Do you wake up without help at daybreak, or would you sleep till late morning every day if you could? Most people tend to be either early risers, or “larks” while others are night owls, though many people tend to fall in between the two.
Research is telling us that these preferences are driven to a notable degree by genetic and biological differences. Different chronotypes are linked to genetic variations, and also by differences in lifestyle, mood disposition and cognitive function.
Scientists at Aachen University in Germany did brain scans of early risers, night owls, and “intermediate” chronotypes, who fell between the two ends of the spectrum. They found that night owls showed reduced integrity of white matter in some parts of the brain. White matter is tissue in the brain that enables communication among nerve cells. Decreased integrity of white matter in the brain has been linked to depression and interference of normal cognitive function.
Researchers speculate that diminished integrity of white matter may be due to chronic “social jet lag” that occurs in the sleep-wake routines of some night owls. For some of them, there is a constant battle between the schedule of life that encompasses them, especially around work and school schedules and the need to sleep later in the morning.
While studies indicate that night owls may run a higher risk of depression, as well as being inclined to having less healthful diets than larks and intermediate sleepers, there is also some good news for them. They tend to have more stamina throughout the length of their days, and may have greater analytical and reasoning abilities.
This new study offers for the first time physical evidence of neurological differences among people and their sleep tendencies.
Michael Breus, PhD, sleep specialist, and writer for the Huffington Post asks the question, “If our preferences for sleep and wake times are strongly influenced by genetics and biology, what are we to do when faced with inclinations that don’t match up with the demands and responsibilities of our lives?” He believes genetic forces play an important role in our preferences, but that should not make us feel powerless in how we live our lives. The choices we make about our sleep habits and sleep environments can make a difference. Limiting nighttime exposure to artificial light and increasing exposure to sunlight may help shift sleep-wake cycles earlier – even for night owls. Keeping the bedroom dark, and electronic-gadget free might also help.
Breus hopes that over time, we as a community acknowledge that we are wired differently. “I hope we’ll see society begin to recognize the power of these biological sleep patterns, and the need for flexibility to enable people to construct work and school schedules that align better with their dispositions toward sleep. This is a smart, sleep-friendly strategy that would be good for public health and productivity” says Breus. huffposthealth 12/1/13