Exercise

of late i have been wondering how beneficial, if at all, my everyday activities are toward keeping me somewhat healthy. #1 mode of transportation: bicycle. obviously this requires a certain amount of physical exersion. since i tend to ride everywhere at top speed, pedaling with all my might, it is often a considerable amount of work. however, since campus isn't really all that big, going at top speed gets me around pretty timely, and i'm not actually working hard for very long. is it unhealthy to walk out of my room, hop on my bicycle and get my heart really pounding for about 3 minutes, and then go sit down in a class room? and then leave and get it pounding for 2 more minutes going to my next class? and so on, several times a day? whatever. just some thoughts from someone who should be reading history.