Young adults have a natural sleep requirement of about 9 hours a day on average, older adults 7.5 hours. Many people in western societies, however, get considerably less sleep. According to studies, about one-third of the persons surveyed in several industrial countries reported too little sleep.

Not enough sleep leads to riskier decision-making and identified a further critical consequence of a chronic lack of sleep: increased risk-seeking. If the students slept only 5 hours a night for a week, they displayed clearly riskier behavior in comparison with a normal sleep duration of about 8 hours.

While a single sleepless night had no effect on risk-seeking, 11 of 14 of the subjects behaved significantly and increasingly riskier as the week of a reduced sleep duration went on. The students assess their risk-taking behavior to be the same as under regular sleep conditions.

“We therefore do not notice ourselves that we are acting riskier when suffering from a lack of sleep,” emphasizes Christian Baumann, professor of neurology and the head of the Clinical Research Priority Programs (CRPP) “Sleep and Health” at UZH.

The researchers have proven that a low depth of sleep in the right prefrontal cortex is directly connected with higher risk-seeking behavior. This part of the cerebral cortex has already been associated with risk-taking behavior in earlier studies.

“We assume that behavioral changes occur for anatomical-functional reasons to some extent as a result of the right prefrontal cortex not being able to recover properly due to a chronic lack of sleep,” Baumann says.