top of page

The Fall Daylight Saving Time “slam shift” to prevent early waking

The Daylight Saving Time “slam shift” to prevent early waking

Didn't think it was a big deal? Your first child handled it fine, so you assumed your second would be the same? Too tired to care?

We know there are people out there who either just didn’t realize that the “fall back” DST transition was happening, or are just too darn busy and overwhelmed to care. However, this may become a big deal if your baby or toddler starts waking up an hour early!

Well, for those of you who haven’t had the time to adjust your child slowly, we present..... the “Slam Shift.”

Please note: If you have a little baby and you do have time to make the shift gradually (recommended), then check out our blog on shifting more slowly.

The Science

The fall Daylight Saving Time transition is essentially the same as traveling one hour westward. That's right, it's like jet lag!

Essentially, you’ll need to shift your child’s bed and wake time one hour later in order to achieve the same clock time schedule that you had before the time change. Moving bedtime is fairly easy because you just keep your child up. Moving wake time is not so easy, because babies and toddlers don’t “sleep in” when they are sleep-deprived like older children and adults do.

The circadian rhythm is somewhat flexible and makes small adjustments every day, even when you stay in the same time zone, because the circadian rhythm is a little longer than 24 hours for most people. This means that your child’s (and your) circadian rhythm has to make a small adjustment to the clock every day in order to keep biological time in synchrony with the 24-hour day. Big adjustments of an hour or more are much harder for the circadian rhythm to adjust to, which is why it's helpful to do a few things to help your child adjust to the time change.

How does the circadian rhythm reset?

The circadian rhythm resets through the timing of your daily light exposure through your eyes (your eyes have to be open for it to work). If you weren’t exposed to light in the morning, then your biological bedtime and wake time would start to drift later and later every day.

When you travel across time zones, the same adjustment process will happen as happens for DST, but with actual jet lag, you’ll have the benefit of later sunlight exposure in the evening relative to your internal circadian rhythm. When you shift sleep later for the fall DST transition, you do not have the benefit of extra bright light in the evening to help your child’s body make the shift. In fact, it will now be darker much earlier in the evening. This means that you have to compensate by carefully controlling your child’s exposure to light in the evening and darkness in the morning. Light in the morning shifts sleep earlier, so if you want to allow your child to adjust to a later wake time, then you have to keep it dark in the morning. Light in the evening shifts sleep timing later, so to achieve a later bedtime and wake time, you have to expose your child to bright light in the evening.

The Slam Shift

What is a slam shift, you ask? Well, it’s basically just making a big jump and moving your child’s bedtime an hour later all at once. Some people will naturally follow the clock and put their children down at what amounts to an hour later on the day of the time change because that is socially normal. We’re here to tell you that can work just fine, but there are a few caveats.

  1. Keep the lights bright in the evening before bed. Remember, later bedtime without bright light exposure in the evening will not lead to a later wake time. Even if you do a slam shift, you really need to keep those lights bright in the evening until about 20 minutes before the NEW bedtime.

  2. Keep it dark in the morning until your child's target wake time. Your child will not immediately sleep later after you shift his/her bedtime an hour later. This means that your child will likely wake at his/her typical wake time despite the hour later bedtime. When your child wakes an hour early on those first few mornings, you’ll still want to keep it dark until your new, desired wake-up time.

    1. Play in the dark in the morning. Be prepared to go to your child's room and play by the light of a nightlight. This is a great time to engage in activities like reading a book with a flashlight, making shadow puppets on the wall, playing 'hide and seek' by using a flashlight to 'find' toys in your child's room.

    2. Use a morning cue. If your child is older than 18 months old, then introduce a lamp or nightlight plugged into a smart outlet or outlet timer set to your child's target wake time. Play with your child until the morning light cue turns on and then celebrate, leave the room and go start your day.

  3. Repeat steps 1 and 2 until your child starts sleeping later. If your child does not start sleeping later after about a week, then you may need to do some morning sleep training. Our sleep class can help you identify a sleep training plan that will suit your child if you have a baby. If you have a toddler or preschool-aged child, then we can work with you to create a plan in a personal consultation.

Real-World Example

Mateo is two years old. He normally takes one nap after lunch from about noon until 2:00 pm. His normal bedtime is 7:00 pm and he normally wakes around 6:00 am.

Saturday to Sunday

On the Saturday before the time change, his parents put him down at 7:00 pm as normal. On Sunday after the clocks change, he wakes at 5:00 am new time (his usual 6:00 am old time). His dad goes into his room and reads to him in the dark using a dim flashlight. Mateo gets bored of reading at 5:30 am and his dad uses the flashlight to make shadows on the wall with his hands. At 5:45 am, they use the flashlight to find Mateo's diaper and clothing and get Mateo ready for the day. At 6:00 am, his room lamp turns on. His dad points at the lamp and says, "Mateo, Look! It's morning" and they leave the room to get breakfast. On Sunday, Mateo is sleepy at 11:00 am (which is the same time as his usual noon nap time from the day before). His parents keep him up until noon (new time) by taking him to the park and keeping him distracted in the morning. They are careful not to allow a catnap in the stroller on the walk home. He cries a little going down because he's overtired and needs a little extra soothing to settle, but sleeps from 12:00 until 2:00 pm as usual. That evening, his parents bring extra lamps into the living room to make the room really bright where they play with him until 6:30 pm when they start his bedtime routine. He gets sleepy and a little cranky at 6:00 pm (which is the same as 7:00 pm in his body), but his parents keep him up until 7:00 pm.


Mateo wakes up at 4:50 am on Monday. His parents are dismayed that he is up so early, but they remember that children don't wake at the same time every day and that his body is still on old time and to Mateo, it feels like 5:50 am. Once again, dad keeps Mateo in his room, playing in the dark until 6:00 am. Mateo is still pretty tired in the morning, but they keep him up until 11:45am for his nap, making sure not to allow catnaps. He naps until 2:15 and his parents wake him at that point. He's had a 2.5 hour nap today and they want to keep him on schedule. Once again, that evening, they keep him in bright light. Mom takes Mateo to Target (where the lights are super bright!) late that afternoon as the sun is going down, and then they play at home (with all the lamps on) after dinner. His parents put him to bed at 7:00 pm.


Mateo wakes up at 5:10. It doesn't feel like Mateo is making any progress, but his parents keep him in the dark until 6:00 am, they put him down at noon, keep his nap its usual length, and then they put him to bed at 7:00 pm after playing in bright light in the evening. Mateo has lost a few hours of sleep over the past days due to the early waking and on Tuesday night, he wakes up in the middle of the night. His parents respond by briefly checking on him as they do when he has sleep regressions and he goes back to sleep after about 15 minutes.


On Wednesday morning, Mateo wakes up at 5:30 am. His parents are happy that he's started to sleep a little later. They keep him in the dark until 6:00 am, put him down for his nap at noon, keep him in bright light in the evening and then put him down for bedtime at 7:00 pm.


On Thursday morning, Matteo sleeps until 5:40 am. His parents keep him in the dark until 6:00 am, put him down for his nap at noon, keep him in bright light in the evening and then put him down for bedtime at 7:00 pm. He seems a bit more rested today and is having an easier time making it to naptime and bedtime.


On Friday morning, Matteo sleeps until 5:40 am again. His parents keep him in the dark until 6:00 am, put him down for his nap at noon, keep him in bright light in the evening and then put him down for bedtime at 7:00 pm.


On Saturday morning, Matteo sleeps until 5:40 am again. His parents are worried that he's getting too excited about having morning company and so they check in on him at 5:45 am and say "It's still night time. Daddy will come back when your lamp turns on." Mateo isn't happy about that, but his parents watch him on the monitor and go to him at 6:00 am. At that point they say, "good morning" and take him to the living room for some cuddles before breakfast. Once again, they put him down for his nap at noon, keep him in bright light in the evening and then put him down for bedtime at 7:00 pm.


On Sunday morning, Matteo sleeps until 6:00 am and is back to his normal schedule by the clock. His parents keep him in his dark room until 6:00 am every morning, they put him down for naps at noon, and for the next week they keep the lights bright in the evening before his bedtime at 7:00 pm.

Important notes

Obviously the example above is one of many ways this could unfold, but we hope you can use it as a general guide for your toddler.

Please note that a slam shift is generally fine for toddlers, but not so great for babies. For babies, we would generally recommend that you take things slowly, using these instructions. Remember, sleep loss is a side effect of shifting sleep later. The younger your child the bigger the potential for problems if you change things too quickly. Making a big jump in your baby’s sleep could lead to a chain reaction causing your baby to lose too much sleep each night. Remember, even though you put your baby down later, that does not mean that he or she will wake later in the morning at first. A later bedtime will almost always lead to no change in wake time for the first few days.

And for the kids who are going to bed TOO late.....

If your child is going to bed later than you would prefer, then simply do not try to shift your child for DST.

For example, if your child persistently struggles with falling asleep when you attempt bedtime and if you have to wake your child in the morning, then his/her circadian rhythm may already be shifted late. If that sounds like what is happening with your child, then don't make any adjustments. After the time change, your child should be able to fall asleep at their usual clock time, faster. That said, sometimes behavioral issues will cause sleep problems to reemerge. Check out our blog on solving bedtime battles and know that we’re always here to help if you need us.

bottom of page