Hotel housekeepers who were informed their work constituted exercise showed health improvements without changing physical behavior.

“And what we found was that these women, even though they hadn't changed anything in their behavior, at least that was detectable to us. They didn't work more rooms, they didn't start doing pull-ups or push-ups in between cleaning hotel rooms, as far as I'm concerned. They didn't report any changes in their diet, but they had benefits to their health. So they lost weight. They decreased their systolic blood pressure by about 10 points on average. And they started feeling better about themselves, their bodies and their work, not surprisingly.”