Take a deep breath, readers in Oklahoma City, Okla.; Birmingham, Ala.; and New Orleans. Just kidding, we know you can't! These are the country's most congested cities, according to a new survey from Sperling's BestPlaces and Breathe Right Nasal Strips. 

Seven categories were taken into consideration when ranking the most stuffed-up cities: pollen count, molds and spores; air pollution; incidence of flu; purchase habits of congestion products; prescriptions of congestion relief drugs; smoking; and climate.

Surprised a smog-heavy city like Los Angeles didn't top the list? So was Dr. Michael Breus, a board-certified sleep disorder physician. "I kind of expected certain cities that may be known for more pollution would be at the higher end of the scale," Breus says. "Everybody always talks about smog in certain places, like Los Angeles. I would’ve expected that to be easily in the top 10 and it wasn’t." (Los Angeles was ranked no. 38.) 

As Breus explains it, we can also safely assume these congested cities rank very high in the following categories: most likely to sleep poorly, most likely to mouth-breathe and most likely to snore. 

"One of the things we know is the deeper we get into sleep, the more your respiration slows down so you’re not breathing nearly as much air as the rate you were in your lighter stage of sleep. And congestion reduces the amount of air that's coming in no matter what," Breus explains. "Then when your body hits deep sleep, oxygen levels go down so your brain says, 'Wake up! You need to breathe!' It’s not a full on apnic situation, but it’s a red flag to your brain (that you're) not breathing too well in these deeper stage during sleep."

This is the slippery slope that usually leads to mouth-breathing, Breus says. "I’ve got all this blockage in my nose -- boom! My mouth falls open. Then your mouth gets dry, and you wake up because you’re uncomfortable." 

And when the mouth is forced open during sleep, snoring is more likely to happen. All that mouth-breathing causes pressure to develop behind your uvula and soft palate, which begin to vibrate, which is what causes those lovely snoring sounds. 

Here's what you're really waiting for: the list of the top 20 most congested cities. How did your hometown rank? How should it have ranked? 

1. Oklahoma City, Okla.
2. Birmingham, Ala.
3. New Orleans, La.
4. Louisville, Ky.
5. Memphis, Tenn.
6. San Antonio, Texas
7. Dallas, Texas
8. Charlotte, N.C.
9. Houston, Texas
10. Philadelphia, Pa.
11. St. Louis, Mo.
12. Indianapolis, Ind.
13. Richmond, Va.
14. Austin, Texas
15. Pittsburgh, Pa.
16. Detroit, Mich.
17. Columbia, S.C.
18. Nashville, Tenn.
19. Tampa, Fla.
20. Cincinnati, Ohio

Related:

• Ahem! What is a 'frog in the throat,' anyway?
• Got the crud? How to color-code your cold
• Mouth-breathing gross, harmful to your health

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