As the summer winds down and the back-to-work season begins, many people face the challenge of readjusting their schedules after a month-long vacation. This transition period can exacerbate social jetlag, a misalignment between our biological clocks and social schedules. At NEM Health, a digital healthy longevity clinic focusing on optimizing the healthspan of our clients, we understand the importance of addressing social jetlag to maintain health and wellness during this crucial time.
In this article we cover:
- Understanding Social Jetlag
- The Science Behind Social Jetlag
- Health Implications of Social Jetlag
- The Back-to-Work Challenge
- Strategies to Prevent Social Jetlag
- NEM Health’s Commitment to Chronic Disease Prevention
Understanding Social Jetlag
Humans have an internal body clock, known as the circadian clock, which operates on a nearly 24-hour cycle (1). This clock regulates various bodily functions such as sleep, body temperature, heart rate, metabolism, and hormone secretion, helping organisms anticipate daily environmental changes. Light is the primary signal that resets the circadian clock each day.
Over the past 200 years, modernization has drastically altered human lifestyles, introducing widespread artificial light, 24/7 work schedules, and rapid travel across time zones. While these advancements have increased convenience, they have also led to circadian misalignment—a mismatch between environmental time and the body’s internal clock (2). This misalignment is commonly seen in people experiencing jetlag or working night shifts.
Circadian misalignment disrupts the body’s physiological processes, leading to short-term effects like poor sleep, reduced alertness, and hypertension. Long-term consequences include a higher risk of obesity, diabetes, metabolic syndrome, cancer, cardiovascular diseases, cognitive impairments, and Alzheimer’s disease (1).
A less obvious but significant form of circadian misalignment is social jetlag, a term coined by Wittmann in 2006 (3). Social jetlag refers to the discrepancy between an individual’s internal biological clock and social obligations, such as work or school schedules. Unlike regular jetlag caused by crossing time zones, social jetlag is a chronic condition that arises from the ongoing conflict between our natural circadian rhythms and societal demands. In industrialized countries, about 70% of the population experiences social jetlag, ranging from 1 to over 2 hours (1).
The Science Behind Social Jetlag
Social jetlag is measured by the difference in mid-sleep times between workdays and free days. This misalignment is particularly pronounced in individuals with late chronotypes (night owls) compared to early chronotypes (morning larks) (5). Chronotypes, which can change with age, influence the degree of social jetlag a person experiences.
The phenomenon of social jetlag is relatively modern, emerging with industrialization, which drastically altered our exposure to natural light. Reduced daylight exposure and increased artificial lighting have pushed our circadian clocks later, while social demands often require early start times, leading to widespread social jetlag.
Health Implications of Social Jetlag
Numerous epidemiological studies have demonstrated the adverse health effects of social jetlag. These include:
Metabolic Disorders
Social jetlag is associated with obesity, type 2 diabetes, and metabolic syndrome. Irregular sleep patterns disrupt hormonal balance and glucose metabolism, contributing to these conditions.
Research has shown that social jetlag significantly impacts metabolic health. Studies indicate that individuals with more than 2 hours of social jetlag exhibit higher fasting cortisol levels, low HDL cholesterol, high triglycerides, and elevated total cholesterol, triglycerides, and fasting glucose levels, all of which are metabolic risk factors (6). These metabolic changes are partly due to unhealthy behaviors associated with social jetlag, such as consuming more high-calorie and high-sugar foods and adhering less to healthy dietary patterns. Additionally, social jetlag is linked to sleep deprivation, higher tobacco use, reduced physical activity, prolonged eating durations, and later food intake times (1). Experimental evidence suggests that social jetlag combined with a high-calorie diet exacerbates metabolic disturbances, increasing the risk of metabolic syndrome.
Several studies have found that social jetlag is linked to higher Body Mass Index (BMI) and waist circumference, markers predictive of obesity (1).Research has also linked social jetlag to an increased risk of diabetes. The New Hoorn Study found that 2 hours of social jetlag doubles the risk of pre-diabetes and type-2 diabetes (7). Additional studies have shown that social jetlag is associated with abnormal carbohydrate homeostasis, higher fasting insulin levels, and greater insulin resistance (8). Despite some limitations, including reliance on self-reported sleep data, these findings consistently suggest a connection between social jetlag and diabetes, highlighting the importance of circadian alignment in metabolic health.
Cardiovascular Health
Social jetlag is suspected to increase the risk of cardiovascular diseases, as the stress of misaligned sleep schedules can potentially lead to hypertension and other heart-related issues.
Several studies have investigated how social jetlag affects the heart and blood pressure. For instance, one study found that those with more social jetlag had higher resting heart rates, indicating potential cardiovascular issues (6). Another study found an association between social jetlag and altered heart rate, suggesting a higher risk of heart problems (9). However, some studies have not confirmed these findings, possibly due to different methods of measuring social jetlag.
In addition, shift work, which causes habitual circadian disruption, has been linked to cardiometabolic diseases, although it is unclear if day-to-day circadian dysregulation adds risk beyond poor sleep and behaviors. A study examining whether chronotype and social jetlag are associated with cardiovascular disease risk factors in healthy midlife adults working day shifts found that social jetlag was linked to lower HDL cholesterol, higher triglycerides, fasting plasma insulin, insulin resistance, and adiposity, even after adjusting for sleep quality, depressive symptoms, and health behaviors (8). Evening chronotype was also associated with lower HDL cholesterol. Since heart rate is an important indicator of heart health, future research is needed to clarify whether social jetlag truly impacts cardiovascular health, as misaligned sleep timing may increase metabolic risk factors for diabetes and cardiovascular disease.
Mental Health
Social jetlag can exacerbate symptoms of depression, anxiety, and overall mental well-being (1). The chronic sleep deprivation and stress associated with social jetlag negatively impact mental health.
The Back-to-Work Challenge
Returning to work after a long vacation, especially the month-long break common in Sweden, can intensify social jetlag. The sudden shift from a relaxed vacation schedule to a structured work routine can disrupt sleep patterns, leading to increased stress and anxiety. This transition period is critical, as it can set the tone for the upcoming months.
Strategies to Prevent Social Jetlag
Reducing social jetlag is crucial for preventing chronic diseases and promoting longevity (4). Here are some strategies to help you as you transition back to work:
- Gradually Adjust Your Sleep Schedule: Start adjusting your sleep schedule a week before returning to work. Gradually shift your bedtime and wake-up time by 15-30 minutes each day to align more closely with your work schedule.
- Optimize Light Exposure: Increase exposure to natural light during the day, especially in the morning. Limit artificial light, particularly blue light, in the evening to promote better sleep.
- Create a Sleep-Friendly Environment: Ensure your bedroom is dark, quiet, and cool. Invest in comfortable bedding and minimize disruptions.
- Practice Good Sleep Hygiene: Develop a relaxing bedtime routine, avoid heavy meals and caffeine before bed, and engage in regular physical activity.
- Take Advantage of Flexibility: If possible, use any available flexible work hours or remote work options to ease the transition and reduce stress.
- Manage Stress and Anxiety: Incorporate stress-reducing activities such as mindfulness, meditation, or yoga
Social jetlag is a significant yet often overlooked factor in the development of chronic diseases. As the back-to-work season approaches, it is crucial to address this issue to ensure a smooth transition and maintain overall health. By understanding its impact and implementing strategies to reduce it, we can improve our health and quality of life. At NEM, we are committed to guiding you on this journey, helping you achieve better sleep and optimize your health.
NEM Health’s Commitment to Chronic Disease Prevention
At NEM, we are dedicated to preventing age-related chronic disease and optimizing the health of our clients through personalized health interventions. By addressing social jetlag and promoting healthy sleep practices, we aim to enhance overall well-being and longevity.
We recognize the importance of quality sleep and its impact on overall health. Our personalized approach includes assessing individual sleep habits, leveraging wearables to track patterns, and providing tailored guidance to enhance sleep quality. We emphasize the significance of consistent sleep schedules, relaxing bedtime routines, and creating optimal sleep environments.
With all this data, we assist with interpretation and provide support to help our clients make informed decisions about their health and well-being. Our approach includes:
- Personalized Sleep Assessments: Using wearables to assess individual sleep patterns.
- Tailored Recommendations: Offering customized advice and interventions to improve sleep quality and reduce social jetlag.
- Continuous Monitoring: Providing ongoing support and monitoring to ensure long-term adherence to healthy sleep practices.
By integrating these strategies, we aim to contribute to our clients’ overall health and longevity.
