When you are looking for people to contact so you can get on national public radio a very helpful tool is to use media directories to aid you in your search.

You can use Bacon's Media Directory. There's both an online version and a book version. That book version is very expensive and weighs a gazillion pounds. So just go to your library and ask your reference librarian. Those are very helpful because they're subject specific and can certainly point you in the right direction very easily. You can also just go to Google.com and type in the words "radio" and "show" and "health" and you can type in "public radio" if you're looking specifically for NPR shows.

You can find more information like this in How to Get Booked on National Public Radio.
http://101publicrelations.com/nationalpublicradio.html?utm_source=prideas&utm_content=npr