COPD and the Seasons

The imminent approach of summer will bring seasonal changes that can affect people with chronic obstructive pulmonary disease, but the truth is that there is no good season for COPD patients. Factors associated with both warm and cold weather can exacerbate COPD and cause problems for those living with it.

We know that environmental conditions, including outdoor and indoor air pollution, can contribute to causing COPD. The inhalation of irritating particles can cause the mucus glands in the bronchi to produce more mucus than normal, leading to thickening and inflammation of the bronchi walls.[1]

But air pollution also is one of the common causes of COPD exacerbations, in which the airways become blocked and COPD symptoms suddenly get worse. Exacerbations can cause infection in the airways and lead to hospitalization, so it is important for patients to be able to recognize symptoms, which may include:

  • Worsening of a stable condition;
  • Increased difficulty breathing;
  • Increased wheezing, coughing, mucus production;
  • Change in the appearance of mucus;
  • Chest tightness;
  • Irritability or change in personality;
  • Fluid retention;
  • Forgetfulness, confusion, slurring of speech, sleepiness.[2]

In addition to air pollution, changes in the weather and air temperature can trigger or worsen COPD symptoms. Both hot and cold air cause problems,[3,4] because each type of weather brings its own set of breathing irritants.

Spring/Summer and Hot Weather
COPD symptoms can flare on days of high heat and humidity, partly because these conditions often are accompanied by high levels of smog. COPD patients should try to stay indoors in an air-conditioned environment on hot, humid days.[4] High temperatures can cause dyspnea and exhaustion as the body works harder to breathe and maintain a normal body temperature. Warm air also can cause the airways to constrict, possibly causing bronchospasms. Humidity causes shortness of breath because humid air contains more moisture and less oxygen, making it heavier and harder to breathe.[5]

When hot, humid air is accompanied by outside allergens common to warm seasons, COPD patients can have even more difficulty breathing. According to the Asthma and Allergy Foundation of America, one out of five people in the United States have asthma and allergies, including those that also may have COPD, and many people have multiple allergies. “Outdoor allergies (also called “seasonal allergic rhinitis” (SAR), “hay fever,” or “nasal” allergies) occur when allergens that are commonly found outdoors are inhaled into the nose and the lungs causing allergic reactions. Examples of commonly inhaled outdoor allergens are tree, grass and weed pollen and mold spores.”[6]

Any substance that causes an allergic reaction can exacerbate COPD symptoms because exposure to an allergen typically narrows the airways and increases mucus production, making it harder to breathe.[7] However, there is no clear connection between allergies and COPD, although many believe that patients with compromised airways caused by allergies or asthma are at increased risk for COPD and some believe allergies and asthma are the early stages of COPD.[8] Even so, current COPD treatment guidelines do not include strategies for the management of allergies in COPD patients.[9]

Recent research out of Johns Hopkins University found that COPD patients with allergic disease have higher levels of respiratory symptoms and are at higher risk for COPD exacerbations. In a press release announcing results of the study, Nadia N. Hansel, MD, MPH, associate professor of medicine at the Johns Hopkins Asthma & Allergy Center and one of the researchers on the project, commented, “Although allergic sensitization and allergen exposure are known to be associated with impairments in lung function, the effects of allergic disease on respiratory symptoms in COPD patients has only recently been studied.” She added that the study’s findings suggest that treatment of active allergic disease or avoidance of allergy triggers may help improve respiratory symptoms in COPD patients and that more studies of the relationship between allergic disease and COPD are needed.[9]