When was the last time you experienced true silence?

If you're lucky enough to live in a quiet, remote place, that might be a simple question to answer. But for most urban dwellers, escaping the cacophony of car horns, constructive noise, and human chatter is a major undertaking and a rare event.

But should we all make the effort to escape our noisy world and get some peace and quiet a bit more often?

That's the subject of an utterly fascinating recent Nautilus piece by Daniel A. Gross (hat tip to the excellent Science of Us blog for pointing it out) that delves deeply into the latest research on the effect of silence on the human brain. We tend to think of silence as an absence, a lack of noise, rather than a positive condition, but according to this science, silence isn't just not bad for your brain, but actively good.

This is your brain on noise.

It's old news by now (and probably never came as much of a shock to those who live next to train tracks or would-be DJs) but a well established body of research confirms that lots of noise is lousy for your health.

"In the mid 20th century, epidemiologists discovered correlations between high blood pressure and chronic noise sources like highways and airports. Later research seemed to link noise to increased rates of sleep loss, heart disease, and tinnitus," reports Gross.

And the damage isn't just physical. Your neighbor's four yippy dogs really do stress you out, science proves. "Neurophysiological research suggests that noises first activate the amygdalae, clusters of neurons located in the temporal lobes of the brain, associated with memory formation and emotion. The activation prompts an immediate release of stress hormones like cortisol. People who live in consistently loud environments often experience chronically elevated levels of stress hormones," Gross further explains.

All of that stress adds up to a lot of lost health. The WHO has even tried to put a number on it. "The 340 million residents of western Europe--roughly the same population as that of the United States--annually lost a million years of healthy life because of noise," Gross writes.

This is your brain on silence.

Given all these studies, it shocked no one that quiet is comparatively lower stress, but scientists conducting research on the health effects of noise actually stumbled on a surprise truth -- silence is more than just the lack of noise pollution. It's an active good that has profound positive effects on us physiologically and psychologically.

The results of one mouse study led by a Duke biologist were a head scratcher for the research team, for instance. Working on the hypothesis that listening to the calls of baby mice might spur the growth of more brain cells in adults, the research team was surprised to discover that it was silence (originally included in the experiment as a control) that seemed to prompt the brain to regenerate itself the most.

"Two hours of silence per day prompted cell development in the hippocampus, the brain region related to the formation of memory, involving the senses," notes Gross, who goes on to outline a long list of other findings on the intriguing brain benefits of regular quiet time.

"Freedom from noise and goal-directed tasks, it appears, unites the quiet without and within, allowing our conscious workspace to do its thing, to weave ourselves into the world, to discover where we fit in," he says, summing up the research into the way silence can "calm our bodies, turn up the volume on our inner thoughts, and attune our connection to the world."

So I ask again, when was the last time you experienced true silence?

And should you maybe try to get away from the noise a little more regularly?