Did you know that there is a reason we feel awake and tired at the same time almost every day? These feelings are guided by our natural circadian rhythm. Let’s take a closer look at what this means and how it impacts our sleep.

Circadian Rhythm Defined

On the most basic level, circadian rhythm is our internal clock that runs 24/7 and cycles between periods of sleepiness and awakeness. The cycle happens over regular intervals and is also known as our natural “sleep/wake cycle.” Periods of feeling tired or awake can depend on the individual; adults usually have the lowest energy levels between 2 and 4 a.m. as well as 1 and 3 p.m.

A part of your brain called the hypothalamus primarily controls this rhythm, but other factors influence our natural sleep cycles. Sunlight and darkness are both signals for the hypothalamus to either feel awake or tired. When this signal occurs at nighttime our bodies release melatonin, making us feel tired. According to the national sleep foundation, “That’s why your circadian rhythm tends to coincide with the cycle of daytime and nighttime (and why it’s so hard for shift workers to sleep during the day and stay awake at night).”

Can You Change it?

Circadian rhythm is impacted by various factors, and we’ve all changed our sleep cycles without realizing it. When we travel to other time zones our bodies naturally adjust to our new location, but this isn’t the only way we change our sleep schedule. If you want to change things up it’s important to use light. If you want to change your circadian rhythm the National Sleep Foundation recommends “dim[ming] the lights in your home an hour before bedtime to prepare yourself for sleep.” When you wake up in the morning, turn multiple lights on to trigger the cut off of melatonin release in your brain.  


Good sleep habits can also lead to a better night’s rest and consistent sleep cycle. Keeping your body on a regular schedule can go a long way in boosting your mood and energy levels. Remember, circadian rhythms work best when you have regular sleep patterns.