As I write this, I am less than two weeks away from my highly anticipated family vacation. We will be going with two other families, so the usual abundant memories should be double. However, being the fitness enthusiast that I am, there is a bit of anxiety about visiting the "Happiest Place On Earth". This is due to the fact that the Los Angeles metropolitan area has placed #1 on the list for most ozone pollution for the fifth consecutive year. As well, it has a detrimental amount of particle matter (soot, among other things) and is also the smoggiest city in the U.S., according to the American Lung Association. With this information I am betting that the fit folks of Los Angeles either seek shelter while working up a sweat or they endure burning lungs and reel from inadequate amounts of oxygen while exercising outdoors.

Air pollution can greatly impact an individual's cardiovascular efficiency in many ways. This is due to the pollutant's (e.g., carbon monoxide, ozone, etc.) ability to infiltrate the respiratory system. During normal breathing, most people will use their nose to channel oxygen to their lungs. This route serves as a filtering vessel utilizing your mucous membranes to snag particle matter as well as soluable gases before they can penetrate through to your lungs. When someone is performing a higher impact activity (e.g., running), there is an inclination to begin mouth breathing. This act bypasses your body's natural filtration process and more pollutants are received into the lungs. From the lungs, the pollutants will circulate throughout the body via the bloodstream. The results include bronchial vasoconstriction (airway opening becomes smaller), lung tissue can be compromised from alveoli damage and the capacity for oxygen transport is decreased. The exercising individual will experience less oxygen entering the bloodstream, which will result in an inadequate supply of oxygenated blood to the muscles. End game is that the physical performance of that individual will be substantially compromised.

If you find yourself visiting a city with poor environmental conditions, your best bet is to pay the drop-in fee at the nearest gym; this fee can range from $7.00 - $15.00 per day. While the average healthy adult can withstand up to a 15% increase in carbon monoxide, cardiac and pulmonary patients can be adversely affected by as little as a 5% increase. Children are also more susceptible to ill effects. And, exposure to these pollutants can stay in the bloodstream for hours. That means if you were around an unusual amount of toxins in the morning (commute traffic, cigarettes), your afternoon workout could be more labored than usual.

While every city or even small towns can have their own form of contaminants, it is up to you to make wise decisions when choosing a safe environment in which you perform your exercise.

Cleanest U.S. Cities (Ozone%)

1. Ames-Boone, IA

2. Bellingham, WA

3. Brownsville-Harlingen-Raymondville, TX

4. Colorado Springs, CO

5. Duluth, MN

Cleanest U.S. Cities (Particle Matter)

1. Santa Fe-Espanola, NM

2. Honolulu, HI

3. Cheyenne, WY

4. Great Falls, MT

5. Farmington, NM

SMOGGIEST CITIES

1. Los Angeles-Riverside-Orange County, CA

2. Fresno, CA

3. Bakersfield, CA

4. Visalia-Porterville, CA

5. Houston-Baytown-Huntsville, TX

6. Merced, CA

7. Sacramento-Arden-Arcade-Truckee, CA

8. Hanford-Corcoran, CA

9. Knoxville-Sevierville-La Follette, TN

10. Dallas-Fort Worth, TX