“We can’t really do more than one thing at a time, experts say. But, generally, “when we switch between tasks, we pay what’s been dubbed a ‘switch cost,’” Dr. Wagner said. “We’re going to be slower and less accurate than we would have been if we stayed on a single task.” Speed and precision aren’t the only risks, either. Multitasking is more cognitively demanding, even when we’re doing things we find enjoyable or easy. When we multitask, we can tax our working memory, or our ability to hold and handle information in our mind, Dr. Byers explained. “The more we overload that system and the more we’re trying to keep in our brains at once, the more mental fatigue it can lead to,” she said. And other studies have found that multitasking can set our heart racing, raise our blood pressure, trigger anxiety, dampen our mood and negatively impact our perception of the work at hand.”

Multitasking Is a Bad Habit. Here’s How to Stop (Kind of).