
Multitasking
Try this: Say the letters abcdefg and then the numbers 1234567 in succession. Now, say a1b2c3d4e5f6g7. See how much longer that took? Switching between two tasks causes your brain to slow down, according to economist and management consultant Caroline Webb, who uses this example in her book How to Have a Good Day. One professor and psychologist at the Human Information Procession Laboratory at Vanderbilt University even found that people working on two tasks simultaneously took up to 30 percent longer and made twice as many errors as those who completed the same tasks in sequence. Schedule your day into segments where you can try to focus on one task at a time with the much healthier alternative of monotasking.

Chatty co-workers
Studies have found that people can only understand 1.6 conversations at a time—and our own inner monologues already count as one. “If you’re in an office where you can overhear one person talking right next to you, they’re taking up one of your 1.6,” sound expert Julian Treasure said on NPR’s TED Radio Hour. “Unless you put headphones on, that person’s conversation is inevitably going to be decoded in your brain because we’re programmed to decode conversation.”

Access to email
One study of Microsoft employees found that after they read an email—whether they replied to it or not—it took them 15 minutes to fully regain their train of thought. Close your email when you’re working on a project that requires your full attention. If your boss objects, brainstorm a way for truly urgent messages or phone calls to reach you.

Interrupting yourself
Studies have found that office workers are interrupted—or self-interrupt—every three minutes or so. And on top of the time it takes to address the interruption, some experts say it can take close to 25 minutes to return to the original task. Try to minimize temptation by eliminating unnecessary notifications (turn off group-chat alerts, shut down your email, put your phone on airplane).

Stress
Stress can impact your focus and the quality of your work. “It competes with your cognitive centers—the areas in the brain that are responsible for quick, sharp thoughts—so being anxious or stressed drags focus down even further,” Timothy Wilens, MD, an associate professor of psychiatry at Harvard Medical School, told Health. Try these expert stress management tips.

Not jotting down
If a genius idea pops into your head during a time you’ve already decided to devote to a different task, write it down and return to it later. The same thing goes for forgotten to-do list items and reminders. Trying to remember these things in your head can hurt your focus (and increase the chance that you’ll forget them again).

Messy desk
One survey of office workers found that 82 percent said that being organized improved their performance. The workers said clutter resulted in lost time, being late to meetings, and missed deadlines. What’s more, one Princeton neurologist found that just the sight of clutter can take a toll on focus by competing for your attention. Do a daily scan of your work space and sort through any attention-grabbing mess.

Your day is highly fragmented
Try to work on major projects when you have windows of time that are 90 minutes or longer, which will allow you to engage in deep concentration. Further, eliminate distractions during this time. One top-performing Wharton School professor works for days in isolation, writes Cal Newport in his book Deep Work. The professor minimizes distraction by putting an out-of-office auto-response on his email. “By consolidating his work into intense and uninterrupted pulses, he’s leveraging the following law of productivity: High-Quality Work Produced = (Time Spent) x (Intensity of Focus),” writes Newport.