Earlier quoted context omitted.
Exercise seems to stimulate the mechanisms it’s claiming stress depresses, so probably no.
But exercise does use lots of energy. Probably more than stress.
300 calories is about the same as 30 minutes of zone 3 cardio (70-80% max heart rate, i.e. pretty high perceived exertion).
Most people in an exercise routine would only do that a couple times per week.
An "overactive" brain, day in day out, could add up to more than most people deliberately exercise.