Dr. Mahler:

Each summer my breathing is worse when it is humid outside.  On those days, I need to stay inside my apartment with fan and AC going. Why does this happen? I know others who have COPD also complain that high humidity is bad for their breathing. Thanks.

Bill from Somerset, PA

Dear Bill,

We all feel uncomfortable when it is hot and humid outdoors. Generally, healthy people do not complain of breathing difficulty in these conditions, However, it is quite common that those with asthma and COPD note that “it is harder to breathe” when the air is hot and humid.

There may be a few reasons for the effect of hot/humid weather on your breathing.

  1. Hot and humid weather can cause narrowing of the breathing tubes (bronchoconstriction) and may trigger coughing. This can be due to irritation of nerves (C-fibers) that line the inside of the breathing tubes.
  2. High humidity can trap air pollutants like smog in the air. Breathing in these pollutants can also cause the breathing tubes (airways) to constrict making it harder to breathe.
  3. Feeling uncomfortable can aggravate anxiety which increases how fast we breathe and make it more difficult to breathe.

Recommendations are to stay indoors to avoid the heat and humidity. Stay as cool as possible by using air conditioning as you are doing. Try to keep up with an exercise program in your apartment or by going to an air conditioned workout area or fitness center.

Stay cool and be as active as possible.

Donald A. Mahler, M.D.