Michelle M. Klinek, M.D.

February 3, 1997

EXERCISE-INDUCED ASTHMA

Exercise is a very important part of many people's life.

We encourage the participation in organized sports such as little league baseball, soccer, swim team, dance and track for example. With the stance on helping to prevent osteoporosis, exercise is being promoted. For many with known asthma and for some who don't, exercise is often less than enjoyable secondary to the effect of exercise on the respiratory track. The message of this talk is to tell everyone that with proper recognition and treatment of this problem, most adults and children can participate in sports safely and enjoyably. During the summer Olympics, many of the athletes suffered from asthma, but were able to do some pretty incredible things. For example, Tim Dolan who reports being diagnosed as a severe asthmatic at age 12 won a gold medal for the 400m individual medley in swimming.. He has described his difficulties with exercise induced asthma "It's like a vise on my chest". Another Olympian is Amy Van Dyken who until 6yo had such significant EIA that she couldn't walk up steps. She choose swimming because of the humidified environment.

Samples from the LIFE QUALITY TEST from the ACAAI

Answer Yes or No

1. When I walk or do simple chores, I have trouble breathing or I cough

2. When I perform heavier work, such as walking up hills and stairs or doing chores that involve lifting, I have trouble breathing or I cough.

3. Sometimes I avoid exercising or taking part in sports like jogging, swimming, tennis or aerobics because I have trouble breathing or I cough.

4. I have been unable to sleep through the night without coughing or having shortness of breath.

Overview

Definition of Asthma= Recurrent Wheezing It comes from the Greek word for PANTING or labored breathing. SX: cough, wheeze, chest tightness

Causes of Asthma

1. Allergies - the mechanism involves an inherited oversensitivity of the immune system to the harmless things called allergens ie. pollens, pet dander, molds, foods, bee venom. If one parent has allergies, there is a 50% chance each child will, if both parents have allergies, this goes up to 75%. The allergens bind to the allergy cell called the mast cell resulting in the release of chemicals such as histamine and inflammatory mediators. Histamine causes mucus production and airway spasming and the inflammation perpetuates the cycle by recruiting more cells.

2. Irritants - Viral infections, Cigarette smoke, certain Occupational exposures, and exercise work to irritate or change the respiratory tree's surface either by destruction of the lining of the lungs or by changing the environment ie drying or the presence of different cells.

3. Lung Disease - Cystic Fibrosis, Alpha 1 Antitrypsin Deficiency, Vasculitis, Obstructions ie vascular abnormalities, tumors, etc.

3 Parts of an Asthmatic Attack

Normal versus Asthmatic Airway

Air travels through the larger airways called the bronchi into the smaller airways called the bronchioles and then into the air sacs or alveoli where there is an exchange of oxygen for carbon dioxide. Usually the airways are widely patent; however with asthma the following happens:

1. Inflammation from a triggering event i.e. cold air, pollution, allergen, exercise

2. Mucous production causing some blockage of air flow through airways

3. Contraction of the muscles around the airways causing airway obstruction

Epidemiology

The prevalence of asthma has increased by nearly 40% over the last decade

1. Increased recognition 2. Air quality

2. Increased life expectancy for the young and old 3. ? (sick building sy)

More than 1 in 10 people will have difficulties with asthma

Over 14 people die a day from asthma

Asthma costs tolled more than 6 million dollars in 1990

Who is at risk for Exercise-Induced Asthma?

A. Those with known asthma and allergies

Those who are known asthmatics and those who have other forms of allergy have a very high risk of having EIA. One study showed that 70-80% of asthmatics will have EIA and those with nasal symptoms alone have a 40% chance. These people have baseline inflammation from their unique triggers such as the allergens or perhaps from cigarettes. They are already primed and are ready to respond.

In these people environmental control is important ie; pollen, dustmite, pets etc.

B. Those with only asthma during exercise

Another group are those people who have not been diagnosed with allergies or asthma and have exercise intolerance secondary to EIA. This can account for an additional 7% of the population. These are the people who often don't benefit from our help because they are unrecognized. A study at the University of Iowa evaluated student-athletes. 12% gave a history of asthma, 19% experienced chest tightness, cough, wheeze, and shortness of breath on exercise. This demonstrates the lack of recognition of EIA in many people.

What is EIA

A. Definition:

An acute, reversible, self -limited episode of airway obstruction that occurs during or after physical activity. Normally air enters the nose where it is warmed and humidified. From there it travels into the airways which make up the lungs where it drops off oxygen and picks up carbon dioxide. It then leaves the airway and travels back up to the nose and out. During exercise with a more rapid respiratory rate, air is inhaled through the mouth and bypasses the warming and humidification of the nose. This leads to cooling and drying of the airways leading to tightening and spasming of the airway muscle.

This mechanism helps to explain why some sports are better tolerated than others.

Sports that take place in cold, dry air like running, soccer, and cross-country skiing are very asthmogenic.

Sports that take place in humidified air or that don't involve long periods of constant exercise are better tolerated such as swimming, weight-lifting, wrestling, volleyball, short-distance track, tennis, baseball, golf and gymnastics.

B. Clinical pattern

EIA has a very characteristic pattern (FIGURE IN PEAK EXPIRATORY FLOW RATE). During the first few minutes of exercise, adrenaline is released. This results in relaxing of the airways and good air entry and exchange. However by 5-12 minutes of exercise airway obstruction begins and air flow through the lungs is hampered.

An interesting observation has been made. Once EIA has occurred the body appears protected from another episode if exercise occurs again in a 30-90 minute period. This is called a refractory period. The mechanism underlying this is unknown. Physicians and coaches take advantage of this observation by encouraging a thorough warm up of the body and muscles.

Anther factor to be considered is Air Pollution. Exercise speeds the rate and depth of breathing, increasing absorption of pollutants. Pregnant women and those with COPD are also at risk. In pollution there is NO2, CO2, and SO2. In 1948 in Donora, PA over 20 people died when the air pollution became so concentrated when waste products from a mill was trapped close to earth by a certain weather system.

FACTORS THAT DETERMINE AIRWAY RESPONSE TO EXERCISE

Duration of exercise

Intensity of exercise

Type of exercise

Interval since last episode of EIA

Ambient air conditions - temperature, humidity, pollution

Recognition - the hardest step

A. History and Observation

In older children and adults complaints may be heard about chest tightness, coughing or wheezing, in younger children the parents may notice it difficult for their child to keep up with his peers. He may be the first child to stop running or riding bikes. It is important to keep in mind that most children want to run and play. Being a couch potato may be a red flag that your child suffers from EIA. Some coaches may suspect an athlete of not trying her best when, in actuality the child has unrecognized EIA. Often in older children and adults trouble with exercise is associated with deconditioning.

B. Testing

1. Exercise challenge test - in the office or even at home we can monitor the ability to blow out air before and after exercise. When airway narrowing occurs, less air can be expired and the number of liters of air released are less. When there is more than a 10% drop in peak flow readings, a diagnosis of EIA can be made.

In the laboratory we will have children walk on a treadmill for 6-8 minutes, then check their peak flows at regular intervals. \

2. Methacholine Challenge test - when there is a high index of suspicion for reactive airways, but documentation is unable to be attained, this test is employed. People with reactive airways will tend to have airway spasming at a lower concentration of this medicine than those without asthma.

Treatment Plan

1. Ensure there are no underlying problems that contribute to EIA such as allergies, allergic rhinitis. Consultation with your family doctor or an allergist to discuss the issue and perform a complete physical exam to determine if other problems are going on and to assess the degree of EIA.

2. Review of proper warming up activities and other measures to help decrease EIA

-use of a face mask can help warm and humidify air

3. Use of proper medications

If the person is well and no underlying inflammation is present in the lungs, 90% are well controlled with an inhaled bronchodilator 15 minutes prior playing the sport. i.e. proventil, ventolin, albuterol, maxair.

If EIA persist, the addition of Cromolyn or Nedocromil can be used 15 minutes after the albuterol.

5. Review of symptoms where additional meds or discontinuing sport are necessary.

4. Proper delivery system - Inspirease and Aerochamber for those with difficulty using MDI

Tips for Avoiding EIA

Begin your warm-up period by taking medicines

Warm up with 10-15 minutes of stretching

Work out slowly for 10 to 15 minutes

Following warm-up start your workout

Wear a face mask or scarf over your nose and mouth while exercising during cold weather

Follow your workout with a 10-15 minute cool down.

Lots of good programs

* Asthma Olympics by the American Lung Association

* Asthma Camp this summer

* Lots of Help Groups

ALA

Mothers of Asthmatics

Asthma and Allergy foundation