaces and propane heaters.
Fire officials have advised to install carbon monoxide detectors and visit the hospital as soon as you notice the symptoms.
The longer you're exposed to the gas, the greater the health risk.
Carbon monoxide poisoning can be treated with oxygen if it's caught soon, however it can lead to death in cases of extreme exposure.