We all need our sleep, but not all of us are morning people. Our varied preferences for sleeping and waking periods over a 24-hour cycle—what’s known as our chronotype—reflect the diversity of human biology. However, much of society tends to be structured around ‘early birds’, which means ‘night owls’ compelled to wake early for school and work might not get as many hours of restful sleep as their peers.
The effects of chronotype on sleep problems—which include fragmented sleep, poor sleep quality and daytime sleepiness—can be particularly concerning for young children, according to Derric Eng, a Senior Research Officer at the A*STAR Institute for Human Development and Potential (A*STAR IHDP).
“Evening chronotype in children isn’t only linked to increased sleep problems, but to greater socioemotional problems later in life, such as difficulties with handling feelings and getting along with others,” said Eng.
Alongside researchers from institutes in Singapore, Finland, Canada and the Netherlands, Eng and A*STAR IHDP colleagues including Principal Scientist Shirong Cai set out to investigate the long- term associations between chronotype, sleep problems and socioemotional outcomes in children from the ages of four to seven.
Previous studies have often focused on investigating the individual relationships between each factor within the same timepoint during childhood. The team drew on the ongoing Growing Up in Singapore Towards healthy Outcomes (GUSTO) study, which provided more than a decade’s worth of detailed health observations on over 1,200 pregnant Singaporean women and their children. This allowed the team to observe the pathway linking all three factors together
over time as the same children grew up.
The team found that sleep duration did not account for the association between chronotype and socioemotional problems at primary school age. Instead, quality of sleep mattered more: negative socioemotional outcomes were more strongly associated with increased sleep disturbances seen in children with greater evening preferences.
“It was fascinating to confirm our hypothesis that early sleep problems may be an important factor linking chronotype with later socioemotional problems,” said Eng.
The team’s findings aligned with previous studies which implied that socioemotional problems faced by ‘evening’ children are due less to their chronotype, but more to social jetlag: the misalignment between a person’s biological clock and social schedule.
“Our findings imply that children with evening preferences are not necessarily ‘doomed’ to develop socioemotional problems,” Cai said. “However, sleep problems may be a more appropriate target for early intervention than sleep duration.”
While the current study relied on reports by caregivers, Eng suggested that future studies could use more objective measures of sleep. The team may also extend their work to adolescence, being another important period linked to profound changes in sleep habits and socioemotional development.
The A*STAR-affiliated researchers contributing to this research are from the A*STAR Institute for Human Development and Potential (A*STAR IHDP).
