The things that scare you are probably not the things that will actually kill you, says the CDC Director. It’s important to accurately assess risk, he advises.

Thomas Frieden: Understanding risk is the most important thing. We fear things that are very unlikely to result in us getting hurt or killed. And we’re way too nonchalant about things that are life and death threats to us. So understanding that if we can get regular physical activity, we will live a lot longer and feel a lot better. And thinking about ways to build that into our lives, we’re probably willing, if we really understood the risk of not getting physical activity, we probably would be willing to make big changes in our lives. But that’s not so clear.

On the other hand, we may fear things irrationally or out of proportion to their level of risk. We’re recently able to measure, for example, minute amounts of radioactive fallout from the nuclear disaster in Japan. We wished those things weren’t in our environment, but they’re being measured in the trillionths of a curie and they are no where near the level of a significant public health concern, and yet, that will get more attention over the coming weeks in all likelihood than things like air quality problems from fossil fuels, which are killing many people in this country or the lack of physical activity, which we can do something about by helping people and fostering activity by making our communities easier to walk, easier to bicycle, encouraging people to take the stairs. Lots of things we can do on a community level and on an individual level to live longer and healthier lives based on a better understanding of risk.