Take sleep trackers, for instance. If you’ve got a smartwatch or fitness tracker, you can use it to gather information on the quality of your sleep.

“The existence of sleep trackers is fundamentally a good thing because they heighten awareness that sleep has a very important biological function,” says Dr Hans-Günter Weess, head of the Interdisciplinary Sleep Centre at the Palatinate Clinic for Psychiatry and Neurology, in Germany.

Sleep is the body’s most important regeneration and repair programme, he says, but then takes closer aim at sleep trackers.

“Most sleep trackers, sorry to say, are very imprecise. They measure neither sleep quality nor sleep duration accurately,” he says, adding that most have also not been scientifically tested.

The trackers are based on “Stone Age methods” of sleep research, he says, and often measure only the frequency of movement, time and user’s heart rate. Consequently, they can provide false results, and perhaps detect no sleep disorder when one is actually present.

There’s another drawback: people with a sleep disorder are particularly anxious about their sleep. Measuring it focuses them even more on their trouble sleeping – a vicious circle.

The more preoccupied you are with your insomnia, the more tense and restless you’ll be – and less likely to sleep well.

“Tension is the enemy of sleep,” Weess says. “People are able to sleep only when they’re not fretting about their everyday concerns and whether they’ll be able to sleep.”

He advises his patients to avoid the devices and rely on their own body awareness.

There are other technological sleep aids, such as metronome lights, that project a gently pulsating blue light onto the ceiling. If you synchronise your breathing with the light’s slow expansion and contraction, it will purportedly relax your mind and slow down both your breathing and heart rate.

White noise can have a calming effect too – that is, a monotonous sound experienced as pleasant, such as ocean waves or leaves rustling in the wind. There are stand-alone devices, apps and internet videos that produce white noise.

“Many of these digital sleep aids are meant to relax users and help them to better manage their mental, emotional or physical restlessness,” Weess says.

They’re rarely effective for people with a severe sleep disorder though, he points out, noting that only 1 to 2 per cent of his patients use white noise to help them sleep.

He cautions that the supposed effectiveness of most digital sleep aids isn’t backed by studies.

“They’ve got a hi-tech flair that gives the impression of scientificity,” he says, adding they can be quite expensive too.

Dr Thomas Penzel, scientific director of the Interdisciplinary Sleep Medicine Centre at Charité University Hospital in Berlin, affirms that very few digital sleep aids have been scientifically tested. An exception, he says, is Somnio, a digital health app for the treatment of sleep-onset and sleep maintenance insomnia.

Created by a German developer and distributor of digital medical products, it’s available on prescription in Germany. A study has shown that it can help remedy insomnia.

According to Penzel, the app mainly provides sleep hygiene rules – for example, maintain a regular bedtime and rise time, and keep your bedroom and workspace separate – in combination with consultation.

“Sleep isn’t something you can simply switch on – it’s a behaviour,” he says. “You’ve got to try to reduce stress and relax before you go to bed.”

Digital sleep aids can though be useful when part of a relaxing bedtime ritual, Penzel says. For some people the ritual is reading, for others a glass of warm milk, subdued lighting or white noise.

“Whatever calms you down is positive,” he says. “So you can’t say that all these gadgets are rubbish. If they’re used to bolster a [bedtime] ritual, then yes, they can help.”

Sleep coach Jan Herzog takes a similar view: “These tools don’t enable someone with a genuine sleep disorder to fall asleep quicker and sleep more soundly,” he says, although he does allow that in individual cases they can help a person to relax.

“In order for us to sleep, our nervous system has to switch from stress-and-performance mode to relaxation-and-rest mode,” he explains.

What truly helps to relieve insomnia, he says, is dealing with your worries and fears during the day so that they don’t keep you up at night.

“You should write down the three things currently causing you the most stress, and three ways to solve them. Then you won’t have to occupy your mind with them in the last 20 minutes of the day,” Herzog says.

In cases of severe sleep disorders, specialised cognitive behaviour therapy can help, Weess says.

“It’s always better when patients learn to be their own sleeping pill,” he says. “That means they learn how to enter a sleep-inducing state of relaxation and calm on their own, and not by taking a medication or using a technical aid.”