When it comes to exercising and physical health, maybe we can flip the phrase “seeing is believing.” Perhaps, suggests a recent study from Stanford University, certain beliefs can change what we see.

This new study grew from earlier research involving 84 female hotel workers who said they felt they completed little to no daily exercise, despite the fact their job required mostly physical labor.

Researchers explained to half of them that they were meeting or exceeding national recommendations of exercising 30 minutes a day. A month later, the workers said they thought they were getting more exercise than before, although they were exerting the same energy. But they had lost weight and body fat and developed lower blood pressure.

In the new study, which was published in Health Psychology, the researchers looked at two federal health databases. They analyzed over 60,000 participants who had answered questions about how much exercise they felt they were getting compared with others their age and tracked their physical activity using accelerometers.

Using data that showed whether and when the participants died, the researchers found a strong correlation between dying early and believing that one was inactive, even if the data showed they were getting as much exercise as others in that age group.

Of course, this study simply showed a correlation; it can’t prove that beliefs directly shorten or expand a lifetime.

But if the way we think can change our view of the world, it can only be beneficial to view short walks to work or climbing a set of stairs inside a building as moments of exercise to be celebrated.