There are sponsored walks and 10K runs a-plenty ahead of Comic Relief’s annual celebrity fund-raiser Sport Relief.
And then there are those that go far above and beyond the call of duty to do something truly spectacular.
Take Davina McCall’s gruelling 500 mile triathalon for example, which will see the presenter travel by foot, bicycle and water to get from Edinburgh to London in just seven days - if she makes it past day three.
The latest leg of the charity trek saw her conquer the width of Lake Windermere from Pullwood to Low Wood, a life-threateningly cold stretch of water which she dived into just one day after completing a 14-hour cycle through an icy rain storm.
Needless to say, the TV personality was already showing early signs of hypothermia after the first day.
“#Davina's had to take an unscheduled stop,” Sports Relief tweeted via its official account.
The yesterday, on the second day, Davina road by bicycle from Seatoller, climbed Scafell Pike and descended to Langdale, before she cycled seven miles to Ambleside.
But on the third day today, the scenes of her limp body being dragged from the waters as she collapses from extreme exhaustion, as seen in the video below, are truly unbelievable:
McCall underwent medical tests amid fears she may have been suffering from hypothermia after battling severe weather.
It was thought that the event would have to be cut short if health professionals deem the risks to her safety too high to continue.
Professor Greg Whyte, the trainer for the Sport Relief challenges, said: “These are the worst weather conditions we've seen on any challenge - it's the worst weather ever.”