Study reveals effects of light on newborns

By HSC Staff Writer • Published: May 8th, 2007
Category: Health in a Heartbeat

Talk of mice and clocks is usually reserved for nursery rhyme readings of Hickory-dickory-dock. But now there’s a scientific angle.

New research in the journal Pediatric Research shows that exposing baby mice to constant light plays havoc with their master biological clocks.

Vanderbilt University scientists say their study suggests that keeping the lights on around the clock in neonatal intensive care units may interfere with the development of premature babies’ biological clocks.

Yearly, about fourteen-million low-weight babies are born worldwide and are exposed to artificial lighting in hospitals.

The brain’s biological clock governs numerous body functions that are synchronized with the normal, twenty-four-hour day-night cycle… including body temperature, hormone secretion, mood and blood pressure changes.

Newborn mice provide a good model for studying premature infants because baby mice are born at an earlier stage of development than humans… a stage resembling that of premature babies.

Vanderbilt University researchers studied two groups of newborn mice over the first three weeks of life… one exposed to constant light and the second group exposed to a normal cycle of twelve hours of light and twelve hours of darkness.

The biological clocks of the baby mice in a normal light cycle quickly became synchronized. In contrast, the clock neurons of the constant-light mice were unable to maintain coherent rhythms.

Researchers say cycling the lights in neonatal I-C-U’s may be better than constant lighting for premature babies from the perspective of developing their internal clocks.