A Norwegian study has found that toddlers who spend the longest time in day care (eight to nine hours) have higher levels of the stress hormone cortisol during the day, compared to days they spend at home. Children who go to day care seven hours per day or less show no increase.
Based on the findings, it appears that toddlers who have the longest day-care days must mobilize extra emotional resources to handle the challenges of being there full-time, and/or the long separation from their parents. Higher levels of stress may trigger emotional reactions in young children which may require extra patience and understanding from their caregivers and parents.
Several international studies have previously shown that young children show increased levels of cortisol on their full-day child care days, while their levels at home remain steady or decline. This has led to speculation that childcare settings pose challenges for young children — from being in a large group, managing interactions with other children, to being away from their parents.
There are no studies examining whether child care stress can have negative effects in the long term, so it remains unknown.
For the study, researchers at three Norwegian regional centers for child and adolescent mental health — the Norwegian University of Science and Technology’s RKBU Central Norway, RBUP East & South, and the University of Oslo — measured cortisol levels in 112 toddlers from 85 different child-care centers in six municipalities, approximately five months after they started attending. The children’s cortisol levels were measured around 10:00 a.m. and 3:00 p.m.
The results show that Norwegian toddlers with the longest day-care days (eight to nine hours) had an increase in the stress hormone cortisol on their child-care days, with lower levels on their days at home. Children who were in childcare seven hours per day or less showed no increase.
The findings indicate a correlation between the amount of time children spend in childcare and their stress levels. This is particularly relevant In Norway, as most one- and two-year olds here spend more than 40 hours per week in day care.
The researchers stress that the study has several limitations and that the findings therefore should be interpreted with caution. They say that the study should be followed up by a larger study with a broader range of participants, to determine whether the results can be replicated and to have the opportunity to examine any differences between different groups of children.