Sleep Patterns

Human beings have adapted to living in a 24-hour environment by developing an internal timing system. The sleep-wake cycle is based on something known as circadian rhythms. The master clock of the body is known as the suprachiasmatic nucleus or SCN. This area of the brain governs the 24-hour cycle of sleep and wakefulness, and also maintains the circadian rhythm of other related variables of our body, such as our temperature and melatonin levels—all the things that let your body know when to sleep and when to wake. The strongest stimulus of this part of our brain is light. Exposure to light through the eye's retina at different times of the day either will advance or delay the circadian rhythm.

If you think you have insomnia, it is important for you to see your doctor. Be sure to discuss all of your symptoms, including whether you are experiencing fatigue, difficulty falling asleep, staying asleep, or early awakenings.

One of the best ways for your doctor to diagnose and provide treatment is if you keep a detailed history of your symptoms and sleep patterns in a sleep diary. This diary should be kept for at least one week and include weekends, and weekdays. A pattern of your sleep-wake cycle will emerge. In order to help better diagnose and treat your sleep problems your doctor may also suggest that you have additional tests that can be done at a sleep clinic.