Cigarette smoke begins poisoning the body immediately, so that even occasional smoking can block one's arteries enough to trigger a heart attack, says the newest U.S. surgeon general's report.

"That one puff on that cigarette could be the one that causes your heart attack," U.S. Surgeon General Regina Benjamin said in a statement announcing the report.

It was a U.S. surgeon general's report in 1964 that first raised the alarm about the health dangers of smoking. There have been 30 reports on the dangers of smoking since, with this one devoting more than 700 pages to detail the biology of how cigarette smoke kills, both slowly and sometimes suddenly.

The report notes that more than 7,000 chemicals spread through the body with each cigarette puff, causing cellular damage in nearly every organ.

Cigarette smoke changes the chemistry of blood so that it becomes more sticky, allowing clots to form. In people who already have silent artery disease, even one cigarette can squeeze shut narrowed blood vessels, the report explains. And no one knows which cigarette it will be that leads to a stroke or heart attack.

"The chemicals in tobacco smoke reach your lungs quickly every time you inhale causing damage immediately," Benjamin said.

"Inhaling even the smallest amount of tobacco smoke can also damage your DNA, which can lead to cancer."

More than 1,000 people are killed every day by cigarettes. About one half of all long-term smokers will eventually die of a smoking-related disease, the report says.

On the other hand, kicking the habit allows the body to begin healing immediately, Benjamin said.

"It's never too late to quit, but the sooner you quit the better. Even if you're 70, 80 years old and you're a smoker, there's still benefit from quitting," she stressed.

The report also looks at latest genetic findings that help explain why some people become more addicted to the nicotine in tobacco than others, and why some smokers develop tobacco-caused disease faster than others.

The e dangers of secondhand smoke are also highlighted in the report. It cites as an example the town of Pueblo, Colo., which banned smoking in all public places in 2003. In just three years, the number of people hospitalized for heart disease plummeted 41 per cent.

The surgeon general said the report underscores the need to step up efforts to dissuade people from smoking in the United States, where 23 per cent of adults smoke and where there has been little change in the smoking rate since 2005.