Circadian Misalignment: External and Internal

Loss of optimal alignment of the Circadian Clocks and Circadian Rhythms they create alters sleep and performance, increases the risk of major disorders, from cancer to diabetes, impairs mood and accelerates aging .

External misalignment is between you and your environment: your Circadian Clocks tell one time, while the environment indicates a different time.

Internal misalignment is between You and You: your Circadian Rhythms lose their optimal mutual alignment, while you lose proper internal coordination of your body functions.

Causes of External Misalignment

The most common cause of external misalignment is a transmeridian flight, creating Jet Lag. This is followed by Shift Work involving either night shifts or significant day-to-day, or week-to-week change in work schedules. Stress and chronic disorders can also misalign your Rhythms, but are more likely to induce Internal Misalignment.

The so called "social jet lag", which happens when daily schedule is drastically different between the weekends  and work days, can also cause external misalignment.

Other types of misalignment with environment can reflect internal conditions, including blindness.

The Health consequences of Misalignment depend largely on whether an External Misalignment turns into an Internal Misalignment. 

How Internal Alignment can turn into Misalignment

Under normal conditions, all your Rhythms are following the Sun. They are synchronized with the 24-h light-dark cycle. They also follow a certain Optimal Alignment Pattern, defining who does what when. Some Rhythms, like sleep or melatonin production, peak at night. Other, like food intake or cognitive performance, peak during the day.

Having optimal alignment benefits each and all the Rhythms, and coordinates all your body functions the right way, to preserve health, sleep and performance.

Internal Misalignment happens when one or several Rhythms change their position in the Alignment Pattern.  They could remain synchronized with other Rhythms, keeping the same 24h Period, but their peak time is displaced. For instance, the peak of your Metabolic Rhythm might shift to the night period. As a result, you would not be that hungry during the day, but would wake up at night ready for a good meal. Those who suffer from the Night-Eating Syndrome (NES) experience exactly that.

Desynchrony leads to Misalignment

A more complex case of Internal Misalignment is when the Period of one or several circadian Rhythms changes, losing synchrony with other Rhythms and the Sun. Such desynchronized Rhythm would be gradually shifting its position relative to other body Rhythms, creating constant change of the Alignment Pattern.

For example, your Metabolic Rhythm acquires a Period of 25h, while the rest of your body is on the 24h Period. The time when your energy peaks would be delayed by 1h every day.

As a result, on some days, your metabolism would supply enough energy for your daytime workout or cognitive performance. Yet, on other days, it would pump all that energy at night, while you are trying to sleep. Hence, not only the metabolism but your other body functions would suffer.

Typically, Jet Lag is a combination of Desynchrony and Misalignment

About Irina Zhdanova

Irina is the CEO and founder of ClockCoach, and an expert in Sleep Medicine and Circadian Neuroscience