I’d classify this question as so dumb it’s actually kind of interesting, in a hair-splitting, pedantic sort of way.
At Popular Science, Daniel Engber takes a stab at answering it:
For a study published in 1998, speech-language pathologist Bridget Russell, of the State University of New York at Fredonia, asked participants to read aloud using either a quiet, normal, or loud voice while she measured their breathing rates, oxygen consumption, and energy expenditure. Russell found that continuous, normal speech is no more exhausting than sitting in silence, but quiet and loud talk both interfere with normal respiration. Most affected were men who read out loud at high volume; they took in 20 percent more oxygen.
More oxygen intake translates to higher energy expenditure. I checked, and this means that, technically speaking, “quiet and loud talk” fit the National Heart, Lung, and Blood Institute’s definition of physical activity, which it characterizes as “any body movement that works your muscles and requires more energy than resting.” But whether it fulfills the requirements of exercise, which the NHLBI defines as “a type of physical activity that’s planned and structured,” depends on whether you make shouting part of your regular exercise routine, I guess? Unclear. Though I’m inclined to side with Gawker’s Hamilton Nolan on this matter:
The gym is not a place for talk. The gym is a place for action. Action consists of doing things. Hardcore things. It could be pulling things, or pushing things, or pulling and then pushing things, or moving things around in a circle. It could be lots of things. One thing it cannot be: talking, to another person.
“Many Americans are not active enough,” notes the NHLBI. Just speculating, but I think this observation and the fact that we’re sitting here discussing whether talking counts as exercise may be linked.