People's emotional functioning suffers when their sleep is disrupted, study finds  

Peer-reviewed – Meta-analysis - People  

Losing sleep does more than just make us tired - it can undermine our emotional functioning, making us less positive and increasing our risk for anxiety symptoms, according to a new study.  

"Our society is frequently sleep deprived, so understanding the effects of this on our emotions is critical to promoting good psychological health," said lead author Dr Jo Bower of the University of East Anglia.   

"This study represents the most comprehensive analysis of experimental sleep and emotion research to date, and provides strong evidence that sleeping less, being awake for longer, and waking during the night can adversely influence human emotional functioning."   

The study was published in the journal Psychological Bulletin by the American Psychological Association and synthesised more than 50 years of research on sleep deprivation and mood.   

Dr Bower and her colleagues, including the other lead author, Dr Cara Palmer, of Montana State University, analysed data from 154 studies spanning five decades, with 5,715 total participants.  

In all those studies, researchers disrupted participants' sleep for one or more nights. In some experiments, participants were kept awake for an extended period. In others, they were allowed a shorter-than-typical amount of sleep, and in others they were periodically awakened throughout the night.  

Each study also measured at least one emotion-related variable after the sleep manipulation, such as participants' self-reported mood, their response to emotional stimuli, and measures of depression and anxiety symptoms.   

Overall, the researchers found that all three types of sleep loss resulted in fewer positive emotions such as joy, happiness and contentment among participants, as well as increased anxiety symptoms such as a rapid heart rate and increased worrying.    

"Even small amounts of sleep loss, like staying up for an extra hour or two had an impact on our emotional functioning," Dr Bower said.  "We also found that sleep loss increased anxiety symptoms, and reduced arousal in response to emotional stimuli."   

Findings for symptoms of depression were smaller and less consistent. The findings were also more mixed for negative emotions such as sadness, worry and stress.    

One limitation to the study is the majority of participants were young adults – the average age was 23.   

Future research should include a more diverse age sample to better understand how sleep deprivation affects people at different ages, according to the researchers.   

Dr Bower suggests "it would also be interesting to examine how emotional functioning recovers after sleep is restored".   

Other directions for future research could include examining the effects of multiple nights of sleep loss, looking at individual differences to find out why some people may be more vulnerable than others to the effects of sleep loss, and examining the effects of sleep loss across different cultures, as most of the research in the current study was conducted in the United States and Europe. 

Dr Bower said: "Recent, worldwide research has shown that only 15 per cent of adults get the recommended amount of sleep for at least five nights per week. This has considerable implications for individual and public health research, including in sectors prone to sleep loss."  

Sleep Loss and Emotion: A Systematic Review and Meta-analysis of Over Fifty Years of Experimental Research, by Cara Alexis Palmer, PhD, Montana State University; Joanne L. Bower, PhD, University of East Anglia; Kit W. Cho, PhD, University of Houston Downtown; Michelle A. Clementi, PhD, University of Colorado - Anschutz Medical Campus; Simon Lau, PhD, and Candice A. Alfano, PhD, University of Houston; and Benjamin Oosterhoff, PhD, Meadows Mental Health Institute, is published in the Psychological Bulletin.