What Are Circadian Rhythm Sleep Disorders?

Life has changed.

Life used to be simpler. Just a few decades ago, we would get up and wind down with the sun. And we spent much more time outdoors than we do now. This was important for our health, because we each have an internal body clock that depends on sunlight to tell us when to be active and energetic, and when to sleep.

Now with our hectic lifestyles, we often miss these critical signals from the sun, and our body clocks suffer. Without proper morning light, our body clocks don't produce the hormones we need to wake up and feel active. When we miss daytime light, we slump and become less productive. At night, we usually stay up hours after dark, causing sleep and mood problems. In fact, how we sleep, how active we are and how we feel are all regulated by our body clock.

What are Circadian Rhythms?

The signals our body clock produces are called circadian rhythms (sir-kadian). Circadian is Latin for 'about a day', and it describes the changing levels of hormones and neurochemicals that control our sleep, activity and mood. When our body clock misses critical zeitgebers (body signals) such as bright morning light or evening darkness, its rhythm may shift, and as a result, your body will produce hormones at the wrong time, or stop producing the right amounts. When your sleep or mood suffers, you may likely have a circadian rhythm problem. Medical journals report that most mood and sleep disorders have an underlying circadian rhythm disorder.

Circadian Rhythm Epidemic

Because of our hectic lifestyles, we don't get the zeitgebers nature intended, and as a result, circadian related disorders are reaching epidemic proportions. For example, studies show that we only average 21 minutes of effective sunlight a day, far less than just a few decades ago. This may be one reason why the rate of depression and related disorders has doubled over the last 50 years, and sleep disorders have tripled during the same time.

This epidemic intensifies in the fall and winter when we lose even more sunlight. Most sleep and depression sufferers report worse problems in winter, and The National Institutes of Health (NIH) estimates that 6% of Americans suffer from a depression known as Seasonal Affective Disorder (SAD), while another 14% have a milder form, called Winter Blues. Almost 18% of Americans suffer from depression and anxiety. In the US, over 65 million people suffer from circadian related disorders.

Next: The Circadian Pathway »