Lead author Melissa Sturge-Apple of the University of Rochester in New York and colleagues said although the effects of stress have been well documented in children and linked to a variety of diseases in adults, this is one of the first studies to look specifically at stress and parenting.
"Stress gets under your skin," Sturge-Apple said in a statement. "Stress is not just in our heads, it's in our bodies."
Fred Rogosch, research director at the University of Rochester's Mt. Hope Family Center and a study author, measured physiological stress response in real time by using a novel wireless electrocardiograph monitor developed by University of Rochester engineers Zeljko Ignjatovic and Wendi Heinzelman.
The device allowed the team to analyze subtle changes in participants' heart rhythms as they were happening. The study involved 153 mothers and their 17-to-19-month-old children in individual 2-hour sessions.
The study, published in Development and Psychopathology, said although the popular image of depression is of someone who is listless and sad, the study confirms what clinicians have long observed -- that depression in mothers sometimes is linked to harsh, highly reactive parenting, not subdued mothering.
By contrast, study participants who struggled with poverty and lived in high-crime neighborhoods exhibited underactive stress response systems -- their heart rates patterns began lower and rose little during their child's distress, the study found.