How Multitasking Reduces Efficiency and Increases Stress

The idea of multitasking is alluring—it promises that you can check off two (or three) to-dos at once, saving time and maximising productivity. But here’s the reality: multitasking is an illusion.

When you multitask, your brain doesn’t truly perform multiple tasks simultaneously. Instead, it switches rapidly between tasks, a process known as "task switching." This constant toggling creates what cognitive scientists call “switch costs,” the mental and time delays caused by shifting focus.

Research led by Dr. David E. Meyer at the University of Michigan found that switching between tasks can reduce efficiency by up to 40%. That’s right—nearly half your effort is wasted when you multitask. Whether it’s switching between writing an email and answering a colleague’s question or juggling multiple client calls, your productivity takes a hit every time your attention shifts.

Let’s closely examine how the brain works to understand why multitasking reduces efficiency.

Your brain has a prefrontal cortex responsible for focus, decision-making, and prioritising tasks. When you focus on one task, the prefrontal cortex operates like a laser, directing all its energy toward the goal. But when you try to tackle multiple tasks, your brain divides its resources, forcing the prefrontal cortex to alternate focus between each task.

When you divide your attention between several tasks, it weakens your performance in several ways:

A study published in the Journal of Experimental Psychology by Rubinstein, Meyer, and Evans showed that multitaskers took significantly longer to complete tasks and made more errors than those focused on one task at a time.

Multitasking harms your efficiency and mental and emotional well-being. Each time you switch tasks, your brain experiences a spike in cortisol, the stress hormone. Over time, this creates a cycle of chronic stress, leading to exhaustion, irritability, and even health problems like high blood pressure and insomnia.

A study by Gloria Mark, a researcher at the University of California, found that frequent task interruptions increase stress and reduce the ability to focus intensely on meaningful work. This is why multitasking overwhelms you even when you haven’t accomplished much.

When your brain is in overdrive, it doesn’t just affect your work—it spills over into your personal life. You find yourself distracted in conversations, unable to relax fully, and constantly feeling like there’s more to do.

So why do so many people cling to multitasking? Because it feels productive. When you bounce between tasks, your brain gets a dopamine hit—a feel-good neurotransmitter associated with novelty and reward. This creates the illusion that you’re achieving more, even as your efficiency plummets.

Multitasking also creates a false sense of urgency. You may feel like you’re handling everything at once, but in reality, you’re doing more surface-level work and neglecting tasks that require deep thought or creativity.

For leaders, entrepreneurs, and high achievers, multitasking isn’t just counterproductive—it’s dangerous. In high-stakes environments, where every decision matters, the ability to focus intensely can mean the difference between success and failure.

When you multitask, you risk:

If multitasking is the enemy, single-tasking is the antidote. Single-tasking is the practice of focusing on one task at a time, giving it your full attention before moving on to the next.

Here’s how to embrace single-tasking:

Mindfulness plays a crucial role in breaking the multitasking habit. Practising mindfulness trains your brain to stay present, resist distractions, and fully engage with the task.

Start small:

Some of the world’s most successful leaders credit their achievements to single-tasking. Warren Buffett, for example, is known for his laser-like focus on a few key priorities, a practice that has driven his extraordinary success. Similarly, Steve Jobs famously emphasised the power of saying “no” to distractions to focus on what truly matters.

These leaders prove that doing less—but doing it better—yields far more excellent results than spreading yourself too thin.

So, if you consider yourself a multitasker, are you ready to abandon that and embrace single-tasking? If not, let’s examine the long-term benefits and see if that will change your mind.

When you leave multitasking behind and embrace single-tasking, the benefits extend beyond your immediate productivity. This shift fundamentally changes how you approach your work, relationships, and well-being, leading to lasting improvements in nearly every area of your life.

Focusing on one task at a time allows you to complete tasks faster and at a higher quality. The time and energy saved from avoiding constant task-switching accumulate, allowing you to take on more meaningful projects without the mental fatigue of juggling multiple responsibilities. Over weeks and months, this consistent focus translates into a noticeable boost in overall output and performance.

For example, could you write a report while intermittently answering emails? If you did, you would multitask, and the job would stretch over hours, with the added frustration of having to spend time fixing errors caused by divided attention. On the other hand, single-tasking ensures the report gets done in less time, with fewer mistakes, and without the lingering stress of unfinished tasks hanging over you.

Now, here's the thing: Long-term single-tasking enhances your brain’s ability to focus and process information deeply.

In The Organized Mind, cognitive scientist Daniel Levitin explains that multitasking overworks the brain’s executive system, diminishing its capacity to perform at a high level. By practising sustained focus, you preserve and strengthen this critical part of your brain, improving problem-solving, creativity, and decision-making.

Imagine how this plays out in a leadership setting: When fully engaged in a meeting or strategy session, you can contribute deeper insights and make sharper, more impactful decisions.

Quitting multitasking is one of the most effective ways to reduce chronic stress. When you’re no longer trying to juggle too many tasks simultaneously, your brain can manage challenges without feeling overwhelmed. The constant cortisol spikes associated with multitasking give way to a calmer, more measured approach to problem-solving.

Over time, this shift builds resilience. You become better equipped to handle high-pressure situations because your mind isn’t scattered. Moreover, leaders who embody this sense of calm inspire confidence in their teams, creating a ripple effect of reduced stress throughout their organisations.

Multitasking affects your work and spills over into your interactions with others. For example, have you ever tried to hold a conversation while checking your phone or finishing a task? It sends a clear message: “I’m not fully here.”

When you quit multitasking, you regain the ability to be present with others. Whether it’s a colleague seeking advice, a client discussing needs, or a family member sharing their day, giving your full attention to them strengthens the relationship because they feel valued. Over time, these moments of genuine presence help build trust, deepen relationships, and enhance collaboration.

Chronic stress associated with multitasking affects more than just your mind—it also affects your body. Prolonged stress is linked to a host of health issues, including high blood pressure, insomnia, and weakened immunity. Focusing on single-tasking and reducing stress creates space for healthier habits and a more balanced lifestyle.

Imagine finishing your workday feeling accomplished rather than drained. This mental clarity allows you to prioritise exercise, healthy eating, and restorative sleep, reinforcing your physical health and enhancing your ability to focus and perform.

Perhaps the most profound benefit of quitting multitasking is the fulfilment of giving your best to each task. When you immerse yourself fully in what you’re doing—whether it’s a work project, a personal goal, or time with loved ones—you experience a deeper level of satisfaction.

This fulfilment comes from knowing that you’ve done your best, free from the distractions and half-measures that multitasking often entails. Over time, this leads to greater confidence in your abilities and a stronger sense of purpose in your professional and personal life.

In the professional world, quality trumps quantity. Leaders and high performers who focus on single-tasking stand out for their ability to deliver exceptional results. They’re not the ones rushing to finish work at the last minute or making excuses for errors caused by divided attention. Instead, they produce thoughtful, high-impact work that drives long-term success.

By building a reputation for focus and excellence, you open doors to new opportunities, whether career advancement, leadership roles, or exciting projects that align with your passions.