Social Jetlag: What Are the Consequences?

Social jetlag is a relatively new phenomenon that has developed over the past 200 or so years due to modernizations within society. However, the term social jetlag didn't come into existence or receive thorough study until around 2006. Learn about the causes of social jetlag and how it can impact you on both a physical and psychological level. Social jetlag can be more common than you think and cause far-reaching effects on the health of a person if not addressed.

Defining the social jetlag

Social jetlag affects our bodies similarly to travel jetlag. However, instead of operating in another time zone, our bodies are functioning on a schedule that is in conflict or misalignment with our biological clock, or circadian rhythm. Our biological clock determines when we sleep and eat and helps regulate body temperature, heart rate, and hormone secretion. Since all humans are unique, not everyone’s biological clock is in sync with the social clock of societal norms that dictates when we wake up, start working, go to school, or go to sleep. This is because just as there are numerous time zones, there are also a variety of biological clock schedules we refer to as chronotypes.

Conflicting chronotypes

Whenever you've heard someone call themselves a "morning person" or a "night owl," they are referring to their chronotype. Unfortunately, not every chronotype falls in line with mainstream society, regular business or school hours, or an individual's working hours. When a person with conflicting chronotypes forces themselves to operate on the societal clock as opposed to their biological clock, this causes social jetlag. This is because their schedule is not aligned with their body's natural rhythms and cycles. Not only can a person who has social jetlag feel tired and less productive at work, but they can also face health consequences if they do not listen to their bodies to ensure that their chronotype and circadian rhythm are aligned.

Circadian rhythms

A circadian rhythm refers to a person’s biological clock which tells their body when to sleep and secrete hormones, and it also helps regulate functions like heart rate and body temperature. An erratic sleep schedule can disrupt a person’s circadian rhythm, as can operating outside of one’s a natural cycle and chronotype, leading to social jetlag. For example, night shift workers are commonly plagued with social jetlag because they are exposed to artificial light and awake when it’s dark outside. Exposure to the blue lights of computer screens and technological devices late at night can also throw someone’s circadian rhythm off because the blue light tricks the body into thinking it’s light outside. This interrupts the production of melatonin, which we will discuss further in just a moment.

3 different chronotypes:

There are three different chronotypes, and they are termed N-types, M-types, and E-types. E-types prefer to go to sleep and wake up a bit later than N-types and reach their full mental peak in the latter half of the day. On the other hand, M-types prefer to go to bed and wake up earlier and reach their full mental peak during the first half of the day. In comparison, N-types have no preference between morning and evening. Approximately 60% of the population falls under the N-type, while the other 40% is either an M or an E-type. The factor separating M and E-types has to do with melatonin secretion, a hormone produced by the pineal gland that allows the body to fall asleep.

A person tends to be most productive when operating according to their chronotype, but modern society doesn't always allow that. A variety of environmental factors, such as computer screens, can throw a person's circadian rhythm off so that they are not operating in line with their chronotype. This discrepancy with our body's internal clock results in social jetlag. Furthermore, social jetlag can happen to any of the chronotypes and not just those who are M or E-types.

It is also said that a person’s chronotype can influence much more than their preferred times of going to bed, waking up, and being at their mental peak. A chronotype can also influence a person’s attitude, cognitive functioning, lifestyle, personality traits, and athletic performance. For example, M-types are thought to be more agreeable, conscientious, and achievement-oriented while E-types are believed to be more extroverted, neurotic, and prone to mental, mood, and personality disturbances, as well as eating disorders.

How to determine one's chronotype

A chronotype is a person’s innate time preference for waking and sleeping, and so the best way to determine a person’s chronotype is to examine the times they go to sleep and wake up on their days off from work or school, and when they have the most mental and physical energy. For example, m-types have their mental peaks in the morning and their physical peaks in the afternoon, whereas E-types have their mental and physical peaks in the late afternoon and sometimes late at night in extreme cases.

Consequences of a social jetlag

Social jetlag can have short and long-term effects on a person’s health. The short-term effects of social jetlag include:

• Shortened and poor sleep
• Poor work or academic performance
• Impaired alertness
• Abnormal inflammatory status
• Hypertension

The long-term effects of social jetlag include:

• An increased risk for obesity
• Type 2 diabetes
• Metabolic syndrome
• Cardiovascular diseases
• Cancer
• Alzheimer’s disease
• Cognitive impairments

A significant trigger for developing social jetlag is using an alarm clock to dictate when your body wakes up in the morning — ahead of your natural waking time, due to school, work, and social obligations. In industrialized countries, social jetlag impacts a majority of the population, 70%, ranging from one to two hours off their circadian rhythm.

Discover if you have social jetlag:

Researchers developed a simple formula to determine if a person has social jetlag. This involves determining the mid-sleep time — the middle hour of a person's sleep between the time they go to bed and wake up on their days off, then comparing it with their mid-sleep time on work and school days. The difference between the two times (if present) will show how many hours off a person is with their circadian rhythm, AKA: their level of social jetlag measured in hours.

It should be noted that the amount of undersleeping and oversleeping between working and off days should be examined as well. If a person is experiencing a lack of sleep throughout the week, they can build up a sleep debt and will try to make up that debt on their off days. Daylight savings time can even impact a person’s circadian rhythm and lead to symptoms of social jetlag.

During the pandemic, 70% of people stopped relying on their alarm clocks to wake up in the morning since they were now working from home and no longer needed to factor in commute times to work. This resulted in a drastic decline in social jetlag, especially for E-types. This is what led researchers to believe using an alarm clock is a predisposition for developing social jetlag.

Best way to treat social jetlag

The best way to treat social jetlag is by listening to your body and going to bed and waking up at the same time every night, plus or minus 30 minutes, without relying on an alarm clock to wake up. This may require extra sleep at first to help eliminate some sleep debt, however, after a consistent pattern of going to bed and waking up around the same time each day naturally, you should be operating according to your circadian rhythm and combating the negative impacts of social jetlag on your mental and physical health.

Knowing your chronotype is powerful because once you have that information, you can dictate the lifestyle you lead in a way that helps support an optimal level of functioning for greater mental and physical health, and improved work, school, and athletic performance. If you have a difficult time determining your chronotype, you may be an N-type, but seeing an experienced sleep doctor, researcher, or psychologist who specializes in sleep therapy can help you determine your chronotype and give you advice on how to operate at your optimal level in your day-to-day life.