Extreme calorie burning!

Five years ago my husband, Mike, walked to the North Pole to raise funds for an African charity. He was part of a 15-or-so strong team of mostly men but also a few women. For the weeks and months prior to the unaided trek, (ie no dogs, no transport) Mike spent many an hour walking around our field with a massive lorry tyre, attached to ropes, harnessed to his waist which he dragged behind him in