Social jet lag
What is social jet lag?
Social jet lag is the fatigue and circadian disruption that occur when our social sleep schedule clashes with our body’s biological clock. In simple terms: our internal rhythms (chronotypes) suggest one timing for sleep and wake, while our lifestyle (work, study, social life) demands another.
We all vary in chronotype (early birds, night owls, or somewhere in between). When we push our sleep–wake times away from our internal preference, for example, staying up late, sleeping in on weekends, or changing wake times dramatically, the misalignment may lead to a form of “jet lag” that occurs without travelling across time zones.
Why is this a concern?
A growing body of research suggests that greater mismatches between sleep timing on workdays and free days are associated with less optimal sleep quality, mood variation, cognitive differences and some metabolic outcomes.
For example:
• A recent review found that in young people (ages 10-24), social jet lag of two hours or more was linked with higher odds of depressive symptoms. BioMed Central
• Other studies indicate that adolescents with higher misalignment show differences in brain connectivity and cognitive performance. OUP Academic
• It’s important to note these are associations, not proof of causation, many of the studies are observational. Cambridge University Press & Assessment+1
How common is it?
It’s more common than you might think. Some estimates suggest around two‐thirds of people experience at least one hour of social jet lag per week, and about one‐third may experience two or more hours… comparable to regularly flying across several time-zones!
What can we do?
While occasional sleep‐ins are unlikely to be harmful, especially if you have sleep debt to recover, maintaining a regular sleep pattern can help your internal clock align better with your daily schedule.
Here are some strategies:
1. Try to keep wake‐up times consistent across workdays and free days.
2. Minimise exposure to blue light (screens, TVs) in the hours before bed.
3. Get outside in bright daylight soon after waking (or eat breakfast by a bright window).
4. When possible, allow your wake‐up time on days off to align as closely as possible with your usual weekday wake time.
These steps may support your circadian rhythm over time.
References
Sun S, Yang Y, Yu F et al. “Social jetlag and depressive symptoms among young people: systematic review and meta-analysis.” BMC Psychiatry 2025. BioMed Central
Yang N, Picchioni D, Duyn JH. “Effects of sleep-corrected social jetlag on mental health, cognitive ability and brain functional connectivity in early adolescence.” Sleep 2023;46(12):zsad259. OUP Academic
Roenneberg T, et al. “How can social jetlag affect health?” Nature Reviews Endocrinology 2023;19:383-384. Nature
“Association between social jetlag and poor health and its nutritional mechanisms.” Public Health Nutrition 2024. Cambridge University Press & Assessment
Wittmann M, Dinich J, Merrow M, Roenneberg T. “Social jetlag: misalignment of biological and social time.” Chronobiology International 2006;23(1-2):497-509. Dove Medical Press
Disclaimer: This information is not intended to be used as medical advice or a substitute for your own practitioner’s advice, nor is it intended to be used for diagnosis or treatment for any illness/disease.
