A trio of new studies show that too little or too much sleep is associated with an increased risk for cardiovascular disease. Sleeping less than five hours per night raises the risk for a heart attack or stroke by about the same degree as smoking does, according one study in older men. This adds to a significant body of evidence that suggests regular sleep is essential for health.
Although individual needs may vary, sleep researchers generally say people should get seven to nine hours of shut-eye per night. That’s considered the amount that’s optimal for good cognitive performance, safety, and brain health, and for lower risk of cancer and death.
When it comes to cardiac disease, the authors of the meta-analysis found that the sweet spot for lowest risk was six to eight hours of sleep per night. Averaging less than that was associated with an 11% increased risk for dying from coronary heart disease or stroke at some point in the follow-up period of approximately 9.3 years, and getting more than that was associated with a 33% increase in risk.
Another study on sleep, conducted by a different team of scientists, was also presented at the European Society of Cardiology conference. Those researchers had people wear a waist-band monitor for one week to track their sleep patterns. The results suggested that people who got less than six hours of sleep per night or woke up frequently had about 27% more atherosclerosis: hardening in the arteries that can lead to blockage or narrowing and contribute to heart failure, stroke, or aneurysm.
Yet another new study presented at the cardiology conference reported on a group of 798 men from Gothenburg, Sweden, who provided information on how long they slept in a 1993 survey, when all participants were 50 years old. Twenty years later, the men who had said they slept less than five hours per night were found to have double the risk of a serious cardiovascular event. That increased risk for a heart attack or stroke is comparable to the effects of smoking or having diabetes.