That is the suggestion of a new study reported in the Aug. 21 issue of the journal Pediatric Research.
The study, which was headed by Douglas McMahon, professor of biological sciences at Vanderbilt University and an investigator at the Vanderbilt Kennedy Center for Research on Human Development, reports that exposing baby mice to constant light keeps the master biological clock in their brains from developing properly and this can have a lasting effect on their behavior.
"We are interested in the effects of light on biological clocks because they regulate our physiology extensively, and also have an important effect on our mood," McMahon said. "This study suggests that cycling the lights in NICUs may be better than constant lighting for premature babies' from the perspective of developing their internal clocks."
Every year about 14 million low-weight babies are born worldwide and are exposed to artificial lighting in hospitals.
"Today, we realize that lighting is very important in nursing facilities, but our understanding of light's effects on patients and staff is still very rudimentary," said William F. Walsh, chief of nurseries at Vanderbilt's Monroe Carrel Jr. Children's Hospital. "We need to know more. That is why studies like this are very important."
Although older facilities still use round-the-clock lighting, modern NICUs, like that at Vanderbilt, cycle their lighting in a day/night cycle and keep lighting levels as low as possible, Walsh said. Also, covers are kept over the isolets that hold the babies in an effort to duplicate the dark conditions of the womb.
The finding that exposure to constant light disrupts the developing biological clock in baby mice provides an underlying mechanism that helps explain the results of several previous clinical studies. One found that infants from neonatal units with cyclic lighting tend to begin sleeping through the night more quickly than those from un
Contact: David F. Salisbury