Understanding Circadian Rhythms

Circadian rhythms are defined as the physical, mental, and behavioral fluctuations that happen in our bodies over a 24-hour period, mainly in response to light and darkness. These rhythms affect our ability to sleep or be alert, and they help regulate things such as hormones, cell regeneration, and body temperature. Circadian rhythms are ultimately governed by our biological clocks.

Circadian rhythms do not just influence being awake during the day and asleep at night; they are also responsible for dips and rises of energy throughout the daylight hours. You’ve probably experienced the slump around 3pm—you’ve eaten lunch, used energy to tackle tasks early in the day, and then your alertness begins to decline. It is scientifically proven that the lowest points in our energy and alertness levels happen at two times throughout a 24-hour period: from 2am to 4am, and from 1pm to 3pm. Circadian rhythms can also play a role in whether you’re an early birds or a night owl. Studies show that, generally speaking, children are early birds. Then as they become teenagers and require more sleep, they become night owls. Later in life, people tend to shift back to being early birds and require less sleep to function at their same level.

Since circadian rhythms are so ingrained within our bodies, it can take several days to adjust to any disruptions. Jet lag is a prime example: when you travel into a different time zone, especially one that is several hours off of your normal routine, you can feel groggy throughout the day or have trouble sleeping at night. Your body will slowly adjust, and after a few days spent in the new time zone, you will have acclimated to a different pattern of sleep and wakefulness.

Shift work is another common cause of a circadian rhythm disorder. Working an overnight shift is contrary to the body’s desire to be awake when it is light outside and asleep when it’s dark, so people with this work schedule can have problems getting enough sleep and being alert at work. Likewise, someone who constantly switches between day and night shifts can have even more difficulty adjusting and keeping a high enough balance in his or her energy “bank.” Other factors such as pregnancy, certain medications, or diseases like Alzheimer’s and Parkinson’s can contribute to circadian rhythm disorders. Treating circadian rhythm disorders can sometimes require medication while in other cases, methods such as light therapy or behavioral techniques are used to correct the problem.