Your Mind Is Rewriting Your Body

In 2007, Alia Crum recruited 84 hotel housekeepers for a study.

Their job is physically demanding. Making beds, pushing carts, scrubbing bathrooms. On their feet all day. By any objective measure, they're getting exercise.

Most of them didn't think so. When surveyed, the majority said they didn't exercise regularly. Some said they got no exercise at all.

Crum split them into two groups.

One group got informed. She showed them a poster explaining that their daily work met the Surgeon General's recommendations for physical activity. She told them exactly how many calories each task burned: making a bed, vacuuming a room, changing sheets. She told them their job was exercise.

The other group heard nothing new. Same job, same routine, no new information.

Four weeks later, Crum came back and measured them.

The informed group had lost weight. Lower blood pressure. Lower body mass index. Compared to the control group, who worked the same job for the same four weeks and changed nothing. Zero difference in their actual behavior. The only thing that changed was what they believed about what they were doing.

Their bodies responded to the belief. Not the activity.

This is what makes the finding so hard to dismiss. You'd expect a thought to change how you feel. But it changed how much they weighed. It changed their blood pressure. Those aren't mental outcomes. Those are measurable numbers on a scale and a cuff.

The belief that you're exercising, when you actually are, produces different physical results than doing the same work without that belief.

Which means the story you tell yourself about your body, your self, your life, your values, your relationships, isn't just in your head. It manifests into your reality.

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Part of the Alia Crum Studies series. Previous: Your Body Believes What You Tell It. Next: How Your Thoughts Become Physical Events.