Cancer Research UK generates 20 per cent of its income doing it; Marie Curie Cancer Care gets more than 8,000 people each year doing it; and Crisis is preparing to do it next week.
We're talking about fundraising from running events, something that has become increasingly lucrative over the past 10 years.
The sums are impressive: Race for Life, Cancer Research UK's women-only 5k event, which takes place at 280 venues, expects to raise £60m this year, compared with £27m two years ago and £1.25m 10 years ago. The sum even beats the London Marathon, which raises £41.5m a year for those charities lucky enough to get places. So what is causing the charity running explosion, and can it last?
One of the main reasons for the boom is that running appeals to individuals and companies as well as charities. "People are becoming increasingly aware of health and fitness, so they are more likely to take up running," says Gwen Pearson, chair of the Event Managers Forum, an informal network of fundraisers.
"Companies want staff to be active, and keeping them fit is part of their corporate social responsibility policies." Tesco, investment bank JP Morgan and sports marketing agency Nova International are among the prominent corporate supporters of running events.
Real people with real stories
Louise Holland, national events director at Cancer Research UK, attributes Race for Life's popularity to its simplicity. "We ask people to run because, as a cancer charity, we want them to get active," she says. "It's not time-consuming, it's not competitive and it is emotionally engaging."
Marathon world record holder Paula Radcliffe launched this year's Race for Life series on 2 May in Battersea, south London, but Holland says celebrities are not "key drivers" to the event's success. "It's about real people with real stories of cancer," she says. The series reaches its high point on Sunday, with 24 races at 16 venues.
Around 80 staff at Cancer Research UK work on Race for Life full time. The charity also raises £5m from running events staged by other organisations and £3m from a series of 10k races for both genders it stages at stately homes. The number of stately home races has grown from three to 32 in three years. Is there no end to running fever?
"There has been a boom and it's becoming more competitive," says Holland. "The market is getting saturated, but there are still lots of charities putting on 5ks and 10ks."
Sarah Walker, community and events fundraising manager at homelessness charity Crisis, agrees things are getting tougher. "Running is reaching its peak," she says. "There are only so many events people can take part in."
Around 2,000 people will take part in Crisis' annual Square Mile Run on Thursday next week. The race costs £30,000 to organise, which is mainly covered by sponsors Threadneedle Investments, and yields £150,000.
It is a relatively small race that requires considerable effort: 100 volunteers have to be mobilised for duties such as marshalling. Nevertheless, Walker calls it "extremely cost-effective". Crisis also gets £50,000 from its 25 guaranteed entries in the London Marathon and £10,000 from its team of runners at the Great North Run.
The Great North Run is the country's most popular race. Around 50,000 people, from 80,000 that apply, participate. It is part of the Bupa Great Run Series, which has adopted Marie Curie as its charity of the year for the past two years.
Last year, the cancer charity received £1.1m from the efforts of its runners in the Great North, Great South, Great Manchester and Great Edinburgh races.
This year, races in Sheffield and Cardiff have been added to the programme. "Pulling in £1.1m was astronomical," says Pat Darling, events manager for special projects at Marie Curie. "We are waiting to see how much we get this year," she says.
The races enhance awareness as well as fundraising. Marie Curie brands everything running-related with its logo. "We want to establish the charity as a running brand," Darling adds.
She says that running has changed over the past 10 years. "You never used to get hours of television coverage and celebrities involved," she says. "The average person in a supermarket would never have dreamed of running in the street unless they joined a running club. It's totally different now. With the correct training, anyone can do a half-marathon."
With London 2012 approaching, and obesity concerns growing, charity races could become more popular. And the rise of online giving will make collecting sponsorship easier. So expect an ever fiercer race among charities to generate money from running.