In general, Americans don't get much exercise. With cars to get us to work or anywhere we want to go, desk jobs, and TV watching, it's a wonder we get any exercise at all.
The surgeon general recommends 30 minutes of activity daily to maintain a healthy lifestyle. Whether you actually get this amount or not, if you think you're doing enough to be healthy, you may get the same benefits.
A study was conducted on this effect using female housekeepers. Generally housekeepers are active - they clean around 15 rooms a day, and each one takes 20 to 30 minutes.