The human body has many fascinating systems that run without us even being aware of them. One of the most important is the circadian rhythm. This is a 24-hour internal “clock” that governs the sleep/wake cycle. It is strongly influenced by light and is a vital aspect of human physical and mental health.
If you have ever experienced jet lag or seasonal affective disorder (SAD), you will understand what it feels like when your circadian rhythm is disrupted. You can’t seem to get a good night’s sleep, and during the day you might experience sluggishness, brain fog, and a general feeling of malaise.
Fortunately, jet lag goes away after a few days, and you start to feel better. This means that your “body clock” has readjusted to the current time zone, and your circadian rhythm is more or less aligned with the 24-hour day in whatever part of the world you happen to be.
You may not know it, but light plays a profound role in regulating the human body clock. The right type and intensity of light at the right time of day keeps the circadian rhythm properly aligned. The wrong type and intensity of light, on the other hand, can wreak havoc.
The fact of the matter is you don’t have to have actual jet lag to experience the symptoms of jet lag. Office workers who spend 90% of their time indoors often experience sluggishness and brain fog—not exactly because they aren’t spending enough time outside, but because they’re not getting the right light at the right time.
