The future is sleep-deprived

Losing sleep is actually something to lose sleep about. It doesn’t just make us tired – it can increase anxiety, degrade mood and altogether undermine our emotional functioning, according to a new study. The study, published in the journal Psychological Bulletin, synthesized more than 50 years of research on sleep deprivation and mood.

What the researchers say: “Emotions govern virtually every aspect of our daily lives, and depriving ourselves of sleep seems to be a sure way to elect a terrible governor, or president. Our findings confirm that even when sleep is only mildly deficient, there are measurable negative changes in how we react to everyday events,” the lead author said.

“In our increasingly sleep-deprived society, quantifying the effects of sleep loss on emotion is critical for promoting psychological health,” added the lead researcher. “This study represents the most comprehensive synthesis of experimental sleep and emotion research to date, and provides strong evidence that periods of extended wakefulness, shortened sleep duration, and nighttime awakenings adversely influence human emotional functioning.”

The team analyzed 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.  

“This occurred even after short periods of sleep loss, like staying up an hour or two later than usual or after losing just a few hours of sleep,” the researchers said. “We also found that sleep loss increased anxiety symptoms and blunted arousal in response to emotional stimuli.”

“Research has found that more than 30% of adults and up to 90% of teens don’t get enough sleep,” they added. “The implications of this research for individual and public health are considerable in a largely sleep-deprived society. Industries and sectors prone to sleep loss, such as first responders, pilots, and truck drivers, should develop and adopt policies that prioritize sleep to mitigate against the risks to daytime function and well-being.”

So, what? The need for “adequate” sleep is part of human design specs, although “adequate” differs from person to person depending on their age.

Generally, we humans are designed to go to sleep when it gets dark and awake with the dawn. However, the answer to the question “why do humans (like every other mammal) need sleep? has eluded scientists up to now.

A separate study published this week may have the answer. “The brain is like a biological computer,” its lead author said. “Memory and experience during waking change the code bit by bit, slowly pulling the larger system away from an ideal state. The central purpose of sleep is to restore an optimal computational state.” Rather like rebooting your computer or smartphone.

How much sleep do we need? According to recent research, adults below the age of 60 require 6-7 hours sleep per night, whereas those over 60 need about 6 hours.