As we've been at home during the pandemic our schedules have shifted, with many children going to bed and waking later than they would under normal circumstances. When a child's sleep schedule is mismatched from their social schedule a phenomenon called social jet lag can occur. You have probably experienced actual jet lag when you've traveled across time zones. The biological underpinnings of social jet lag are the same as with actual jet lag and it can cause sleep loss and daytime crankiness for your child, which can lead to a sleep regression.
What is social jet lag?
The term 'social jet lag' was coined by a German researcher, Professor Till Roenneberg, who observed that many people sleep late on weekends and then have trouble shifting back to a weekday work schedule. His research revealed that when an individual stays up late or sleeps in for a few nights in a row, the circadian rhythm (the body's internal clock) responds by shifting the drive to sleep later, thus creating a mismatch between the social time that one needs to be awake for work activities on weekdays and the body's drive for sleep. While the way social jet lag has unfolded in babies, toddlers, and preschoolers during the pandemic is a bit different than these weekly changes in adults, the underlying cause of the disruption is the same.
The Science Behind Circadian Rhythm in Babies and Toddlers
We each have an internal clock that's a little longer or a little shorter than 24 hours. In order to stay aligned with the day-night cycle, the circadian rhythm must be adjusted. The way that the circadian rhythm is reset is through our exposure to light each day. Exposure to light at different times of day does different things; light in the evening shifts the drive to sleep and wake later, while light in the morning shifts the drive to sleep and wake earlier. The influence of light is strongest during normal sleep times, when the body would otherwise be exposed to darkness. This varying response to light exposure allows our bodies flexibility and allows us to respond to variations in seasons and travel across time zones. Notably, recent research suggests that the circadian response to light in young children is much more sensitive than in adults.
The circadian rhythm is one of two sleep drives (here's more info on sleep basics), but it also controls the drive to be awake and many other aspects of biological function. The strongest drive to be awake happens right before your child's normal bedtime (a time called the wake maintenance zone). This is why some children seem wide awake or even a little bit hyper right before bed.
These features of the circadian rhythm mean that staying up late for a few days in a row will be interpreted by the body as a change that requires a sleep shift. Practically speaking, this means that if you relaxed your child's schedule during the summer, enjoying later evening family time and later rise times in the morning, when it's time to get your child up to go to daycare or school, your child probably won't be ready for sleep at her normal bedtime. In fact, she might be wide awake and hyper at that time because her circadian rhythm has shifted her strongest drive to be awake to be aligned with her pandemic bedtime.
How do you prepare your child's sleep for a new daycare or school schedule without inducing social jet lag?
During the pandemic your child's sleep might have drifted to a bedtime of 8:00, 9:00, or even 10:00 PM. If you need your child to be awake at 6:00 AM to get ready to go to daycare or school, then you will need to put your child down earlier to ensure she gets enough sleep. Unfortunately, as mentioned above, if you try to move your child's bedtime earlier all at once, then you'll be putting your child down at a time she probably can't fall asleep. As a result, you'll end up with a lot of bedtime crying or resistance. Here's how to make that adjustment with minimal pain:
Determine how much sleep your child needs at night and identify target bed and wake times.
If you aren't sure how much your child should be sleeping, then check out our age by stage sleep chart for guidance.
Start at least one week before you need your child to be on a new schedule.
The bigger difference between your pandemic schedule and your child's daycare/school schedule, the sooner you should start.
Starting at least one week before your child's new schedule, dim the lights and cut out screen time in the evening beginning at your child's target bedtime.
For example, if you would ultimately like your child to be in bed at, say, 7:30 PM each day, but she's going to bed at 9:30 PM, then close the curtains and dim the lights starting at 7:30 PM even if you aren't going to put her down until later.
Wake your child 15-30 minutes earlier each day.
Light resets the circadian rhythm and will shift your child's bedtime earlier. As a result, it's really important to make sure you open the curtains and allow your child to spend those first 30 minutes awake in a well-lit environment.
Put your child to bed 10-20 minutes earlier each night.
If your child takes more than 20 minutes as you shift earlier, then don't move bedtime earlier the next night. Keep bedtime stable until your child starts falling asleep faster. You may keep waking your child progressively earlier even if you aren't moving bedtime earlier on those days.
If your child naps, then move naps earlier in tandem with your child's wake time.
Keep shifting until you reach your desired bed and wake times that adjust your child for the new schedule.
Once you get your child reset to a schedule that suits your social schedule on weekdays it's best to keep a stable schedule as much as possible, even on weekends. You don't have to be rigid, but keeping bedtime and wake time within about 30 minutes every day of the week should prevent social jet lag from happening.
If your child has other sleep issues, like frequent night waking or nap trouble, then you may need to address those issues before you can determine the impact of social jet lag. Check out our Resource Blog and webinar series for more help or book a consultation with us for personalized support.
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.
Hale, L., Kirschen, G.W., LeBourgeois, M.K., Gradisar, M., Garrison, M.M., Montgomery-Downs, H., Kirschen, H., McHale, S.M., Chang, A.M. and Buxton, O.M., 2018. Youth screen media habits and sleep: sleep-friendly screen behavior recommendations for clinicians, educators, and parents. Child and Adolescent Psychiatric Clinics, 27(2), pp.229-245.
Akacem, L.D., Wright Jr, K.P. and LeBourgeois, M.K., 2016. Bedtime and evening light exposure influence circadian timing in preschool-age children: A field study. Neurobiology of sleep and circadian rhythms, 1(2), pp.27-31.
Minors, D.S., Waterhouse, J.M. and Wirz-Justice, A., 1991. A human phase-response curve to light. Neuroscience letters, 133(1), pp.36-40.