A large study suggests that losing just one or two hours of sleep per night can increase the risk of depression and anxiety.
Researchers from the American Psychological Association looked at more than 150 studies conducted over 50 years that involved participants whose sleep was interrupted at least one night.
Participants stayed awake longer than normal or slept shorter. The team also measured the impact of sleep deprivation on mood and feelings of anxiety and depression.
The team found that all these types of sleep loss resulted in fewer positive emotions such as joy and happiness (a sign of depression) and more signs of anxiety.
The findings shed light on the lasting impact of sleep deprivation, which affects more than 40 percent of Americans.
Researchers from the American Psychological Association found that missing just one to two hours of sleep worsened symptoms of depression and anxiety
Lack of sleep can lead to obesity, memory loss, diabetes, heart disease, heightened and unstable emotions, reduced learning ability and a reduced immune response, leaving you vulnerable to disease
Dr. Cara Palmer, lead author of the study and director of the Sleep and Development Lab at Montana State University, said: 'In our largely sleep-deprived society, quantifying the effects of sleep loss on emotions is critical to promoting psychological health. '
'This study represents the most comprehensive synthesis of experimental sleep and emotion research to date and provides strong evidence that periods of prolonged wakefulness, shorter sleep duration and nighttime awakenings negatively impact human emotional functioning.'
The researchers looked at 154 studies conducted between 1966 and 2022. This included 5,715 participants aged from seven to 79 years. The average age was 23 years and the analysis included an equal number of men and women.
All participants lost sleep at least one night. In some studies, participants were kept awake for longer periods of time.
In other cases, however, they were allowed to sleep shorter than normal.
The studies also examined how emotions changed due to sleep deprivation, including self-reported mood, response to emotional stimuli, and symptoms of anxiety and depression.
The team found that all types of sleep loss measured resulted in fewer positive emotions, such as joy, happiness and contentment, which indicate depression.
Participants also experienced increased anxiety symptoms, including rapid heart rate and worry.
The researchers were surprised to find that these changes occurred even in those who lost just an hour or two of sleep in one night.
“This happened even after short periods of sleep loss, such as staying up an hour or two later than normal or after losing just a few hours of sleep,” Dr. Palmer said. 'We also found that sleep loss increased anxiety symptoms and decreased arousal in response to emotional stimuli.'
This may be because sleep deprivation causes the body to release greater amounts of the stress hormone cortisol, which activates a fight-or-flight response in the nervous system.
This response leads to physical symptoms of anxiety, including rapid breathing and high heart rate.
Additionally, not getting enough sleep changes the amount of serotonin the brain produces, which regulates mood. A deficiency of serotonin can lead to feelings of depression, including low happiness and reduced self-esteem.
The researchers noted that the age of the participants was a limitation, as the majority were young adults. They said future research should include a more diverse age group to understand how sleep deprivation affects people as they age.
A lack of sleep has been consistently linked to chronic health problems such as sleep apnea, heart disease, kidney disease, high blood pressure, diabetes, stroke, obesity and depression.
It can also lead to insomnia, where a person routinely has trouble falling asleep.
Sleep deprivation is widespread in the US.
According to 2020 data from the CDC's Behavioral Risk Factor Surveillance System, which surveyed 400,000 Americans in the U.S., the most sleep-deprived states are Hawaii, West Virginia and Kentucky.
In this dataset, sleep deprivation means less than seven hours per night.
The states with the least sleep deprivation were Colorado, Minnesota and South Dakota.
Nationally, data shows that approximately 34 percent of adults between the ages of 18 and 64 are sleep deprived (less than seven hours per night).
This drops to 26 percent when adults are over 65, but that's still over a quarter of adults not getting enough sleep.
Men are generally more likely than women to not get enough sleep, with 33.3 percent reporting sleeping less than seven hours per night, compared to 32.1 percent of women.
“Research has shown that more than 30 percent of adults and up to 90 percent of teens don't get enough sleep,” says Dr. Palmer.
'The implications of this research for individual and public health are significant in a largely sleep-deprived society.'
“Industries and sectors sensitive to sleep loss, such as first responders, pilots and truck drivers, should develop and adopt policies that prioritize sleep to reduce risks to daytime functioning and well-being.”
The research was published in the journal on Thursday Psychological Bulletin.