I'd be more alarmed by the amount of noise generated, and that being a distraction. I have a bike trainer that I ride three or four nights a week in the winter after work, typically while reviewing notes or chapters for classes I'm taking. I love it, but I'm also not learning new material. And it keeps my body loose after full days at work.
Exercise keeps the brain sharp and alert. I'd like to see more serious PE year-round with some national standards. Instill a healthy lifestyle and the country will reap the benefits. There's no reason for a HS student to not be able to do even one pull-up or run a mile in 10:00 or do 30 sit-ups. Maybe I'm biased from living in a state known for being overwhelmingly healthy and fit, but I do get alarmed sometimes when I return to Iowa or see pics from Iowa and see the size of some people including kids.
