Why does my son ALWAYS sleep for 40 minutes?

I've moved him into his crib for naptime (as opposed to in his swing, the sling, or just on me) because he's almost 4 months and I want to start a routine for him. But he other sleeps only 40 minutes. Every single time. He's usually still tired when he wakes up, but can't or won't go rear legs to sleep. If I move him into his swing, he'll sometimes fall back asleep and sleep for another hour or two.

My daughter did this same thing. We call it the 40 minute hump. If she got past it, she'd have a nice rest. But she rarely got past it.

I really want to aid him sleep longer. He's waking up cranky and tired.

Has anybody else experienced this? What did you do?
Its porobably cause he still on milk 4months. Try giving it the cereal milk she/he be more fuller that way she/he sleep longer.
Oh, yes, we experienced the same thing. EXACTLY indistinguishable thing. My son had the 40-minute nap until he be around 6 months old. Now he's almost 10 months and naps for 2-3 hours twice a day. I don't know why this happen to young infants -- I guess 40 minutes is just how long it takes them to complete a sleep cycle and they rouse up and can't soothe themselves back to sleep until they are a little older and swot up to self-soothe. But that's just my guess.

Anyway, good luck!
Mine did the same thing from 4 months-8 months. He would sleep 45 minutes, wake up cranky and it took me 30 minutes to achieve him to go back to sleep, and he would sleep another 45 minutes. Routine helped. Once I committed to staying home at rest time to make sure his nap happened like way every day, not always at like time but when he was tired, it only took a couple weeks for him to stop waking until he be rested.

When he woke after 45 minutes I rocked with him, while he screamed sometimes, until he passed back out and he would sleep another 45 minutes. After a couple weeks he basically slept the full 1 hour 15 minutes instead but if I messed up our routine by being out and he got a small nap surrounded by the car it was all out the skylight for a good week after that. After 8 months, give or take, he be more flexible. I could either rock with him until he passed back out or I could hold a fussy awake baby which stank but it passed. I hated that hump, I always watch the clock waiting to see if he would wake right at 45 minute or go the full time. He now have a 1 hour 15 minute hump at 16 months old but typically wakes rested. If he passes 1 hour 15 minutes I know he will siesta a full 2 hours.
Does he sleep in a quiet, cloudy room? Maybe it's just a nap he's taking. I play music for my baby when she go to sleep. It is an hour long CD. It seems to help her drift into a deeper sleep.

Or conceivably your baby is going through a growth spurt.
Isn't a minute a wink = 40 winks?
My niece had a similar issue. She'd sleep on a swinging holder longer than in her crib. The solution that everyone came to was buying a rocking crib and keeping her more snug surrounded by her blankets.
Yes! With both my kids. But my kids didn't wake up tired or cranky.
It's clear that he is uncomfortable surrounded by his crib so I would either 1) Buy a new crib or 2) Add a layer or 2 of blankets and see if anything change.
every one is different?
my now 2year old lil sis used 2 do that and me give her warm milk and
read 2 her until she dozed off again but if it doesn't work for u i would recommend a pediatrician's help for sleep methods
A baby will develop his own sleep/wake template, and as long as we hold him on our chest he will get use to it and only sleep that way, if we put him within the swing he get use to it, in order for him to develop his own guide we have to find a quit place on the bed for him and when he get sleepy we have to lay him down and than that become his pattern and he will sleep longer.
atleast you receive 40 minutes i get 15 at the most
Answers:    It all has to do next to your bubs sleep cycles.

Most babies go through a sleep cycle every 40-50 minutes then stir/wake. Your bub has not nonetheless learnt to put himself back to sleep so wakes up.

When he wakes/stirs, leave your job him for a while to see if he will self settle. You may need to go in at first and soothe him support to sleep (pat/stroke head/put dummy in if he has one). Do not pick him up or he will expect this all the time.

I hold done this with my 3 month old and I think she finally have the hang of it. We have had a routine from the outstandingly beginning (although not terribly strict). Not all nap are of the same length (morning 1 hours / lunchtime 1.5 - 2 hours and afternoon 45 minutes) and she is now sleeping from 7pm to 3am every night afterwards until 6.30am.

Babies love routines as they know what to expect next. Good luck!
It's because a babies sleep cycle lasts for 40 minutes. You know how here is (roughly, can't remember exact order) light sleep, REM sleep, heavy sleep... then it starts adjectives over again? Adults have the same cycle and everyone wakes up slightly until that time the cycle starts over. Just adults get themselves back to sleep so quickly, they don't even remember half-waking most of the time. Babies aren't as worthy as adults at going straight back to sleep... which is way they wake repeatedly and sleep for shorter periods. There's not much you can do other than wait until he's developmentally equipped to get himself back to sleep without a fuss.

ETA: Just considered necessary to suggest a blackout blind. We have on in my sons room and he naps 1-2 hours twice a afternoon (he's nearly 11 months) and sleeps 12 hours through the night. Whenever we stay with relatives, he wakes up at the crack of daybreak and simply refuses to nap unless it's pitch black. I believe the blackout blind is to thank for his good sleep customs!
Your son is actually a robot. Programmed to sleep for 40 minutes to trick you into believing he is a human.
just throw them out the window and forget you ever gave birth, your duration would be sooooo much better

Related Questions:
When a child starts solids, how much breast milk does he stipulation contained by a 24-hour time of year?   At what age did your babe consistently decline asleep on their own and sleep adjectives hours of darkness?   Mommies, do you mind your own business?   Did you devour Deli meat when you be pregnant?   5 week infirm infant coughs and she's not sick?  
  • My son WAS sleeping really resourcefully at hours of darkness... What happen?
  • Do they testing adjectives babies routinely for Hiv when near born?
  • When did you set up your baby's nursery and find geared up for the arrival?