Physical illnesses such as cold, flu, and gastroenteritis were more common among healthy adolescents who received less sleep at night, reported investigators at Bradley Hospital of Brown University in Providence, R.I.
The study was led by Kathryn Orzech, Ph.D., of the Sleep Research Laboratory. Orzech and her team compared three outcomes between longer and shorter sleepers: number of illness bouts, illness duration and school absences related to illness.
The team found that bouts of illness declined with longer sleep for both male and female high school students.
Longer sleep was also generally protective against school absences that students attributed to illness.
Researchers also found that males reported fewer illness bouts than females, even with similar sleep durations.
Orzech’s team analyzed total sleep time in teens for six-day windows both before and after a reported illness and found a trend in the data toward shorter sleep before illness vs. wellness.
Due to the difficulty of finding teens whose illnesses were spaced in such a way to be statistically analyzed, Orzech also conducted qualitative analysis, examining individual interview data for two short-sleeping males who reported very different illness profiles.
Irregular sleep timing — very little sleep during the week and “catching up” on sleep during the weekend — and a preference for scheduling work and social time later in the evening hours, were found to influence differences in illness outcomes.
“Some news reaches the general public about the long-term consequences of sleep deprivation, such as the links between less sleep and weight gain,” said Orzech.
“However, most of the studies of sleep and health have been done under laboratory conditions that cannot replicate the complexities of life in the real world.
“Our study looked at rigorously collected sleep and illness data among adolescents who were living their normal lives and going to school across a school term.”
“We showed that there are short-term outcomes, like more acute illness among shorter-sleeping adolescents, that don’t require waiting months, years or decades to show up,” Orzech continued.
“Yes, poor sleep is linked to increased cardiovascular disease, to high cholesterol, to obesity, to depression, etc., but for a teenager, staying healthy for the dance next week, or the game on Thursday, may be more important.
“The message from this study is clear: Sleep more, and more regularly, get sick less.”