We're used to seeing toddlers who can't switch off at bedtime. But some experts think that our 'always on' lifestyles mean that many adults have the same problem
Nerina Ramlakhan remembers when her daughter was a toddler, and how if she got too tired she would be unable to switch off. "There was a healthy level of tiredness," she says. "But if she went beyond that, she would be running on a kind of false energy. And then she wouldn't be able to switch off when she went to bed."
Overtiredness is recognised the world over in young children - but it is seemingly more and more common in adults. Dr Ramlakhan should know: she is a sleep psychologist and is increasingly seeing people who remind her of her little girl when she was younger.
Overtiredness, sleep experts agree, is down to our always-on existence. In the past, says Ramlakhan, the author of The Little Book of Sleep, our days had naturally built-in downtime that gave us short snatches of rest. Today, that has disappeared for many of us.
專家認爲，過度勞累是由于我們總是保持清醒所致。《睡覺這件小事》（The Little Book of Sleep）一書的作者拉姆拉罕說道，過去，我們日出而作日落而息，但現在，很多人卻做不到這一點。
"We have become restless as a society - and that places more demands on us when we get into bed at night," she says. "We have lost the rituals and practices that gave us little respites during the day. In the past, you would go to the supermarket and, while you were waiting in the queue, you'd daydream, be a bit bored, look around. Now, any window like that will be filled by looking at your phone, answering some emails, sorting out your Amazon account."
You may think you are putting the time to good use - but that's not how your brain interprets it. There's a complex neurophysiology that requires breaks in tasks and concentration; if it's constantly bombarded, the brain becomes overloaded. The result, says Ramlakhan, is that it goes into what we might call survival mode: it assumes that something bad is about to happen, it ups the adrenaline and it puts out an urgent call for sugary snacks to provide quick-release energy.