The average person falls asleep within seven minutes and stays asleep for eight hours. Those who have no difficulty sleeping often take this interrupted shut-eye for granted. Those who suffer from insomnia struggle for every hour of sleep that they get.
Insomnia is a sleep disorder that affects approximately 15pc of the Irish population and, according to experts, it's on the rise.
In an international survey carried out by Aviva health insurance last year, 35pc of Irish adults said they do not believe they are getting the right amount of sleep. The same survey ranked Ireland as the second most sleep-deprived country after the UK.
Another recent survey commissioned by Ikea, and designed by paediatric sleep consultant, Lucy Wolfe, found that one-third of Irish people are getting less than six hours sleep a night.
RTÉ meteorologist Joanna Donnelly recently opened up about her battle with the sleep disorder in an episode of Claire Byrne Live.
"Insomnia is a debilitating condition that can go on for days and leave you just out," she said. "I can't eat, I can't exercise, I can't think straight."
Donnelly has suffered from insomnia for 30 years, but she still has to "paint on the face, and put on the smile" for her front-of-camera job.
ITV newsreader Tom Bradby can probably relate. The anchorman has been off sick from work with "crippling insomnia" for seven weeks at the time of writing.
Insomnia is defined as difficulty falling asleep or staying asleep, even when a person has the chance to do so. It affects more women than men and more older people than younger people. And it's strongly linked to stress, anxiety and depression.
Most adults need between seven and nine hours sleep per night. However, individual needs vary significantly and it isn't just about quantity; it's about quality too. A person could get 10 hours of shut-eye a night, but if they are waking frequently, it's unlikely that they are completing the five stages required for restorative sleep.
Psychologist Karolina Jurasik of MyMind says insomnia is a "civilisation disease" that is connected to the stress of demanding lifestyles. "Social media is another factor," she says. "It causes people to feel like they always have something to do."
Our increasing reliance on technology makes it harder for us to switch off at night, she adds. "Very often, people relax in front of their TV, phone or tablet but the blue light that these devices emit stimulate the brain too much at bedtime."
It's easy to forget that our circadian rhythm, or internal sleep clock, is linked to the light-dark cycle of the solar day. Light encourages wakefulness; dark encourages sleepiness. Or at least it should.
"The light bulb was a great boon when it was invented, but now it has been overused," says Dublin-based sleep technologist Motty Varghese. "There is no natural light-dark cycle any more. It has to be internally dark, even when the sun has set, for us to build up enough sleepiness," he explains. "But when we use electronic devices, we are tricking ourselves that it is not time to sleep."
Membership of the so-called '3am club' is widening but not all insomnia is created equal. The disorder can be transient, episodic or persistent. Some insomniacs find it hard to get to sleep while others wake up several times during the night.
Insomnia tends to be multifactorial, which is why sleep experts often cite the '3Ps' model - 'predisposing', 'precipitating' and 'perpetuating' - to explain how it progresses.
If a person is predisposed to anxiety, for example, it won't necessarily cause insomnia, but it will increase the likelihood of them developing it.
The precipitating factors are generally life stressors- workplace stress, relationship issues or even jet lag - while the perpetuating factors are the behaviours or habits that exacerbate the problem, whether it's bringing the iPad to bed or sleeping in at the weekend.
Symptoms include fatigue and low energy, difficulty concentrating and irritability. In more extreme cases, chronic insomnia can lead to paranoia and hallucinations. And just as anxiety and depression can be predisposing factors for insomnia; insomnia can be a predisposing factor for anxiety and depression.
"You think that you are worthless and paranoid, and 'nobody likes me'," said Donnelly during her interview. "It feels like it's real but it's not real, it's a symptom of your condition."
"A lot of people will go through phases of sleeping difficulty - two, three, four weeks - but they then identify what the problem is and they can correct it," explains GP Dr Jennifer Grant.
Chronic insomnia, on the other hand, occurs at least three times a week for three months or more.
"I don't believe in sleeping tablets," continues Dr Grant. "I'm happy to prescribe someone a month's supply, but I don't want anyone taking long-term medication that's not necessary."
The problem, she says, is that patients will often self-medicate by procuring sleeping tablets online or "doctor shopping".
"A person doesn't have to stay with the same GP," she explains. "They can book into a clinic down the road and get another month's supply."
A study commissioned as part of the RTÉ documentary Awake found that 18pc of Irish adults have used sleeping tablets to get to sleep. Dr Grant says many of these troubled sleepers might benefit from specialist help.
But first a GP will try to identify any underlying conditions. Early morning awakening is a classic symptom of mild depression so, in this case, a doctor would explore the patient's other drives, such as motivation, appetite and libido.
In other cases, they may just need to manage expectations. "As we get older, our sleep deteriorates," says Dr Grant. "After the age of 65, we are only expected to get five to six hours of straight sleep, but sometimes people have unrealistic expectations."
If Dr Grant thinks a person needs to take time off work to deal with insomnia, she will generally give the patient a medical certificate citing 'respiratory tract infection'. "Generally people don't want their employer to know that they have insomnia or mental health related stuff," she says.
As this point the patient will be referred to a sleep technologist or a therapist specialising in CBT-I (Cognitive Behavioural Therapy for insomnia).
Motty Varghese asks patients to keep a week-long sleep diary before they come to their first session. This allows him to see how much time they spend awake before they turn the lights off; how long they take to fall asleep and for how long they are sleeping.
He'll talk to them about sleep drive, which he compares to appetite and thirst. Is the patient jeopardising his drive to sleep with lie-ins or afternoon naps in the same way that a snacker spoils his appetite for dinner?
Next, he talks about sleep habits. Is their bedtime and wake up time consistent? Are they bringing devices - smartphones, tablets, laptops and yes, even Kindles, into the bedroom? Is the bedroom "as dark, quiet and cool as a cave"? How much caffeine and alcohol are they consuming during the day?
Sometimes a few simple lifestyle changes can restore satisfying slumber. However, in most cases, Varghese will introduce CBT-I. "People maintain a lot of dysfunctional beliefs and attitudes about sleep," he explains. "And one of the most common dysfunctional attitudes about sleep is this idea of, 'If I don't sleep tonight I won't be able to function tomorrow'."
Varghese gives his patients coping statements and catastrophising strategies to use in this scenario. He reminds them that they've been able to raise a family and perform at work in spite of their insomnia. "Yes, they are tired and they feel terrible, but nothing major happened."
Jurasik takes a similar tack, but she also addresses the other worries that might be keeping the person awake.
"A lot of people would mention that they are worried about family or work," she explains. "Then they would lay in bed for hours engaging with those thoughts."
The conviction that one has insomnia - or what sleep researcher, Kenneth Lichstein, calls 'insomnia identity', doesn't help matters. It often leads to anticipatory anxiety and a fear of not falling asleep.
"The worry and anxiety that we attribute to the loss of sleep is not deserved," says Varghese. "So we help the person bring their anxiety level down, which in turn should enable them to sleep better.
"At the end of the day, we have to accept that we have no control over it," he adds. "You cannot bring sleep to you so there is no point trying to get to sleep. You have to be mindful and present. You have to accept it.
Sleep will happen - if you let it happen."
SLEEP BY NUMBERS
* Most adults need an average of seven to nine hours sleep each night.
* Humans spend an average of 25 years sleeping, or one-third of their life.
* 56pc of Irish people who have trouble sleeping are kept awake with a racing mind.
* 60pc of Irish people use their smartphone before bed.
* 27pc of Irish adults have used alcohol in the past month to help them sleep.
* 30pc of Irish people would like to sleep better.