We all love sleep, right? It's the third pillar of health, after nutrition and exercise. But screens aren't helping.

Smartphones beep into the night, they shine an unhelpful blue light into our eyes before we try to nod off and they (thanks, Youtube) autoplay video after video.

Among the new wave of sleep activists is Perth school principal Dr Kate Hadwen. She has managed to persuade 600 students to surrender their phones before they go to bed.

Her trick was to hand out alarm clocks to every student who pledged to put their phone away at bedtime. "The response from parents and students has been amazing, overwhelmingly positive," she told Fairfax Media.

With a separate alarm clock, there's no excuse for a phone by their beds. Parents used the pledge as ammunition to argue the case at home. "We sold out K-Mart in Western Australia. We had to get them shipped in from other states."

With students about to return to school, other high school principals should follow Hawden's lead. Sleep is especially important but harder to get in prolonged summers that are uncomfortably hot.

Mobile technology is doing more than harming the kids, of course. Research shows that if children are exceeding screen time, then their parents and carers are as well.

"Switched on" and tethered as we are for work, smartphones have offered greater mobility and freedom but also delivered greater fragmentation of home life and more mental stress. A recent survey found a third of us make errors at work as a result of fatigue. A third of full-time workers say they are completely exhausted on a regular basis.

Teenagers who are on screens more than four hours a day are 3½ times likelier to sleep fewer than five hours a night, which is scary.

Another activist is Alex Soojung-Kim Pang, the founder of The Restful Company, based in Silicon Valley.

"Rest is the time we spend recovering. Today, we are neither working well nor resting well," he says. "We think that in order to do more, we've got to put in more hours, work more nights and weekends. That's backwards. We get more done when we ease up."

Drawing on neuroscience and psychology, Pang's research confirms that when we rest well, we are more creative and productive. And yet he says we live with a warped social norm that sees busyness as a status symbol.

As well as advocating more sleep, Pang promotes "active rest" (exercise and walking) and "deep play" (immersing ourselves in hobbies) in order to transform the way we work, create and think.

Sleep activism is attuned to the quality and pattern of sleep, not just the hours doing it.

Sleep has four stages and good sleep requires all four: light sleep, stable sleep, deep sleep and rapid eye movement (or REM) sleep. Deep sleep offers regeneration and emotional stability. REM is important for memory and dreaming and sometimes for problem-solving.

In the mid-1800s, the inventor of the sewing machine, Elias Howe, had the idea for it, but couldn't figure out exactly how it would work. In his dream, cannibals were preparing to cook him and were dancing around the fire waving their spears.

He noticed that at the head of each spear was a small hole, and that the spears were moving up and down. The idea of passing the thread through the needle close to the point, not at the other end, was the innovation that made his machine work.

Rest and study or work are partners; they don't take away from each other but sustain and improve each other. We need both.

Toni Hassan is a writer and an adjunct research fellow at Charles Sturt University's Australian centre for Christianity and culture in Canberra.