You can force a kid to bed, but you can’t make him fall asleep. Especially if he — or she — is a teenager. It’s not adolescent rebellion. It’s adolescent metabolism.

They physically cannot fall asleep because their bodies’ internal clocks are on sort of a chronic daylight-saving time overdrive — which worsens through their teen years, ultimately tapering off in their 20s, according to Leigh Heithoff, clinical specialist with BryanLGH Medical Center West’s Department of Sleep Medicine.

The average adult body starts secreting the sleep-inducing hormone melatonin around 8 p.m. — about two hours before we become physically tired enough to fall asleep.

In adolescence (starting between ages 11 to13), there is a shift in the body’s circadian rhythms, causing teens to feel naturally more alert later at night and wake up later in the morning. From a biological standpoint, adolescents do not begin secreting melatonin until 9 or 10 p.m., which means they’re not tired until 11 p.m. or later.

In fact, 54 percent of high school seniors in the National Sleep Foundation’s 2006 Sleep in America Poll said they go to bed after 11 p.m. on school nights.  And because the average teen body needs nine hours and 15 minutes of sleep a night, that means they really are not physically or mentally ready to wake up until 8:15 a.m. or later, depending upon the time they fell asleep.

Yet, many teens need to be up by 6:30 or 7 a.m. for school, extra- curricular activities or jobs.

Add in other sleep-disturbing factors — late-night TV watching, IM-ing, Web surfing, late-day drinking of caffeinated drinks to stay awake, everyday stress, and a “restless legs syndrome,” in which the legs involuntarily move and disturb sleep —  and the average teen is about 12 hours short of sleep by the end of the school week.

So what? Can’t they make it up on weekends?

No, says Heithoff.

The human body can recoup only 12 hours of lost sleep. But cramming all that sleep makeup work into a weekend is counterintuitive, because the longer and later teens sleep in on a weekend, the more their circadian rhythm shifts and they get tired later and later as their body adjusts to that fluctuating sleep schedule, Heithoff said.

That’s why sleep consistency is so important — going to bed and waking up at the same time gives your body a rhythm to function on.

While there is a benefit to catching up sleep on weekends, Heithoff said teens should not sleep in more than one or two hours on a given day.

Key to all of this is the indisputable fact:

“Sleep is important,” Heithoff said. “It is a basic human need.”

And if you subscribe to the statement — “I’ll sleep when I’m dead” — you may just reach that goal earlier than others who regularly get the sleep they need.

While we are sleeping:

*  The body grows. Eighty percent of the body’s growth hormone is released.

“Sleep is when you grow. If you don’t sleep you won’t grow,” Heithoff said. “If you want to reach your maximum physical potential you need to get sleep.”

*  The body repairs itself — particularly its muscles and immune system.

*  Consolidates learning — improving short-term and long-term memory.

*  Improves stamina.

“Athletic performance is improved with increased sleep duration,” Heithoff said.

Sleep deprivation is much more than feeling tired, Heithoff said.

Lack of sleep:* Impairs brain function.

 

Brain-scan imaging shows how sleep deprivation impairs the brain’s frontal cortex — the part of the brain that allows us to plan, reason, make judgments, etc.

“If kids are in school before their brains are awake, they are not comprehending,” Heithoff said.

*  Alters personality. Lack of sleep makes us irritable, cranky, emotional, unable to focus. In some kids, it can actually make them hyperactive, leading to some misdiagnosis of Attention Deficit Hyperactivity Disorder.

*  Affects appetite. The body compensates for our tiredness by increasing ghrelin and lowering leptin production, which stimulates hunger. The hormones make our metabolism more efficient. In other words, it slows down the metabolism preventing us from burning off those extra calories.

*  Makes us prone to accidents and injuries.  We’re tired. We’re less alert. We’re clumsier.

“Drowsy driving is as dangerous as drunk driving,” states the National Sleep Foundation. “When you are sleep-deprived, you are as impaired as driving with a blood alcohol content of .08 percent, which is illegal for drivers in many states. Drowsy driving causes over 100,000 crashes each year.”

If we sleep as we should, one-third of our life should be spent sleeping, according to the National Sleep Foundation.

But in our society we treat sleep as a luxury, and our need for sleep as sort of a personality flaw.

The thinking is backwards, Heithoff said.

“We reason we have too much to get done, and we don’t have time to sleep. But the more we sleep the more we get done because our brains are ready to problem solve and cope with stress so much better,” she said.

And as with so many other healthful things in our children’s lives, the onus falls on parents to ensure their children get the sleep they need.

Parents need to give sleep the same importance they give to making sure their children eat the right foods, get the right amount of exercise and go to school, Heithoff said.

“Kids aren’t very effective at managing their own sleep schedule. They don’t recognize when they get tired, and so eventually they will fall asleep, but it is at the point where they are totally exhausted.

“And at that point they are in trouble. They will get fragmented sleep, have nightmares and night terrors, sleep walk …  Your job as a parent is to be able to predict their sleepiness and recognize the signs and symptoms of tiredness.”

Reach Erin Andersen at 473-7217 or eandersen@journalstar.com.