The solution is a magic couple numbers — five and eight — according to Japanese researchers who conducted experiments with 21 mothers trying to lull their little ones to sleep.
Here’s how it works: Walk your baby for at least five minutes without any sudden movements, and then the little one will be calm, if not asleep, according to research. Then sit and hold the baby for another eight minutes before making a gentle crib transfer.
Putting the sleeping baby to bed without sitting quietly for eight minutes was disappointing, according to study author Dr. Kumi Kuroda, team leader of the social behavior unit of the RIKEN Center for Brain Science in Saitama (Japan).
“Although we didn’t anticipate it, the key parameter for putting babies to sleep well was (delay) from sleep onset,” Kuroda said in a statement.
“I have raised four children and conducted these experiments, but even I could not have predicted the key results of this study until the statistical data came out,” added Kuroda.
“Kids are different and (some) don’t all respond to this system,” said Shu, who was not involved in the research.
Shu said in an email.
Heart rate data key
Sitting the crying baby down didn’t work, according to the study; the monitors showed that the baby’s heart rate had increased the behavior continued. Not surprisingly, putting the crying baby directly into the crib didn’t work either.
Movement alone calmed the children, according to the study. In five minutes, everything Among the children carried by mothers who were walking, crying stopped, heart rates slowed and 46% of children were asleep. According to the study, 18% more children fell asleep within minutes.
However, the five-minute walk only meant sleep for crying babies. “Surprisingly, this effect was not present when the babies were calm beforehand,” Kuroda said.
The researchers saw similar results when parents pushed their babies in strollers, but the impacts were not as strong.
Now even more difficult: to keep sleeping children awake. A third of the babies in the study woke up immediately after lying down, albeit gently. But it wasn’t the touch of the bed on a child’s body that woke him up, according to the study. Instead, the monitors showed the baby’s heart rate response increased when the baby was released from the mother’s body.
However, when the babies were held for an extra eight minutes, they fell into more stable sleep, not waking up when separated from their mothers, the researchers found.
Why does carry work?
Human babies, like other mammals, respond to what’s called the “transportation response,” an innate reaction seen in species whose babies are too immature at birth to walk or fend for themselves.
You see it all the time in nature videos: mother lions, tigers and other wild cats, even their domestic cousins, carry their cubs by the neck. So are dogs, mice and rats. Great apes, monkeys, and other primates carry their babies on their backs, where the babies rest and cling, as do opossums and giant anteaters. Marsupials such as kangaroos, koalas and wallabies have specialized pouches to accommodate their babies as they grow.
Unfortunately, it seems that humans are not as lucky as other mammalian mothers, and have to carry their young for longer to get the same answer. There is another thing that separates people — The need for human babies to learn to sleep on their own.
“Fully holding or rocking the baby to sleep creates a routine that the baby will learn to expect,” Shu said. “When baby wakes up in the middle of the night in a light sleep (as we all do), you may want to repeat the routine.”
And don’t be too quick to soothe a baby older than 3 months when he wakes up, the AAP advises. Like adults, the baby can move and fuss well and fall asleep.