Jamie will be running across Canada during part of their winter, so will encounter Arctic temperatures he has never experienced before.
We took him to Gloucerstershire University's Sport & Exercise Laboratory where they have a chamber in which the temperature can be lowered to minus 20C.
More top news
A family who spent a fortune putting up charity Christmas lights outside their home are devastated after vandals damaged the display.
The players spent the afternoon in the children's playroom and the teenage unit at the hospital.
A supersonic car designed to reach speeds of 1000mph will try out the race track where it hopes to break the world land speed record.