A new study by University College London reveals that smoking a single cigarette reduces life expectancy by an average of 20 minutes, nearly double previous estimates of 11 minutes. For men, it’s a 17-minute loss, while women lose 22 minutes per cigarette.

Researchers emphasized the cumulative effects of smoking, noting that quitting sooner leads to a longer, healthier life. They stated that smoking primarily affects the relatively healthy middle years rather than shortening the later years often marked by chronic illness.

A 60-year-old smoker, for instance, may have the health profile of a 70-year-old non-smoker. With an estimated six million smokers in the UK (12% of the population), experts urge quitting as soon as possible to avoid what they call the “escalator of death.”