Arizona Air Quality: Ozone and Outdoor Exercise

I am discussing air quality in Arizona, particularly as it affects patients with allergies and asthma. Previously, one of the most important pollutants, Ozone was discussed and in this post I will continue with some of the special problems associated with ozone exposure and outdoor exercise.

For a number of reasons, athletes are particularly vulnerable to the adverse effects of air pollution.  A distance runner training for a marathon or a cyclist getting ready for a century ride, will spend hours every day inhaling huge volumes of air during the course of a workout. In fact, a cyclist may inhale 80 liters of air a minute for an hour during a race.


Cyclists on South Mountain. Notice haze sitting over Ahwatukee

Exercise not only increases the volume of air that we breathe, but the high velocity of air movement sends particles deeper into the lungs.  Blood supply to the lung in also increased to absorb more oxygen, which will also allow greater absorption of any contaminants found in the air. In addition, many athletes breath through there mouth when exercising, bypassing the filtering effect of the nose.

The end result is that during exercise, the tissues of the nose, sinuses, airways, and lungs endure intense exposure to particulate and vapor pollutants such as ozone.  Obviously the greatest risk of exposure to ozone is likely to occur when exercising in the city close to traffic, particularly in the summer when the sun is shining, but because ozone can travel great distances, you cannot escape it’s effect if you live and exercise in a more rural part of Arizona, such as Ahwatukee or Cave Creak.

Because of the increased exposure to the oxidizing effects of ground level ozone with exercise, the cells lining the respiratory track can be injured. In fact, studies have shown that exposure to ozone can cause the lining of the airways to become “leaky” allowing other particles in the air such as pollen and mold spores to have greater access to our immune system, aggravating and even possible causing, allergies and asthma.  Many studies have shown that children living close to automobile traffic have increased lung problems including asthma.

Long distance runners have been found to have reduced mucocilliary function in the nose. The mucocilliary system helps to clear toxins and debris from the respiratory system and is important in our defense against infection, so a weakness in this system increases the potential for further injury and damage to the airways from air pollution.

Exposure to ozone can cause a variety of immediate symptoms including nasal and throat irritation, coughing, wheezing, shortness of breath, and pain with deep inspiration.  In addition, a measurable decrease in lung function and exercise performance can occur which worsens the longer you exercise.    Ozone exposure can cause inflammation in the airways resulting in painful breathing.  This combination of reduced lung function and painful breathing can significantly limit an athlete’s ability to perform.

Interestingly, the respiratory symptoms associated with ozone exposure mimic exercise induced bronchospasm.  Unlike EIB however, ozone related symptoms do not improve with asthma medications such as albuterol.  In some cases, ibuprofen and other non-steroidal anti-inflammatory agents have been helpful in reducing the pain, coughing, and breathing limitation associated with ozone induced inflammation.