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
Avon and Somerset Police have released a set of photos showing the damage that has been caused to a number of vehicles by arson attacks.
Police and fire crew have been dealing with a large fire at a derelict pub in Falmouth overnight.
Bob has the forecast for Devon, Cornwall, Dorset and Somerset