Washington: Scientists have finally confirmed what our grandmas have been preaching over the years – babies do really wake up taller right after their sleep.
Findings from the first study of its kind measuring the link between daily growth and sleep confirm that infants gain height during sleep, depending on the total hours slept and number of sleep bouts.
"Little is known about the biology of growth spurts. Our data opens the window to further scientific study of the mechanisms and pathways that underlie saltatory growth," said lead author Michelle Lampl, from the department of anthropology at Emory University in Atlanta, Georgia.
Researchers have found that longer sleep bouts in both girls and boys predicted an increase in weight and body-fat composition tied to an increase in length.
This means that not only does sleep predict a growth spurt in length, but it also predicts an increase in weight and abdominal fat, implying an anabolic growth process.
It has also emerged that boys exhibited more sleep bouts and shorter sleep bouts than girls. But, neither the sex of the infant nor breastfeeding had significant effects on total daily sleep time.
However, breastfeeding as opposed to formula feeding was associated with more and shorter sleep bouts.
The findings are based on data of 23 infants recorded in real time over a four- to 17-month span.
During this time, mothers kept daily diaries of sleep onset and awakening, noted whether babies were breastfeeding, formula feeding, or both and whether their infant showed signs of illness, such as vomiting, diarrhea, fever or rash.