I am a pediatrician and sports medicine-trained physician, parent of two middle school athletes and supporter of youth activity and movement in order to maintain health.

Remembering that sports is a means of learning about life, society and yourself, I am always hopeful our communities can find ways for everyone to be active and engage in physical movement. This overall view of healthy living through sports leads me to believe we should start school later for our middle and high school students.

The American Academy of Pediatrics has recommended starting school no earlier than 8:30 a.m. for all middle and high school children. This is reinforced with similar endorsements by the American Academy of Child and Adolescent Psychiatry, American Thoracic Society and the Centers for Disease Control and Prevention.

We all know puberty is a time of great change physically and emotionally, but what many are not aware of is the simultaneous shift in our internal clock.

Teenagers of many animal species are programmed to go sleep later, but they still require more sleep — about nine hours per night. With the hectic schedules our society has created for teens, many of them cannot achieve this needed goal.

In 2010, one study found only 8 percent of high school students slept close to nine hours per night, while 33 percent were sleeping six hours or less. Very quickly, these children fall into a sleep-deprived state.

Many others will speak to the general effect of sleep deprivation on mood, behavior, academic performance and cognition. I will focus on athletics and how starting school later can help our young active teenagers, and possibly open the discussion on how to get all teenagers to become more active.

Regardless of their sport, athletes want to continuously improve their performance. More and more of our young athletes are training year-round for one sport, with many of them overlapping with other sports throughout the year. Top that off with work, academics and a social life, and there is not much time left for sleep.

But sleep is critical. In 2012, one study found teens sleeping at least eight hours per night had a 68 percent lower risk of being injured than those sleeping less than eight hours. This sleep deprivation correlates directly with athletes suffering overuse- and fatigue-related injuries (stress fractures, tendinopathies, myofascial pain).

Why is sleep important to an athlete? When we sleep, our bodies cycle through rapid-eye-movement and non-REM stages in order to allow memory repair and consolidation, rebalancing of hormones and recovery of tissue damage from normal use and injury, all of which are critical for normal growth, learning and health.

With sleep deprivation, our stress hormone (cortisol) is elevated, our restoration of glycogen (stored fuel) is decreased and the ability to metabolize glucose is diminished by 30 percent to 40 percent. This leads to less fuel for the brain, decreased immune function to fight off illness and a greater risk of obesity.

Living in this chronically fatigued state increases the athlete’s risk of injury and possibly evolves into overtraining syndrome, where the body just can’t physically perform to its capacity anymore.

Athletes develop new skills and abilities by pushing their bodies and minds beyond what they think they can do, let it recover and adapt to this new norm and then push it once again. This is how strength, endurance and accuracy improve.

Those with adequate sleep have been found to increase free-throw accuracy, faster sprint and reaction times and better mood. Those with inadequate sleep function with decreased focus, cognitive slowing, memory impairment, diminished attention and poor vigilance, all having a negative impact on performance.

It appears athletes can power through a single high-intensity test when tired, but without adequate sleep, they fatigue easily on submaximal, repeated efforts, which most sports require.

We all want to do what is right for our children. In this case, biology is telling us nine hours of sleep per night is what our teens need.

If I offered a medicine that would decrease the risk of injury, improve academic and sports performance, and allow maximal normal growth, with the side effects of a lower risk of obesity and improved mood in your teen — all for free — wouldn’t people knock down my door to get it? We have access to that medicine right now: adequate sleep for teens.

Shifting school start times likely will affect the timing of after-school activities. In regards to athletics, this can be done collaboratively among school districts and still allow the approximately 20 minutes required for pre-game warmups and completion of the game.

A healthier starting time at our middle and high schools will help the most important people in those schools: our teens.

Lucien R. Ouellette, M.D., a Saco-based pediatrician and sports medicine-trained physician, belongs to the Start School Later initiative.