A team of scientists from the Universities of Florida, Harvard, Emory and Mississippi Medical Center found that, contrary to popular belief, coffee does not cause insomnia. But it does cigarettes and alcohol.
The study, which lasted 14 years, involved 785 people, some of whom were African Americans. Members of this race are more likely than others to suffer from insomnia, sleep apnea, and other similar disorders. It should be added that there were no people with clinical sleep disorders among the project participants.
Each subject received a sensor that was worn on the wrist and recorded all stages of a person’s sleep. In parallel, the project participants kept a diary in which they noted how they slept, how they felt, what they ate, how much they smoked and drank.
Scientists were surprised to find that caffeine had almost no effect on the sleep of the subjects. This conclusion did not change even after adjusting for their age, gender, weight, and employment.
Insomnia was more likely to overtake people who took alcohol — most often when a person consumed it before bedtime.
But the strongest factor causing sleep disturbances was smoking or vaping nicotine-containing mixtures. Those who received a dose of nicotine in the evening, on average, slept 43 minutes less than non-smokers.