Langer decided / to do an experiment.
She told / half of the housekeepers / that their jobs / involved a lot of physical exercise.
She told them / that pushing a vacuum cleaner, / changing sheets, / and cleaning a bathroom / required a lot of energy.
She told / half of the housekeepers / that their jobs / involved a lot of physical exercise.
She said / these activities / used the same amount of energy / that people use / when they work out / at the gym.
After a month, / Langer retested / all the women.
This time, / the results / were different.
Half of the housekeepers / were thinner, / fitter, / and healthier.
These / were the housekeepers / who thought / they were working out.
In fact, / these housekeepers / had not done / anything differently.
The only change / was in their minds.
They believed / they were getting exercise.
They believed / they should get / fitter / and healthier.
As soon as / the housekeepers believed that, / their bodies showed / positive effects.