The study interviewed more than 170,000 people about their health and sleep behaviors and matched them up with death records years later. The researchers considered five sleep factors in their measure of quality sleep. The first was whether or not people got the ideal amount of sleep, which was seven to eight hours. The next two factors considered how hard it was for people to fall asleep and sleep through the night. The fourth factor asked if people took sleep medication, and the fifth was about how rested people felt upon waking up.
For people to score the full five points for sleep quality, they would have to get at least seven hours of sleep, fall asleep easily and stay asleep at least five nights a week, take no sleep medication, and wake up feeling rested five days a week. People who scored five points on sleep quality had a longer life expectancy than those who had one or zero of the sleep factors.
Sleep quality also factored into the risk of dying from certain conditions. Those who scored five points had a 30% lower risk of all-cause mortality, 21% reduced risk of cardiovascular death, and 19% lower risk of cancer death. One cautionary note about the study was that the people reported their own sleep habits, so there wasn’t an objective means to verify their sleep patterns.
