Spanish Federation of Sleep Medicine Societies

Taking melatonin supplements to treat insomnia for more than a year is associated with an increased risk of heart failure—including an increase in hospitalisations and mortality—within five years of use, according to a study presented at a conference of the American Heart Association. The study compared a group of 65,000 adults diagnosed with insomnia who had a prescription for melatonin with another group who did not have a prescription for this supplement.

Research published in the journal Hypertension has found an association between frequent naps and an increased risk of high blood pressure and stroke.