You're absolutely correct. Both are important.
Here is a very important incentive to increase physical activity. It has actually been raised indirectly here by a couple of folks. The issue actually relates to shovel-smart infrastructure investments. This was mentioned a little earlier.
Currently in Canada, we have a coalition that's asking for investments in active transportation infrastructure. This means sidewalks, bike lanes, and bike paths. This will help people commute to work more easily by having access to public transit rather than having to depend on cars all the time. They'll be able to walk to the store, etc. What does this do? It reduces greenhouse gas emissions, reduces air pollution, creates jobs, and makes people healthier and therefore more productive.
A very important incentive is to invest in shovel-smart infrastructure that promotes active living. That's much preferable to the road to nowhere, which has no return on investment other than creating jobs. We've got to create jobs, but we also have to be smart with our infrastructure investments.