A group of scientists from the Universities of Florida, Harvard, Emory, and the Mississippi Medical Center found that, contrary to popular belief, coffee does not cause insomnia. But cigarettes and alcohol do it.
The study, which lasted 14 years, was attended by 785 people, some of whom were African-Americans. Representatives of this race more often than others suffer from insomnia, sleep apnea and other similar disorders. It should be added that among the project participants there were no people with clinical sleep disorders.
Each subject received a sensor that was worn on the wrist and recorded all stages of a person’s sleep. At the same time, 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 virtually no effect on the subjects’ sleep. This conclusion has not changed even after taking into account their age, gender, weight and employment.
Insomnia more often overtook people who took alcohol – most often when a person consumed it before bedtime.
But the strongest factor causing sleep disturbances was smoking or vaping of nicotine-containing mixtures. Those who received a dose of nicotine in the evening slept on average 43 minutes less than non-smokers.