According to the article, sleep is one of the strongest indicators of how long a person will live. Researchers analyzed national data and found that not getting enough sleep is linked to shorter life expectancy more than diet, exercise or loneliness. This link between short sleep and shortened lifespan has been shown consistently every year. This was true in most US states, suggesting that this is a widespread problem in the population. The recommended length of sleep in the article is seven to nine hours a day. This amount of sleep is presented as one of the simplest but very effective steps for long-term health.