14 DAY TRIAL // Doctors warn people to avoid whispering when they are cold and already have swollen vocal cords, as doing this would most likely make things worse. The lower-than-usual voice that generally characterizes those who have the flu or suffer from the common cold is caused by inflammation in the cords or of the surrounding membranes and tissues, which modify the amount of air that passes between the cords when we articulate sounds.
Because the vocal cords are very thin, to begin with, even the slightest change in their thickness is enough to trigger a massive modification of pitch and intonation in the voice.
“With a cold, several parts of the upper respiratory tract become swollen, including the vocal cords, and any tiny swelling of the cord itself or the underlying tissue space causes the voice to sound deeper or huskier because the frequency of vibration is slowed,” NewYork-Presbyterian Hospital/Weill Cornell Medical Center otorhinolaryngologist in chief (ORL specialist) Michael G. Stewart explains for The New York Times.
“In more severe cases, if the swelling is bad enough, the vocal cords can no longer vibrate, which causes the person to be unable to speak except in a whisper, which is the way ‘laryngitis’ is depicted in movies and TV,” he adds. However, when people can still move their vocal cords, it's essential that they do so while speaking aloud and not whispering or muttering, as these ways of communicating exert an extra amount of strain on the vocal cords and can make them swell even more.
The expert also says that coughing is one of the main reasons why vocal cords tend to get sore when a person has the cold, mainly because the act in itself has devastating effects on the neck region, forcing the cords to slam powerfully against each other. That's why, he pinpoints, individuals tend to lose their voice or to speak with a different one after coughing a lot.