Sleep matters for kids, especially when they are stressed. A new study led by researchers Jinshia Ly, Jennifer J. McGrath and Jean-Philippe Gouin from Concordia University’s Centre for Clinical Research in Health and the PERFORM Centre shows that poor sleep might explain how stress impacts health in kids.
A good night’s sleep
Getting a good night’s sleep might buffer the impact of stress on kids’ cortisol level, which is a hormone produced in the adrenal gland to regulate the body’s cardiovascular, metabolic and immune systems. While short-term exposure to cortisol prepares the body for the “fight or flight” response, long-term exposure to cortisol can put people at risk for health problems, like heart diseases, weight gain and depression.
What does it mean to have a good night’s sleep? Jinshia Ly, lead author and graduate student, explains that “sleep researchers distinguish sleep duration, or how long one spends sleeping, from sleep quality, or how well one sleeps. Sleeping throughout the night without waking up, feeling rested in the morning, and absence of sleep problems, such as nightmares, apnea and snoring, are examples of a better quality sleep.”
Examining young sleepers
For the study, which was published in Psychoneuroendocrinology, the research team recruited 220 kids aged 8 to 18 years old. The participants gave saliva samples from which their cortisol levels were measured.
The kids and their parents also answered questions about stress, sleep habits and bedtime routines. The researchers found that poorer sleep quality, regardless of how long kids spent sleeping, promoted the negative effects of stress on their cortisol levels.
Advice for parents
So what are the implications for parents, as the school year starts and stress likely increases for kids? Better sleep, combined with other healthy lifestyle behaviours, can reduce the negative consequences of stress on kids’ cortisol levels. They should sleep 8 to 9 hours each night.
“But it’s even more important that they get to bed early with regular sleep and wake times, avoid napping during the day and avoid using electronic devices before bedtime. It is also important that parents educate their kids at an early age about the importance of consistent and healthy sleep habits,” says Ly.
This solid grounding can help kids make better choices when they gain greater autonomy in setting their bedtime routines as they get older.
Funding: This study was part of the larger, ongoing Healthy Heart Project directed by Jennifer J. McGrath, associate professor from the Department of Psychology at Concordia University. This study was made possible by the Canadian Institutes of Health Research Operating Grant awarded to Jennifer J. McGrath and the Fonds de recherche du Québec – Santé bourse de formation maîtrise awarded to Jinshia Ly.
Source: Cléa Desjardins – Concordia University
Image Source: The image is adapted from the Concordia University press release
Original Research: Abstract for “Poor sleep as a pathophysiological pathway underlying the association between stressful experiences and the diurnal cortisol profile among children and adolescents” by Jinshia Ly, Jennifer J. McGrath, and Jean-Philippe Gouin in Psychoneuroendocrinology. Published online July 2015 doi:10.1016/j.psyneuen.2015.03.006
Poor sleep as a pathophysiological pathway underlying the association between stressful experiences and the diurnal cortisol profile among children and adolescents
•Poor sleep is a plausible pathophysiological pathway by which stressful experiences “get under the skin” to disrupt the diurnal cortisol profile in youth.
•The association between stressful experiences and the diurnal cortisol profile in youth was driven by the quality, not the quantity of sleep.
•The overall diurnal cortisol profile, rather than the cortisol awakening response or single sample cortisol measures, was affected by stressful experiences through sleep.
Recent evidence suggests that poor sleep is a potential pathway underlying the association between stressful experiences and the diurnal cortisol profile. However, existing findings are largely limited to adults. The present study examines whether poor sleep (duration, quality) mediates the relation between stressful experiences and the diurnal cortisol profile in children and adolescents. Children and adolescents (N = 220, Mage = 12.62) provided six saliva samples over two days to derive cortisol indices (bedtime, AUCAG, AUCTG, slopeMAX). Perceived stress, stressful life events, self-reported sleep duration, and sleep quality were measured. Using bootstrapping analyses, sleep quality mediated the relation between perceived stress and AUCTG (R2 = 0.10, F(7, 212) = 3.55, p = .001; 95% BCI[0.09, 1.15]), as well as the relation between stressful life events and AUCTG (R2 = 0.11, F(7, 212) = 3.69, p = .001; 95% BCI[0.40, 3.82]). These mediation models remained significant after adjusting for sleep duration, suggesting that poor sleep quality underlies the association between stressful experiences and the diurnal cortisol profile in children and adolescents. Longitudinal data combined with objectively-measured sleep is essential to further disentangle the complex association between sleep and stress.
“Poor sleep as a pathophysiological pathway underlying the association between stressful experiences and the diurnal cortisol profile among children and adolescents” by Jinshia Ly, Jennifer J. McGrath, and Jean-Philippe Gouin in Psychoneuroendocrinology. Published online July 2015 doi:10.1016/j.psyneuen.2015.03.006