Sleep does not come easy, especially if you are in Cairo.
"I'm addicted to being awake," says Sameh Marghani, under the dizzying lights of a Cairo neighbourhood teeming with families shopping and teenagers nodding to the boom-boom of their car stereos.
It is midnight in Heliopolis, in northern Cairo, where the late night bumper-to-bumper traffic gives no hint of a workday beginning nine hours later.
"It's not in our culture to sleep early," says another night owl, Abdo, 39, who asked that his surname be withheld.
"The only reason to go to bed early is if you are going to get a pay cut for showing up late at work, otherwise, why sleep early?" asks the balding man with deep dimples, who admits his children regularly stay up until seven in the morning watching television.
"During the school year, I usually tell them to go to bed earlier... but in the summer, there is no reason to push them," Abdo says, implying that sleeping early is seen as a punishment.
Nicknamed the Big Mango -- after New York (the big Apple), the other city that never sleeps -- Cairo is home to some five million people who suffer from a sleeping disorder, a third of the population, according to international studies.
Ibrahim al-Sayyed has no option but to stay awake. He holds down a daytime job and sells balloons in the evening. He steals naps here and there whenever he can.
"I need the money," Ibrahim told AFP, holding a bouquet of brightly coloured balloons. "I usually end up sleeping about four hours a day."
Scientists say adults should ideally get eight hours of unfragmented sleep a night.
"I never sleep before one or two in the morning," says Sherifa Taher, a mother of two, who gets up at six every day to get her boys ready for school.
"By the time the boys get home from school, they relax a little, have dinner and then their private tutors arrive. They never finish before nine or 10... so my personal time begins at 10 pm."
Substandard schools have created a shadow education system whereby rich and poor parents alike are forced to arrange for private tutoring for their children after school to ensure a shot at passing national exams.
Sleep problems in megalopolis are fuelled in part by stress, unemployment and Cairo's infamous noise levels.
A new sleep clinic, the first of its kind in the country, has now opened in Cairo to try give Egyptians back their zzzs.
"Ninety percent of people who have sleep disorders don't know they have a problem," Ramez Reda Moustafa, a lecturer of neurology and psychiatry at Cairo's Ain Shams University told AFP.
Moustafa, also a visiting lecturer at Cambridge University, has been working for two years with his partners to set up the Sleep Care Clinic, which opened its doors two months ago.
The clinic is starting to draw more and more bleary-eyed clients.
In the waiting room, Hani Ramadan, a timid 30 year-old accountant in a suit and tie, is hoping Dr. Moustafa will put an end to his year-long sleep problems.
"I don't sleep at night. Sometimes I'd be at work and I really can't keep my eyes open," says Hani as a technician prepares him for a polysomnography, a sleep study which records breathing, snoring, and muscle activity during sleep.
Hani will spend the night in a specially created bedroom at the clinic that is not unlike an average hotel room or bedroom. He will be filmed throughout the night and doctors will monitor his sleep.
Sleep disorders treated at the clinic range from insomnia, the inability to initiate or maintain sleep, to snoring and sleep apnea, the periodic stoppage of breathing during sleep.
The UN World Health Organisation says in a study that "noise, stress and shift work can cause reduced sleep and fragmented sleep."
"The main effects of sleep deprivation include physical effects (sleepiness, fatigue, hypertension), cognitive impairment (such as) deterioration of performance, attention and motivation... and increase of the likelihood of accidents at work and during driving," the study says.
"There are many reasons why Egyptians have a hard time sleeping," says Dr. Moustafa. In addition to the factors mentioned by WHO, "we are big tea drinkers, a large part of the population is overweight; all these reasons are not conducive to a good night's sleep."
Treatment will depend on the condition.
Once respiratory, heart-related and neurological problems are dismissed, patients may be advised to alter lifestyles by cutting back on caffeine and taking up exercise.
They may be given sleeping aids, such as a little contraption clipped on the nose to help reduce snoring or they may need medication.
Manal, a 21-year-old waitress at a Cairo cafe, has no illusions why sleep is such a problem in the Big Mango.
"It's not a gym-obsessed culture, and we cook very fatty food, and we like to stay up late," she says. "It doesn't sound very healthy, does it?"
Others have no reason to obey normal sleep patterns.
"If I have nowhere to go, why should I get up?" asks Shadi Mohammed, 24, who is unemployed. He graduated from a technical college four years ago and has since then been struggling to get full-time work. He gets by with odd jobs here and there.
He prefers staying up at night with his friends, having a shisha (waterpipe) at a local cafe. Going to bed early fills him with anxiety.
"It just means I get up earlier and have a whole day to remind me that I have nothing to do.