BARCELONA (Reuters)

When Mike Humphreys finished his 42 kilometre (26.1 miles) run in Barcelona on Friday, he walked to his van, took a quick shower and then drove 200 kilometres to Andorra, where he ran the same distance the next day.

The marathon-length runs were just the beginning of a challenge Humphreys has set himself to complete this month: running 30 marathons in 30 days in 30 countries.

"I'm going to be honest: this challenge is crazy. My family has tried to persuade me out of it so many times," he told Reuters from his van in Barcelona.

They told him to spread the runs out over six months or hire a support crew, but he insisted on doing it alone and within a shorter time frame.

The 33-year-old Briton, who records his whereabouts on social networks, is raising funds for research into motor neurone disease, an uncommon condition that affects the brain and spinal cord. It has no cure and eventually causes death.

On his fifth day, after further runs in Cannes, France and Monaco, his page on the online charity fundraising platform GoFundMe showed he had raised 7,790 pounds ($10,187).

Humphreys decided to act after his friend Craig Eskrett was diagnosed with the disease.

Another friend, Carl Giblin, died from it in 2013 and he wanted to do something to stop him feeling helpless.

"If I can raise awareness we can get more funding and hopefully there's a cure or there's treatments around the corner," he said.