We’ve all done it – stayed up late on a Friday night to binge watch Netflix, or slept in until close to sunrise after a Saturday night out. While the occasional late night is unlikely to cause much harm, a consistently sporadic sleep schedule can wreak havoc on your internal body clock. The phenomenon which occurs when you go to bed and wake up later on weekends than during the week is called social jetlag.
Unfortunately, social jet lag carries far more serious health implications than you may think. For example, a recent clinical trial revealed that just one hour of social jet lag has been associated with an 11% increase in the likelihood of heart disease. 
What Is Social Jet Lag?
Social jet lag refers to the symptoms of jet lag – feeling tired due to a disrupted sleep schedule – that occur due to socializing late at night.
This term was initially coined by Till Roenneberg, Ph.D., a professor at the Institute of Medical Psychology at the University of Munich. He estimates that approximately two-thirds of the working population fall into this category as they have different sleep patterns on the weekend than they do during the week. 
He explained that since most people don’t bother setting an alarm on the weekend, this results in people waking up an hour or two later than they do during the week. Even though waking up without an alarm may be more aligned with the body’s natural rhythms, the inconsistency confuses the internal body clock.
This problem is then further exacerbated by the additional delay in bedtime, which leads to an even more out of sync sleep schedule.
Symptoms of Social Jet Lag
Social jet lag has been associated with poorer health, worse mood, and increased sleepiness and fatigue.
Furthermore, according to some research people with chronic social jet lag are more likely to:   
- Be overweight – for every hour of social jet lag, the risk of being overweight or obese rises by approximately 33%
- Become diabetic
- Have hypertension
- Depressed or anxious
- Consume above average amounts of alcohol, caffeine, and/or nicotine
How To Treat Social Jet Lag
According to Sierra B. Forbush, the lead author of a study on social jet lag at the University of Arizona, the key to treating social jet lag is to understand that it’s not sleep duration alone that matters, but sleep regularity.  Sticking to a consistent sleep schedule could be a simple and effective preventative measure for helping alleviate a host of associated health issues such as heart disease, obesity and chronic fatigue.
That being said, although it sounds easy, we know it’s not always simple to stick to the same sleep schedule on weekends. Late night social obligations are a reality, and attempting to wake up at the same time on the weekends can cause further sleep debt.
There are some guidelines that can be followed in order to minimize social jet lag:
Avoid Sleeping In
Similar to any workday, aim to get 7-9 hours of sleep on the weekend. Resist the urge to sleep more than 9 hours on the weekend just because you can. Excessive sleeping will not reverse sleep debt and may lead to more fatigue.
Get Strategic Daylight Time
According to Roenneberg, if you have trouble falling asleep earlier at night, you should try to get more sunlight in the morning and avoid sunlight in the afternoon and evening. In contrast, if you need to stay up later at night, get more sunlight in the afternoon and evening so that your body clock can adjust better the next day.
Cultivate Social Mindfulness
Mindfulness refers to being present in the moment while acknowledging and accepting all thoughts, feelings and body sensations. Practising mindfulness can help you tune into how you feel at the start of an evening out. Check-in with yourself and ask: Are you tired and would you rather call it an early night? Is the Netflix binge worth the headache and grogginess the next day?
Adjust Your Weekday Schedule to Your Chronotype (If Possible)
If you happen to have an evening chronotype, consider ways to adjust your weekday schedule to align more naturally with your body’s internal clock. If you are a university student, take classes later in the day. If you have an office job, consider moving closer to work and reducing your commute time, or negotiating a later start and end time.
 American Academy of Sleep Medicine. (2017, June 5). Social jet lag is associated with worse mood, poorer health and heart disease: Delaying your sleep schedule on weekends has health consequences. ScienceDaily. Retrieved July 9, 2018 from www.sciencedaily.com/releases/2017/06/170605085326.htm
 Goodman, B. (2018). Do You Have ‘Social Jet Lag’?. [online] WebMD. Available at: https://www.webmd.com/sleep-disorders/news/20120510/do-you-have-social-jet-lag#1 [Accessed 9 Jul. 2018].
 Wittmann, M., Dinich, J., Merrow, M. and Roenneberg, T. (2006). Social Jetlag: Misalignment of Biological and Social Time. Chronobiology International, 23(1-2), pp.497-509.
 Wong, P., Hasler, B., Kamarck, T., Muldoon, M. and Manuck, S. (2015). Social Jetlag, Chronotype, and Cardiometabolic Risk. The Journal of Clinical Endocrinology & Metabolism, 100(12), pp.4612-4620.