I’ve known people who sleep only 4 or 5 hours a night and always seem fresh—like the saying goes, they “wake up like a lettuce.”
But how true is it that sleeping well actually makes us physically better? Is it real? Let’s take a look.

According to the World Health Organization (WHO), around 5.7% of adults worldwide suffer from depression. In absolute numbers, this represents approximately 280 to 332 million people across the globe. Additionally, it is more common in women than in men.

In the scientific field, various studies mention that both sleeping too much and sleeping too little are associated with an increased risk of death. However, a group of researchers at the Cleveland Clinic in Ohio, United States, discovered that the amount of sleep we get is directly related to quality of life and depression.

In this study, Charles Bae and his colleagues analyzed the records of 10,654 patients, whose average age was 52 years. Through a questionnaire, they evaluated quality of life and the presence of depression. They observed that patients with a normal sleep duration (between 6 and 9 hours) reported better quality of life and lower depression severity, compared with those who slept fewer than 6 hours or more than 9.

Reference:
Bae C, Jehi L, Novak E, Obuchowski N, Katzan I. “Effect of Total Sleep Time on Quality of Life and Depression” (Abstract #771). Presented at SLEEP 2011 (Meeting of the Associated Professional Sleep Societies), June 14, 2011.

The researchers concluded that “those who sleep too little or too much have a lower quality of life, as well as a greater tendency toward depression.”

Based on this, we can say that sleeping at least 6 hours and no more than 8 is a healthy average that contributes to better quality of life and reduces the risk of depression. But we must also add other habits: exercising, maintaining social circles, and practicing hobbies we enjoy—activities that together help us live better.

For example, the American Academy of Sleep Medicine (yes, it really exists) recommends that rest needs are individual, but most adults require between 7 and 8 hours of sleep to wake up alert and feel rested during the day.

So, how many hours do you sleep?