Considering a New Year’s resolution to quit smoking? New research might provide all the motivation you need: Each cigarette could shorten your life by up to 22 minutes, researchers say.

The findings, published Dec. 29, 2024, in the journal Addiction, were based on mortality data from British smokers and suggest that smoking a pack of 20 cigarettes a day can cost someone nearly seven hours of life.

“The time they’re losing is time that they could be spending with their loved ones in fairly good health,” said Dr. Sarah Jackson, lead author and principal research fellow at University College London’s Alcohol and Tobacco Research Group.

The research shows that smoking tends to erode healthy middle years of life, rather than just the later years often spent in poorer health.

The research, which was commissioned by the UK Department for Health and Social Care, includes mortality data on men from the British Doctors Study and data on women from the Million Women Study, a news release says.

The studies found that lifelong smokers lost an average of 10 years of life compared with nonsmokers.

“In terms of regaining this life lost, it’s complicated,” Jackson said.

“These studies have shown that people who quit at a very young age -- so by their 20s or early 30s -- tend to have a similar life expectancy to people who have never smoked. But as you get older, you progressively lose a little bit more that you then can’t regain by quitting. No matter how old you are when you quit, you will always have a longer life expectancy than if you had continued to smoke,” Jackson added.

For example, a person smoking 10 cigarettes daily who quits on January 1 could prevent losing a full day of life by January 8, a week by February 20, and a full month by August 5. By the end of the year, they could have avoided losing 50 days of life expectancy.

“Stopping smoking is, without a doubt, the best thing you can do for your health,” Jackson added.

Smoking rates have declined since the 1960s, but it remains the leading cause of preventable death in the U.S., killing more than 480,000 Americans each year, according to the U.S. Centers for Disease Control and Prevention (CDC).

In addition to its impact on life expectancy, smoking harms the immune system. A 2024 study published in the journal Nature found that smoking weakens the immune response and increases vulnerability to infections, cancers, and autoimmune diseases.

“The good news is, it does begin to reset,” Dr. Darragh Duffy, co-author of the Nature study and head of Translational Immunology at the Institut Pasteur explained about what happens when smokers decide to quit. “The best time to stop is now.”