How Light Can Effect Our Sleep and Internal Clock

Did you know that light is the single biggest factor that affects our internal body clock especially when it comes to our sleep patterns. Each of us has a slightly different internal time, which can range from a 22 hour cycle (a fast body clock, associated with morning larks) to a 25 hour cycle (a slow body clock, which night owls would have). The average is around 24.5 hours.  

Sunlight helps us to adjust this internal time cycle each day to synchronize it with the world’s 24-hour cycle. It works like this: light hits the back of our eyes and travels into our brains, triggering the release of chemicals onto our body clock cells. This tweaks our internal time to be either slower or faster, making it exactly 24 hours. This also means that the more sunlight your eyes receive during the day can affect your clock by slowing it down or speeding it up when you don’t want it to. If you get lots of light in the morning, this will speed up your body clock and help you wake up earlier. Getting lots of light in the afternoon and around sunset will do the opposite—slow down your body clock and help you stay up later into the night. This is probably the best trick I know for helping your body to adjust to a new time zone after flying halfway around the world, so it’s great to understand how it really affects our bodies! Our dependence on light to keep our body clocks synchronized with the day’s 24 hour period is affected by our age, just like our sleep patterns are.

As we get older, two main things happen that relate to this: Our eyesight worsens, and we receive less light into our eyes Our body clock becomes less active Both of these things make our body clocks run slightly out of sync with the world. We start waking up a lot during the night, and often waking up far earlier than we’d like to. This is because the lack of light coming into our brains through our eyes gives a much weaker signal to our body clock cells to adjust them to a 24-hour period. And although we don’t lose any of our body clock cells, much fewer of them are actually active as we get older. What’s also important to consider here is that the importance of lighting in your office or at home is tightly connected to the temperature in your workplace too. Make sure that both are aligned to get an even better focus on your activities. There’s still hope, though. An experiment that tripled the amount of light dementia and alzheimer’s patients received during the day saw improvements in mood, better sleeping patterns, improved cognitive functions like memory and slower deteriorate of physical functions.