Mowlem has a tremendous fitness ethic. He took part in the London Marathon, completing the distance, as part of a charity fundraiser by the British Racing Drivers Club in 2010. The BRDC effort raised eighty thousand pounds. Mowlem's effort was all the more remarkable as his training was limited by a torn Achilles tendon suffered three months earlier. Mowlem was hurt while playing soccer. He ran the London Marathon again in 2011 lowering his personal best to the 3hr 45m mark.