Study: Smokers are sleep deprived

BALTIMORE, Feb. 4 (UPI) -- Cigarette smokers are four times as likely as non-smokers to report feeling unrested after a night's sleep, U.S. researchers found.

Study author Dr. Naresh M. Punjabi of Johns Hopkins University School of Medicine in Baltimore said smokers spend less time in deep sleep and more time in light sleep than non-smokers, with the greatest differences in sleep patterns seen in the early stages of sleep.

The researchers speculate nicotine's stimulating effect could cause smokers to experience nicotine withdrawal each night, which may contribute to disturbances in sleep.

"Smokers commonly experience difficulty falling asleep due to the stimulating effects of nicotine," Punjabi said in a statement. "As night evolves, withdrawal from nicotine may further contribute to sleep disturbance."

Punjabi and colleagues compared the sleep of 40 smokers with that experienced by 40 non-smokers. All of them underwent home polysomnography -- a recording of the biophysiological changes that occur during sleep.

The study, published in the journal Chest, found smokers had a lower percentage of delta power, or deep sleep, and a higher percentage of alpha power, or light sleep.