Babies sigh to reboot breathing: study

BETHESDA, MD. - A sleeping baby's repeated sighs not only reassure parents, the deep breaths also help reset breathing patterns, scientists say.

Healthy babies sigh every 50 to 100 breaths to reopen the tiny airways in their lungs, which are prone to collapse.

When infants sigh in their sleep, it may reset part of the brain's breathing controls.

Researchers in Switzerland and Australia wanted to know if sighs offer more than these known benefits.

David Baldwin of University Children's Hospital in Bern and his colleagues hypothesized the "deep inspirations" improve neurological control of breathing.

To find out, the team studied the heart rate, blood oxygen saturation and other breathing-related measurements of 25 healthy, one-month-old infants, as they slept in a crib or in their mother's arms.

The scientists thought sighs may reset breathing controls, like rebooting a computer by hitting a sequence of keys.

Baldwin's team found just before a sigh, an infant's breathing seems to become too regular. Sighs may add some healthy changes to the breathing patterns, they suggest.

"The response to a sigh may be different in various groups of infants at risk for inadequate control of breathing, such as premature infants, those with neurological impairments or infants at risk for [sudden infant death syndrome, or crib death]," the researchers wrote.

They suggest further studies to investigate using breathing patterns to identify infants at risk.

The study appears in this week's online edition of the Journal of Applied Physiology, published by the American Physiological Society.

Written by CBC News Online staff