When my girls were babies, sleep machines were all the rage among parents hoping to help their wee ones get some shut eye. Some emit white noise, while others play nature sounds. And all are aimed at masking other sounds and helping babies fall asleep faster. But a new study released today has found that those machines may be so loud that the noise is actually damaging to a baby's ears.

The study published online in the journal Pediatrics tested several different sound machines and found that all 14 machines tested exceeded 50 decibels, when measured within a distance of one yard or closer. All but one machine exceeded this level even from a distance of about 2.2 yards.

This is alarming considering that most parents who use these machines place them in close proximity to a baby's crib — often less than one foot away. And these noise machines are often left on all night to promote a good night's sleep. At this distance, three of the machines exceeded 85 decibels — the workplace safety limit for adults exposed to noise over an eight-hour shift.  

“These machines are capable of delivering noise that we think is unsafe for full-grown adults in mines,” said Dr. Blake Papsin, the lead researcher of the study and the chief otolaryngologist (an ear, nose and throat doctor) at the Hospital for Sick Children in Toronto. 

Papsin said he got the idea for the study after visiting an infant in the hospital whose parents had brought in a noise machine so the baby could sleep. Papsin said that the noise in the room was so loud that he could not hear or talk to the baby's parents.  

Papsin also noted that he isn't telling parents not to use the machines, but to be aware that there is a potential risk to a baby's hearing. The best bet is to place the machine as far away from your baby's crib as possible and make sure that the setting is on the lowest volume. Also, don't leave the sleep machine on all night; rather, turn it off after a few hours or once your baby has fallen asleep.

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