19 Nov Less Sleep: More Illness in Adolescents
MedicalResesarch.com: What are the main findings of the study?
Dr. Orzech: We found that acute illnesses, such as colds, flu, and gastroenteritis were more common among healthy adolescents with shorter sleep. Specifically, our main analysis found that reported bouts of illness (analyzed on a bouts-of-illness-per-interview basis) 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. There were sex differences, with males reporting fewer illness bouts than females, even with similar sleep durations. This is consistent with another recent study that showed a lower impact of shorter sleep on male adolescents (in that case the outcome was male adiposity), but more research is needed.
We also conducted a secondary analysis to examine total sleep time in matched 6-day windows before illness and before wellness in the same adolescents. Although the number of participants who met our strict criteria for a healthy 6-day window before illness or wellness was only 18 (I was amazed at how difficult it was to find adolescents who reported being completely well for 6 consecutive days), we were able to see a trend in the data toward shorter sleep before illness vs. wellness. Because of the difficulty in comparing sleep before illness vs. wellness, we conducted a qualitative analysis as well, choosing two 17 year old males who were both shorter sleepers, but who reported very different illness profiles – 0 days of illness vs. 35 days of illness across the school term. An in-depth look at notes made by interviewers allowed us to create brief case studies to illustrate that not all shorter sleepers are alike. More irregular sleep timing across weeknights and weekends (much shorter sleep during the week and longer sleep times on the weekend), and a preference for scheduling work and social time later in the evening hours may both contribute to differences in illness outcomes.
MedicalResesarch.com: Were any of the findings unexpected?
Dr. Orzech: The findings were consistent with other published literature about sleep and health (i.e., that shorter or more interrupted sleep has negative health consequences) but our study is one of the first to support this relationship with short-term illness outcomes like colds, flu, etc.
MedicalResesarch.com: What should clinicians and patients take away from your report?
Dr. Orzech: For clinicians: Sleep matters for health! We drew on a unique data set of rigorously collected sleep timing data and frequent interviews about illness and other topics. Using these data, we were able to show relationships between shorter sleep timing and more acute illness, bolstering the widely held idea that better sleep means better health – not just in the long term but in day-to-day life as well.
For patients: Sleep matters for health! If you sleep more, and more regularly, you may get sick less.
Especially for Teens: you really do need your sleep even though society tells you the opposite! If you are falling asleep everywhere, like Bob (one of the case study participants) reports, that is not normal teenage sleep, that is your body trying to tell you that you need more sleep to function.
MedicalResesarch.com: What recommendations do you have for future research as a result of this study?
Dr. Orzech: More research is needed on the relationship between sleep and health “in the wild” – i.e., outside of the laboratory. There are many biological and social factors that contribute to both sleep and health, and these factors vary across the lifespan and across cultures, but have rarely been explored. More research should also be done on gender differences in sleep and health, as our findings pointed to a lesser impact of short sleep on health for male adolescents and it is unclear if this was an effect of male gender or some characteristic shared by males in our particular sample.