A leader can have the right knowledge, the right experience and the right information — yet still make a poor decision.
Why?
Because effective decision-making depends on more than what a leader knows.
It also depends on the brain’s capacity to process information, evaluate alternatives, regulate emotions, and anticipate consequences.
And that capacity is influenced by sleep.
The Brain Behind Every Leadership Decision
Leadership involves making decisions, often with incomplete information and under significant pressure.
Whether evaluating an investment, resolving a conflict, or responding to an unexpected crisis, leaders rely on cognitive functions such as attention, working memory, reasoning, and impulse control.
These abilities depend on coordinated activity across several brain networks, including those involving the prefrontal cortex.
Insufficient sleep can disrupt cognitive functioning, making it more difficult to maintain attention, process complex information, and respond effectively to changing circumstances.
A leader may still be able to attend meetings, review reports, and participate in discussions.
But being awake and functioning is not necessarily the same as operating at optimal cognitive capacity.
What Research Tells Us
In a 2020 experimental study, Salfi and colleagues investigated how sleep deprivation affected impulsivity and decision-making [1].
Their findings showed that repeated partial sleep deprivation increased impulsive decision-making and risk-taking.
One particularly interesting observation was that individuals who were normally cautious appeared especially susceptible to these changes.
This suggests that the decision-making style we associate with an experienced, careful leader may not remain entirely stable under conditions of insufficient sleep.
A separate scoping review published in 2025 examined 25 studies involving 2,276 participants [2].
The review found that many studies reported impaired decision-making following sleep deprivation, although the effects differed across tasks and individuals.
Together, these findings reinforce an important distinction:
Having the capability to make good decisions does not guarantee having the cognitive capacity to exercise that capability consistently.
Why Sleep-Deprived Leaders May Not Recognize the Problem
One challenge with insufficient sleep is that individuals may continue performing familiar tasks despite reductions in certain cognitive abilities.
A leader can remain articulate, confident, and engaged while experiencing difficulties with sustained attention or complex reasoning.
This matters because confidence and cognitive performance are not always the same.
The ability to recognize one’s own performance limitations may also be affected under certain conditions of sleep loss.
As a result, a leader may underestimate how fatigue is influencing judgment.
The concern is not that every decision made after a poor night’s sleep will be wrong.
It is that insufficient sleep can increase vulnerability to errors, particularly when decisions require sustained concentration, careful evaluation, or adaptation to changing information.
Decision-Making Is Also Emotional
We often think of decision-making as a purely rational process.
In reality, emotions influence how we interpret information, assess threats, and respond to uncertainty.
Sleep plays an important role in emotional regulation.
Research discussed by Stanford Medicine highlights the bidirectional relationship between sleep and mental health, including the influence of sleep disruption on emotional stability and stress vulnerability [3].
When leaders are tired, heightened emotional reactivity or reduced tolerance for frustration may influence how they respond to disagreement, unexpected setbacks, or challenging conversations.
For example, a leader might become less patient when considering alternative viewpoints or respond more defensively to criticism.
These are potential consequences of impaired emotional regulation, not inevitable outcomes for every sleep-deprived individual.
Nevertheless, they demonstrate why decision-making cannot be separated entirely from emotional functioning.
Capability × Capacity: The Missing Equation
Organizations spend considerable resources developing leadership capability.
Executives attend strategy programmes, decision-making workshops, leadership development courses, and executive coaching sessions.
These investments build valuable knowledge and skills.
But there is another variable.
Leadership performance depends not only on capability, but also on the capacity to use that capability effectively.
Capability represents what a leader knows and can do.
Capacity reflects the cognitive, emotional, and physiological resources available to put those abilities into practice.
A highly capable leader operating with reduced capacity may not consistently perform at their best.
This is why sleep and recovery deserve a place in conversations about leadership effectiveness.
They help support the brain functions that allow experience, knowledge, and expertise to translate into sound judgment.
Better Decisions Begin Before the Meeting
Organizations frequently seek to improve decision-making through better data, more sophisticated analytics, and structured frameworks.
All are important.
But decision quality also depends on the condition of the person interpreting the information.
A practical approach to supporting leadership decision-making should therefore include adequate sleep, opportunities for recovery, and awareness of fatigue during periods of sustained pressure.
For particularly consequential decisions, leaders may benefit from avoiding unnecessary sleep restriction, seeking independent perspectives, and allowing adequate time for deliberation whenever circumstances permit.
These practices cannot guarantee good decisions.
They can, however, help reduce avoidable conditions that may compromise judgment.
The Question Every Leader Should Ask
Experience matters.
Knowledge matters.
Good information matters.
But none operates independently of the brain responsible for using them.
Sleep is not a substitute for leadership competence.
It helps protect the cognitive capacity required to exercise that competence.
Before your next important decision, consider asking yourself:
Am I making this decision with the full benefit of my experience — or with a brain that has not sufficiently recovered?
Because better leadership decisions may begin long before entering the boardroom.
They may begin the night before.
References
[1] Salfi, F., et al. (2020). Effects of Total and Partial Sleep Deprivation on Reflection Impulsivity and Risk-Taking in Deliberative Decision-Making. https://pmc.ncbi.nlm.nih.gov/articles/PMC7261660/
[2] Agyapong-Opoku, F., et al. (2025). Examining the Effects of Sleep Deprivation on Decision-Making: A Scoping Review. https://pmc.ncbi.nlm.nih.gov/articles/PMC12189852/
[3] Stanford Medicine. (2025). How Sleep Affects Mental Health (and Vice Versa): What the Science Says. https://med.stanford.edu/news/insights/2025/08/sleep-mental-health-connection-what-science-says.html