One more scroll

It is midnight. You have an early start tomorrow, so you turn off the light and pick up your phone, planning to check one message. Forty minutes later, you are still scrolling through videos of strangers cooking, dancing or arguing. If this sounds familiar, you are far from alone. Surveys in many countries suggest that most young adults use their phones in bed, and many admit it keeps them awake longer than they intended.

Scientists point to two main reasons why late-night scrolling can harm sleep. The first is light. Screens give off blue light, which can delay the release of melatonin, the hormone that tells the body it is time to rest. The second, and probably more important, is the content itself. Social media is designed to hold our attention: every swipe might bring something new, and the brain responds to that uncertainty with a small burst of excitement.

Crucially, the problem is not only that we fall asleep later. Heated arguments in comment sections and endless comparisons with other people's lives can leave our minds racing long after the screen goes dark. As a consequence, sleep tends to become lighter and more broken, and we may wake up feeling tired even after a reasonable night in bed.

Not everyone agrees on how serious the problem is. Some researchers argue that the link between screens and poor sleep has been exaggerated, while others point out that people who already sleep badly may simply reach for their phones because they are awake anyway. Stress, caffeine and irregular working hours may matter just as much. That said, few experts would recommend taking a phone to bed.

Fortunately, small changes can go a long way. Leaving the phone to charge outside the bedroom is the simplest step, since it removes the temptation altogether. If that feels too extreme, a 'bedtime' mode, which silences notifications and turns the screen grey, can make the feed far less appealing. Replacing the last half hour of scrolling with a paper book or a podcast can also help the brain wind down.

None of this means we need to delete our accounts. However, it does mean treating sleep as something worth protecting. After all, no video is so good that it is worth feeling exhausted the next day.