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
Becky Watts' uncle speaks exclusively to ITV News following the arrest of two people on suspicion of her alleged kidnap and murder.
The killer serving life for the murder of Jo Yeates has been sentenced to a further 10 months after admitting possessing child abuse images.
Meet the twins from Gloucester who've had to produce their birth certificates to friends in order to prove that they are in fact related.