Ever wonder why the rats in your house always are scurrying around in the middle of the night, but nowhere to be found when you wake up? Well it is because they have a different chronotype make up than humans. Chronotypes measure the internal clock, or sleep patterns, of animals and humans. Scientists often use the Morning-Eveningness Scale to assess the chronotypes a person possesses.

Scientists have studied chronotypes to better understand what triggers sleep cycles and if they can be altered. Unfortunately, for college students and other demanding lifestyles, a person’s chronotype cannot be altered. Although everyone has different chronotypes, humans are divided into two main groups: “Larks” and “Owls.”

But, it is important to remember that the average circadian clock for humans does not drastically vary.

In an experiment published in Biological Rhythm Research called Associations of waking EEG structure with chronotype and trototype of 130 sleep deprived individuals, they attempted to influence the sleep-wake cycle of individuals and see how chronotypes were affected. They used a controlled experiment that aimed to measure what variables sleep deprivation affected. As mentioned earlier, there is no replacement for sleep, but everyone has different sleep needs.

 Chronotypes- Morning Larks and Night Owls

http://www.sleepdex.org/chronotypes.htm

Associations of waking EEG structure with chronotype and trototype of 130 sleep deprived individuals

http://dx.doi.org/10.1080/09291010903018057