BBC Breakfast presenter Louise Minchin, 51, challenged herself to the gruelling Breca Swimrun last weekend, which consisted of nine swims and nine runs.
The host took part in the race to raise money for mental health charity, Mind.
The following day, she told fans she had snuck her trainers into the studio as her toes were still sore.
Louise shared a picture of a pair of silver trainers hidden under a black cover in view of her 34,000 followers.
She wrote: “Good morning, sneaking my trainers on @bbcbreakfast as I have very sore toes post @brecaswimrun!! Ouch ouchy ouch.”
Many of the presenter’s fans flocked to her page to comment.
One user wrote: “Bless your poor feet Lou!”
A second commented: “What an amazing effort though!” while another added: “They are gorgeous and still glam!”
Louise also shared a lengthy post about her experience, admitting she had been in tears.
Dan Walker’s co-star shared a picture of herself alongside a companion enjoying a large pizza.
She wrote: “Oh my goodness that was a tough race @brecaswimrun #coniston 9 x swims and at least 9 runs through stunning landscape with fantastic volunteers 48k on the clock!”
“Thank you brilliant coach/friend @time2trainclaire for coping with the copious tears, keeping me safe when I was very cold and cajoling me round without you, I would have given up.
“#teamwork I will try to hobble back to the @bbcbreakfast tomorrow!!”
Ahead of the race, Louise revealed the challenge was her last of the year.
In view of her 167,000 Twitter followers, she wrote: “So my last race of this year is suitably epic 45k of swimming and running @BrecaSwimrun #coniston and I will be mightily glad when I see this again.
“Just hoping I can keep up with my teammate and brilliant coach @Time2TrainFit.”
Back in August, the amateur triathlete completed the Norseman triathlon.
Louise Minchin said she was “broken” after what she described as her “toughest challenge yet”.
The intense challenge consisted of a 2.5-mile swim, a 112-mile bike ride, followed by a marathon, all taking place in Norway.
BBC Breakfast airs weekdays from 6am on BBC One.
