Extroverts are more vulnerable to the effects of sleep deprivation after they've had lots of social activity than after they've been alone, researchers have found.
The new study included 23 extroverts (outgoing, unreserved folks) and 25 introverts (reserved, shy types), aged 18 to 39, who were randomly assigned to either a "socially enriched group" or a "socially impoverished group".
Those in the socially enriched group spent 12 hours (10am to 10pm) interacting with research technicians, playing card and board games, doing puzzles, having group discussions and watching movies. Those in the other group did similar activities by themselves in private rooms.
The introverts in both groups showed no differences in vulnerability to subsequent sleep deprivation. But the extroverts in the social activity group were more likely to experience sleep problems than those in the social isolation group, according to lead author Tracy L. Rupp, a research psychologist at the Center for Military Psychiatry and Neuroscience at the Walter Reed Army Institute of Research in Silver Spring, Md.
"The ability of introverts to resist sleep loss was relatively unaffected by the social environment. Overall, the present results might also be interpreted more generally to suggest that waking experiences, along with their interaction with individual characteristics, influence vulnerability to subsequent sleep loss," the study authors said in a news release from the American Academy of Sleep Medicine.
The authors also explained that because social interactions may lead to fatigue in brain regions that control attention and alertness, high levels of social stimulation may boost the need for sleep. However, some people may be resistant to sleep loss, a trait that could be linked to genetics. In particular, people who tend to be introverts may have an increased resistance to sleep deprivation, they noted.
The study findings are published in the journal Sleep.
The findings may have significance for occupations that require workers to remain alert during extended periods of time. This ability may be dependent on certain personality traits, the researchers pointed out.