Want to optimise your work performance? Sleep more.

Outperform everyone… by going to bed

One of the things that used to grind my gears when I worked as a lawyer in private practice was the people who bragged about how late they were working in the office. For those brave enough to leave the office at 7pm, they’d often be on the receiving end of enraging comments like, “Half day today?” (Heaven forbid someone had a life outside of working until 2am).

But beyond the absurdity of these comments, what annoyed me wasn’t that people got some weird gratification from how many hours they billed (each to their own). Rather, it was the fact that, in order to work until 2am, they were sacrificing the single most important thing for their health: sleep.

It seems deranged that, with all the literature available on the benefits of sleep, I even need to write an article on why it’s important. But after attending a conference last week and listening to a lawyer go on about how busy he was and that he was consistently sleeping at 4am, I feel compelled.

---

Sleep deprivation could literally kill you

The first reason to take sleep seriously is because not getting enough of it may, quite literally, kill you. I wish I were being dramatic. It may not happen overnight, but chronic sleep deprivation has been linked to serious long-term health issues, including a significantly higher risk of developing dementia.

Consider Margaret Thatcher and Ronald Reagan. Both famously prided themselves on getting by with just four hours of sleep a night. Both later developed Alzheimer’s disease.

The reason why inadequate sleep may increase the risk of dementia was explored in a Harvard Health study. The study attributed the cause to the build-up of a protein called beta amyloid. This protein, when it accumulates, clumps together to form plaques that are found in the brains of Alzheimer’s patients.

The study explained that during the day, we all produce some beta amyloid in the brain. However, when we sleep, particularly during the REM cycle, the brain activates a cleansing process that drains out toxins like beta amyloid. So the theory goes: if you don't get enough sleep, your brain doesn’t have enough time to flush out these substances. Over the years, that build-up can lead to cognitive decline.

The good news is that you can reduce this risk simply by getting enough sleep.

---

Not enough sleep hampers your day-to-day work performance

For the high achievers who aren’t swayed by long-term health risks, consider this: lack of sleep destroys day-to-day performance. People consistently underestimate just how much sleep affects their ability to think, work and lead. The truth is, sleep is the ultimate cognitive enhancer and, without it, you’re sabotaging your own output.

• Reduced memory and learning: Sleep helps consolidate information. Think of it like hitting “save” on everything you learned that day. Experiments have shown that even one night without sleep can reduce your ability to learn new facts by up to 40%. If your job requires you to pick things up quickly, and most do, running on sleep debt puts you at a massive disadvantage.

• Weakened concentration: Lack of sleep messes with your attention span and working memory. In simple terms, it becomes harder to focus and easier to make mistakes. Ever been told to work on your attention to detail? Try sleeping more first.

• Poor decision-making: Sleep-deprived people are more impulsive and more likely to take uncalculated risks because their brains become less sensitive to outcomes, good or bad. This is particularly alarming in high-stakes fields. In industries like aviation and emergency response, critical decisions are actively discouraged when someone’s underslept, as judgement becomes distorted and risk perception goes out the window.

• Reduced creativity and problem-solving: REM sleep boosts the brain’s ability to connect unrelated ideas and draw insights, a key ingredient in creative thinking. Without it, your brain struggles to make strategic links or spot big-picture patterns. A tired manager will literally have fewer insights, less clarity and poorer recall of key facts when making decisions.

In short: sacrificing sleep won’t give you a competitive edge.

---

The link between sleep and career advancement

It might sound unlikely, but getting quality sleep can actually improve your chances of being promoted. If you’ve followed any of my articles, you’ll know I’ve often said that it’s not always the smartest people who rise through the ranks. More often, it’s the charismatic captains of crisis — the ones who stay calm under pressure, read a room well and get people onside. To get promoted, you need to show emotional steadiness, warmth, likeability, empathy and the ability to work well with others. Sleep, or rather, the lack of it, erodes all of these traits.

When you’re sleep-deprived, you’re more irritable and emotionally volatile. In a workplace context, that might look like snapping at a colleague over a minor mistake or feeling overwhelmed by small setbacks. To those in charge of promotions, this signals poor emotional control and a lack of resilience, traits that don’t scream leadership potential.

Sleep is often referred to as “overnight therapy” because REM sleep helps the brain process emotional experiences and reset our psychological balance. Without enough of it, emotional reactivity spikes. The brain’s emotional centre becomes more active, while the rational part that keeps us in check quietens down. One study found that sleep-deprived people are up to 60% more reactive to emotional triggers. As Arianna Huffington put it, “when I’m exhausted, I’m the worst version of myself. I’m more reactive. I’m less empathetic. I’m less creative.” In a professional setting, this shift can make a normally composed and charismatic person appear erratic, cold or unpredictable, which is not exactly what you want in a leader.

---

The people at the top are sleeping and so should you

The last thing I’ll say about sleep is this: I genuinely don’t know where this bizarre badge of honour for not sleeping came from. From somewhere, office workers (me included, by the way) bought into the myth that high achievers (CEOs, entrepreneurs, top execs) operate on four hours a night and still manage to perform. But it’s a myth. Modern research and high performers themselves are now debunking it.

The truth is, even the most successful people are human. And humans need sleep. In fact, the higher the stakes, the more essential rest becomes for leadership, creativity, decision-making and basic emotional function.

So instead of idolising the guy in your office who brags about staying up till 3am formatting due diligence reports, pay attention to people who actually perform at the top. Jeff Bezos schedules eight hours a night because, in his words, “If I slept four hours, I’d have more hours to work, but would my decisions be as high quality? Probably not.” Bill Gates said reading the science of sleep changed his behaviour. Warren Buffett admits he’s “no good” without proper rest. Arianna Huffington literally collapsed from exhaustion before becoming a sleep evangelist. She now swears by eight hours a night and credits it with making her sharper, calmer and more productive. Even LeBron James reportedly takes naps on game days!

---

Final thoughts

I hope I’ve convinced you not just of the importance of sleep, but of how it can be used as a performance-enhancing tool. Whether you’re trying to avoid burnout, lead a team, get promoted or make better decisions, skipping sleep does the opposite of what you think it does. The most successful people aren’t the ones working through the night. They’re the ones who know recovery is part of the job. If you want to kick goals in your career, start by doing the simplest thing: go to bed.

If you found this article insightful, please consider subscribing or sharing it with someone who may find it relevant.