Professional Opinion with Dr. Randall Evans, a pulmonologist on the staff at Hilton Head Hospital.
Q. “Like a lot of people, it has taken me more than a few days to get used to a new sleep schedule after Daylight Saving Time. Now I’m reading that an Oxford University researcher says that starting work before 10 a.m. is making employees ill, exhausted and stressed. Is there anything to this notion that working too early in the morning is not good for people and does it differ for children? And if so, what sort of sleep schedule is optimum for good health for both adults and children?”
A. There are two main systems that control our sleep/wake cycles.
There is an external system driven by external queues such as temperature and sunlight.
There is an internal system regulated by a compound adenosine. The longer we are awake, the greater the concentration of adenosine will be in our brains. It is this concentration that is responsible for “sleep pressure,” the term used to describe the urge to sleep. As we sleep, the adenosine is metabolized.
In a perfect world, we sleep through the night and, upon awakening in the morning, the adenosine has been completely metabolized, sunlight shines into our eyes and our brain knows it is time to wake up.
As the day progresses external queues tell us that the day is coming to an end and the adenosine once again accumulates in our brains. By night the adenosine is at its highest concentration and the outside world is telling our brains it is time to sleep. Understanding this, it is apparent that alterations to any of these systems will result in sleep cycle disruptions. This is why napping can be problematic. If you sleep for two hours during the day, adenosine has already been metabolized so by night you have less sleep pressure, making falling and staying asleep more difficult.
Similarly, changes in the clock (Daylight Savings Time) sets up a conflict between our internal clock and the new external clock. As a result, it often takes several days for the systems to realign.
Our internal clock is not static. As we age, our internal clock shifts. During adolescence, the internal clock is delayed, leading to the natural sleep period being pushed. This is why it is so easy for teenagers to stay up late but nearly impossible for them to get up early. As we age, our clock shifts forward. We are all familiar with our grandparents who go to bed by 7 p.m. and are up by 4 a.m. the next morning.
This has a major impact on children’s ability to stay focused in school. Numerous studies have proven that by delaying school start times, students perform better throughout the day.
Asking adolescents to start school at 7 a.m. is comparable to asking an adult to start work at 4 a.m.. They simply will be not able to perform their best.