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Jet lag versus social jet lag

Jet lag and social jet lag are two different ways you can disrupt your 24-hour internal body clock called your circadian rhythm. Learn how they differ and how to stay on track with your body’s natural cycle.

What is jet lag and how does it affect you?

Jet lag can occur when you travel quickly across three or more time zones. It tends to be more acute when you’re traveling in an eastward direction. Jet lag occurs because your body’s clock is still synced to your original time zone and hasn’t adjusted to where you’ve traveled. As a result, you can experience sleeping problems like insomnia or early waking, daytime drowsiness, difficulty concentrating, general sluggishness and even stomach problems.

What can you do about jet lag?

Every individual adjusts differently to a rapid time zone change, but there are ways to prepare that can be helpful for minimizing or avoiding jet lag entirely.
  • If possible, arrange your trip to allow a few days to adjust before attending an important meeting or event.
  • Make sure you’re well rested before you leave.
  • Start to adjust your schedule a few days before your departure. If you’re traveling east, eat your evening meal and go to bed one hour earlier each night, starting a few days before (if flying west, make it one hour later).
  • Drink plenty of water before, during and after your flight to counteract the dehydrating effects of dry cabin air. Avoid alcohol and caffeine, as these can dehydrate you as well as affect your sleep.
  • Try to sleep on the plane if it’s nighttime at your destination (and stay away from blue light-emitting electronic devices), but avoid sleep if it’s daytime there.
  • When you reach your destination, try not to sleep until the local nighttime, no matter how tired you are. If it’s daytime, go outside and walk around to get exposure to natural light.
  • Time your meals with local mealtimes, as well, which can also help reset your internal clock.

What is social jet lag?

Maybe you haven’t heard the term before but you’ve likely experienced social jet lag, which is the discrepancy between weekday and weekend schedules (i.e., the difference between circadian and social clocks). If you’ve spent the weekend staying up later and sleeping in to “catch up” on sleep, and then had trouble waking up early on Monday morning, you’ve had social jet lag.

How does it affect you?

While trying to catch up on sleep on the weekend sounds innocent enough, it actually can be detrimental to your circadian rhythm, which needs regularity. Studies show that social jet lag is associated with an increased risk of obesity, diabetes, cardiovascular disease and depression. These effects are not erased by getting more sleep over the weekend because we need adequate sleep each night to properly regulate mental and physical functions.

Think about the transition to and from daylight saving time and how you are affected by a one-hour time change. If you are varying your weekend schedule by more than an hour, you’re making it that much harder to adjust to your weekday schedule.

Social jet lag plays a role in the ongoing discussion of school start times. A proposed later schedule for teens is meant to better align with their natural circadian rhythm while also allowing for a more consistent schedule throughout the week. A University of Washington study of high school students found that those with a later school start time (8:45 am versus 7:50 am) showed less variation between their weekday and weekend sleep times, thus decreasing their social jet lag and making it easier to make it to Monday morning class.

What can you do about it?

To avoid those Monday morning blues, try not to vary your weekend schedule by more than an hour, if possible. And make sure you get seven to nine hours of sleep on weekdays, as well as on the weekend.
Sources: Journal of Clinical Sleep Medicine, Mayo Clinic, Sleep Foundation, Dunster, GP et al. (2018) Sleepmore in Seattle: Later school start times are associated with more sleep and better performance in high school students, Science Advances.

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