Anxious? Photo: SuperStock/Getty Images

I used to think that a life free of anxiety would be awesome: no more bitten fingernails, more relaxation, more mental bandwidth — instead of worrying, I could think about cool things like bears in pools or Keanu Reeves classics. But after speaking with David Barlow, the founder and director emeritus of the Center for Anxiety and Related Disorders at Boston University and author of Anxiety and Its Disorders, I have a newfound appreciation for the worrying voice that shows up in my head time and again.

“Humans are particularly well-situated to be able to anticipate the future and plan for the future,” Barlow explained, and that’s where anxiety is actually quite functional. The insight tracks back half a century ago, he says, to the work of early psychologist Howard Liddell, who in 1949 was writing about how anxiety “accompanies intellectual activity as its shadow.” For example, you might have a job interview, a date, a move, some major task that needs to accomplished. “The anxiety is something that motivates you to plan your approach to these challenges in such a way that you feel you’re prepared,” Barlow said. “In doing so, you perform at a much higher level.” Anxiety — so long as it’s something that subsides and isn’t part of a full-blown disorder — is an ambassador of responsibility, nudging you to taking care of the things that you need to take care of.

Along with the very useful emotion of fear, anxiety has been “largely responsible for the survival of the species,” he says. Sensing future dangers and figuring out what to do about them is hugely valuable, survival-wise. The clan with no one worrying about fermenting enough fish for winter was the one that didn’t make it to spring. “People will accomplish more, perform better, will act in more appropriate and fruitful ways for having been anxious,” he says, so long as the anxiety leads to fruitful action and doesn’t become pathologically overwhelming.

Indeed, if someone experiences zero anxiety, look out: These people are at the extreme end of extroversion, eager of risk, seekers of thrills. The Evel Knievels of the world, known to die young. “That’s the difficulty with no anxiety,” Barlow says.