NASCAR causes hearing loss? Who knew?

So get this -- turns out that loud engines in enclosed spaces for extended periods of time aren't good for your hearing!

A new study has found that fans and drivers of NASCAR are subjecting themselves to dangerously high levels of sound. I know, I know, this sounds like one of those studies in obviousness, like "American men more interested in pictures of sexy women than clipping coupons," or whatever. But there's some truth and good recommendations behind these findings.

The National Institute of Occupational Safety and Health has determined that the most noise workers should be exposed to in the course of a normal eight-hour day is 85 decibels. That's the top legal noise level; it's about the same volume as a dial tone held right to your ear, for instance.

However, the sound at a NASCAR track can reach 140 decibels -- you know, right after "gentlemen, start your engines" -- and can last for three to four hours (or much, much more, if you're at Pocono).

The NIOSH conducted studies at the Indianapolis Motor Speedway, Bristol Motor Speedway and the Kentucky Speedway using a variety of sound meters and over the course of the entire race weekend. And the findings were a bit eye-opening (and ear-damaging): The OSHA eight-hour limit was exceeded in less than a minute for drivers, in just a few minutes for team members, and within an hour for spectators.

Now, bear in mind that this is with no ear protection whatsoever. Drivers always wear ear protection, as do most crews. But fans often revel in the noise, which -- to put it mildly -- isn't the wisest approach. Hearing loss is mostly irreversible, so this is worse than hanging in the infield without sunscreen.

It's a particularly timely study, as Bristol was the loudest of the three tracks measured and, anecdotally, the loudest in NASCAR. Its small size, bowl-shaped configuration and metal supports all keep sound reverberating back and forth inside Thunder Valley.

"Most spectators assume that a few hours of recreational noise exposures are harmless," said the NIOSH's Chucri A. Kardous and Dr. Thais Morata, who conducted the study, "but noise exposures do add up and data from our research show otherwise." NIOSH is also preparing similar studies on rock concerts and those freaking vuvuzelas from the World Cup.

So, bottom line: If you're headed to Bristol this weekend, wear your earplugs. The race is plenty loud without feeling like your eardrums are getting run over by 43 vehicles.