Sleep deprivation impairs teamwork, productivity

Sleep deprivation of 21 hours or more impairs teamwork by reducing cooperative behaviors. The team’s perception is also skewed the longer they go without sleep, leading them to believe they are more effective than they are, according to a study published in the January issue of Sleep Research Society. Results were also published online in September 2025.

A team of researchers, including Ellyse Greer, from the Behavior-Brain-Body Research Centre, University of South Australia, studied the effects of sleep deprivation on 22 participants, placed into teams of four, for three days and two nights. Sleep deprivation hours totaled 62 hours. Teamwork was measured at hours 6, 15, 21, 36 and 56.

The primary measure of performance and cooperation was assessed using the COHESION (Capturing Objective Human Econometric Social Interactions in Organizations and Networks) task, a prototype team performance task developed for NASA.

During the timed test, participants earn points by dragging resources into a target zone. Invisible barriers are randomly assigned at random points in time, and a point is deducted for every time a resource hits a barrier.

Each team member is assigned four barriers only they can see. A team member can help the group by revealing a barrier, but this requires them to pause for several seconds. Although this increases the individual’s ability to score points for the group, it impairs an individual’s ability to score points for themselves.

Team performance score was the sum of all points scored. Individual performance was scored using the number of points each individual scored for themselves.

Cooperation is defined as the percentage of time players engaged in barrier-reveal behaviors.

Noticeable declines in cooperative behavior appeared at hour 21. Major productivity deficits appeared by hour 36, when team members were no longer able to engage effectively with their teams.

After each COHESION session, team members rated teamwork quality using a 10-point scale. Self-reported alertness was measured using the Karolinska Sleepiness Scale (KSS).

Teams believed they were doing better than they were, with a perceived team cohesion score of 10.44 points. The scores were much lower. The team performance score was 2.58 points, the equality of cooperation score was 5.77 and the equality of productivity score was 4.07.

The findings highlight a critical gap between perceived and actual team effectiveness under conditions of extreme fatigue. As sleep loss increased, individuals became more focused on personal task completion and less willing to sacrifice time to support teammates, undermining collective outcomes. This disconnect suggests that fatigued teams may lack awareness of declining cooperation, increasing risk in high-stakes environments.

“Enduring periods of high fatigue are inevitable in 24/7 operations,” Greer and her colleagues write in the study. “These results could help inform other scenarios of distributed teaming, for example, collocated teams with little contact or disaggregated teams who need to rapidly geographically disperse.”

Sleep deprivation doesn’t just impact teamwork and productivity; it can be deadly. Drowsy driving causes approximately 6,000 fatal crashes every year. Approximately two-thirds of Americans don’t get the recommended seven or more hours of sleep every night. This also leads to a greater risk of health problems, including cancer, heart disease and diabetes.

“The findings from this study have serious implications for distributed teams that work in fatiguing safety-critical industries, such as aviation, emergency services, transport, healthcare and defense,” Greer writes in the study.