Treadmills desks can be built at home as long as you have a treadmill. Sharyn Morrow/Wikimedia Commons via Flickr hide caption

itoggle caption Sharyn Morrow/Wikimedia Commons via Flickr

Are BPA-free bottles really safer than the ones that are chock-full of bisphenol A? Good luck trying to find out. David McNew/Getty hide caption

itoggle caption David McNew/Getty

Orthopedist Popi Gianakouras helps 45-year-old Bob Rothaker with physical therapy to treat his sore shoulder. Richard Knox/NPR hide caption

itoggle caption Richard Knox/NPR

Most Americans spend the majority of their waking hours sitting still in front of a computer or television. iStockphoto.com hide caption

itoggle caption iStockphoto.com