The smokers had not smoked for 24 hours

People who try to give up smoking may experience a slower sense of time passing, according to a study.

Researchers in the United States have found evidence to suggest that people who attempt to kick the habit lose their perception of time.

The phenomenon may be linked to the effects of nicotine withdrawal on the brain.

The researchers believe it may also contribute to the loss of concentration and increased levels of stress many people who try to quit experience.

Time tests

Dr Laura Cousino Klein and colleagues at Pennsylvania State University based their findings on a study of 42 men and women - 20 daily smokers and 22 non-smokers.

They asked all of the participants to estimate the duration of a 45 second period of time.

Nicotine leaves the blood within 48 hours so it should get much easier after just two days Spokeswoman, ASH

The smokers were asked to undergo the test twice. Once when they were smoking as normal and again when they had not had a cigarette for 24 hours.

The non-smokers and smokers recorded similar and generally accurate estimates after the first test.

However, the researchers found significant differences in smokers after the second test, when they had stopped smoking.

They all overestimated the duration of the 45-second period, suggesting that it had instead felt like more than one minute.

Dr Klein said this may explain why many smokers who try to quit become stressed and lose concentration.

"The time perception impairment that we observed in the abstaining smokers may be part of the reason they also reported feeling more stressed and unable to focus or be attentive," she said.

'No surprise'

The researchers said further study is needed to explain the phenomenon.

Writing in the journal Psychopharmacology Bulletin, the researchers said: "That 24-hour cigarette smoking abstinence can alter perceptions of time in a healthy, young, non-clinical population of smokers emphasises the need for future research to delineate the attention-altering effects of nicotine and nicotine withdrawal on addiction processes."

A spokeswoman for the UK charity Action for Smoking and Health said the findings were not surprising.

"We know that smokers do get agitated or stressed when they initially start nicotine withdrawal. It is not surprising that this also affects their perception of time."

But she added: "These sort of feelings are over very quickly. Nicotine leaves the blood within 48 hours so it should get much easier after just two days."