Smartphones, tablets and e-readers have made modern life the kind of speedy, all-access convenience Gene Roddenberry conceived of in his 1960s Star Trek program.

But health experts warn that the proliferation of these handy i-devices comes the flip side: impaired sleep for children and adults, and a possible connection between poor sleep and symptoms that are remarkably similar to attention-deficit hyperactivity disorder (A.D.H.D.)

“Blue light is the worst and that’s what is emanating from laptop computers and that is stimulating the super nucleus and decreases melatonin and you can not sleep,” said Dr. Shahriar Shahzeidi, assistant professor in clinical pediatrics at Holtz Children’s Hospital at the University of Miami/Jackson Memorial Medical Center, which conducts about 250 sleep studies a year.

The bright light from these devices tricks the brain into thinking it is still light outside and the production of melatonin, which aids sleep, occurs in the dark. Lack of sleep can cause an increase in hyperactivity and trouble focusing on tasks, maladies that mirror A.D.H.D.

Parents must set sleep routines and make sure their children are getting enough deep sleep. Also known as sleep hygiene, this is as important as brushing one’s teeth before bedtime. In other words, put the video games and light-emitting devices away at night an hour before bedtime.

“The teenage age is a whole ballgame by itself. Teens have lots of things to disturb sleep. Being very social, they don’t want to sleep because of texting and all these electronic things. Physiologically, they have delayed sleep phase syndrome — their sleep clock is set later. The problem in society is we have to be on time the next day and get prepared for going to school, which usually starts early in the morning. Because the majority of teens in the morning have lots of problems to wake up, during the day, between 2 and 4 p.m., they are extremely sleepy because their cortisol level drops,” Shahzeidi said.

That problem usually corrects itself by early adulthood, after age 20, he said.

Restful sleep, including the deep REM stage, is particularly important for children for proper growth and development. Several studies have found that children today have lost about an hour of sleep over the last few decades. At least 25 percent of U.S. children 5 and younger have some sort of sleep issue and 10 percent of all children are snoring.

“The problem is growing because of environmental factors, electronics. Kids have more obesity and have sleep disorder breathing,” said Dr. Juan C. Martinez, director of the Pediatric Sleep Center at Joe DiMaggio Children’s Hospital in Hollywood, which conducts about 350 pediatric sleep studies annually.

Martinez recounts a recent example.

“As I was talking with a mother, she was talking to me about Nintendo and how [her son] likes to play late into the night. The first thing that came out of his mouth was, ‘You’re not taking away my Nintendo!’ ’’

Other sleep problems in children include breathing disorders like sleep apnea and snoring, twitching limbs or restless leg syndrome.

“We do sleep studies for kids who have abnormal movements at night and are not clear on what they are,” said Dr. Marcel Deray, director of the Sleep Disorders Center at Miami Children’s Hospital, whose sleep lab does about 1,000 sleep studies, from birth to adult, annually. “For example, babies who have had an event of stopped breathing. When a baby stops breathing it can be acid reflux or seizures. These are two of the things we look at.”