From Gina Trapani at Fast Company:
When your brain switches its attention from one task to another, it takes time to get into a new train of thought. You lose any momentum you had on the first task, which costs you on the next switch. On the internet or in an office where distractions abound, switching tasks can cost hours. A recent study showed that office employees who were interrupted while they worked took an average of 25 minutes to get back to what they started.
If you’ve got work that requires engaged thinking—like reading, writing, or even just a serious phone call, stop juggling and start single-tasking. For example, if you’ve got a dozen emails to answer and presentation slides to prepare, complete the slides before you look at the email. You’ll get both jobs done faster than the juggler who switches between the email and the slides every few minutes.
You already know that some kinds of multi-tasking can be hazardous to your health, like texting while driving or blow-drying your hair while you’re in the bathtub. When it comes to splitting your attention between tasks, remember the difference between multi-tasking and juggling. When you have the choice, stop juggling and get things done faster–one at a time.