According to Official Guinness Records,
The greatest distance run on a treadmill in one week is 827.16 km (513.97 miles) and was achieved by Marcio Villar (Brazil) at the Américas Shopping in Rio de Janeiro, Brazil, from 28 June to 4 July 2015.Marcio is a dedicated ultramarathon runner and motivational speaker. He began running in his thirties as a way to lose weight and quickly became passionate about ultramarathons.
For a complete list of 2015 records, please visit 2015 Guinness Records in Brazil.