Yes, but before I break my arm patting myself on the back, let me tell you I was wearing a step pedometer, and only one mile was "exercise" done outside. The rest was my normal activities at home, and going out twice to shop. This week I read, "Using pedometers to increase physical activity and improve health" (a review article) in the Nov 21, 2007 issue of JAMA (many public libraries have a subscription). The researchers had reviewed 26 published studies that reported on pedometers among outpatients, 8 randomized controlled trials, and 18 observational. The conclusion was that use of a pedometer is associated with significant increases in physical activity and significant decreases in body mass index and blood pressure. This was across all ages, races, gender, and state of health.
Some guidelines specifically recommend 10,000 steps a day, although I don't know that this goal would change the outcome. So, ladies, clip on that pedometer. I'm not sure why it works, but people, me included, seem to increase their activity level when using a pedometer.