Japanese researchers have uncovered a specific formula that could help parents get a crying infant to sleep.
In recent study published in the journal Current Biology, scientists found that if a caregiver carries a crying infant for five minutes, then sits with the baby for eight minutes, they can successfully soothe the child, and possibly get them to sleep.
Researchers used baby EKG machines and video cameras to compare changes in an infant’s heart rate and behavior when they’re carried, held by a sitting parent and pushed in a stroller — all common behaviors caregivers use to soothe a crying infant. They found that if a child is carried for five minutes, their heart rate will decrease. If the caregiver stopped walking with the child in their arms, or if they turned abruptly, the child’s heart rate would increase.
Scientists concluded that walking with a crying infant in your arms for five minutes (without any sudden turns), then holding them while sitting still for eight minutes, will help a crying baby go to sleep.
The same study found that the firve-minute walk, eight-minute sit routine only works to promote sleep if the baby is crying — the same method did not have a similar effect when babies were already calm beforehand.
“People don’t study parenting issues too much in this field, but ordinary people really suffer. This is such an important issue that is not really (a focus) of researchers, which is paining for me as a researcher but also as a mother,” Dr. Kumi O. Kuroda, the researcher at the RIKEN Center for Brain Science in Japan who developed the study, told TODAY Parents.
One 2019 study of 4,600 German parents published in the the journal Sleep found that many parents won't get a decent night's sleep for up to six years after their child is born. A 2016 study published in the Journal of Research in Medical Science found a link between sleep deprivation and postpartum depression in new parents.
The study is not meant to deter parents from trying other methods to help their baby stop crying and sleep, Kuroda said. Instead, she said she hopes that parents will use "all their options."
"If you know this method in advance, you can try it before you start wondering what is wrong with your baby if they're not sleeping," she said. "You can just try it — most parents will spend five minutes walking with their babies during the day. Everyone does it it, it's safe, and it's just a useful option that someone may want to try."
Kuroda said the study also highlights the importance of what is known as the "transport response" — in human infants, the sensation of being carried by a caregiver is unique and produces an effect separate from that of a parent rocking a child to sleep or holding an infant while stationary.
"Generally, the infant reached a plateau if you continue walking," she explained. "Infants are aware of any motion change. For example, if a mom turns. So even when the infants are sleeping, they're very keen on what parents are doing."
Kuroda reiterated that walking with an infant in your arms for five minutes continuously is crucial — then it can be followed by five to eight minutes of sitting with the child in your arms in order to "stabilize their sleep."
"The first five to eight minutes of sleep is shallow sleep," she explained. "So if you immediately place their infant down after they're asleep, you'll hit the shallow sleep, they'll wake up and you'll be unsuccessful. That's why you want to wait for that five to eight minutes after the infant falls asleep. That will increase your success rate."