A Tour de France cyclist has revealed the impact racing has on his legs - and the internet is pretty concerned about it.
Cyclist Pawel Poljanski shared an Instagram photo of his legs, covered in bulging veins, and explained that after 16 stages of racing they "looked a little tired". (Understatement of the century.)
The picture has gained a lot of attention, with people questioning whether it's normal and, indeed, healthy to have such protruding veins.
After the 16th stage of the Tour, Poljanski is ranked 75th in the general classification. There are five more stages to go.
The route, which started in Düsseldorf and ends in Paris,covers a total distance of 3,540 kilometres.
After he shared a photo of his exhausted legs on social media, one commenter said: "That don't look healthy my dude [sic]." Another added: "How are you not dead?"
So, why does this happen?
Increased cardiac output during exercise means that the blood has to circulate faster around the body to get to the muscles.
"It then has to return to the heart quickly for the next round," Dr Helen Webberley, who runs the online healthcare service My Web Doctor service, told HuffPost UK.
"This is usually via the deep veins in the leg, but if the exercise is extreme then there will also be increased flow back through the more superficial veins which could create this type of effect."
Is it dangerous?
Luke Worthington, head of trainer education at Third Space and a Nike ambassador, told HuffPost UK the prominent veins are "just an indication of how lean Poljanski is and also how much blood has been pumped to the working muscles".
He explained: "Most lean athletes will appear to be this vascular - it's made to look more excessive by the amount of muscle mass he carries in his quads."
In terms of pain, Worthington estimates that he would expect Poljanski to have experienced delayed onset muscle soreness (DOMS) the following day, however he added that a conditioned athlete would recover pretty quickly - perhaps even within 24 hours.
He added that ice baths might help reduce inflammation in athletes, as would compression clothing.
"Athletes like this are outliers," he concluded. "They are genetically gifted as well as being highly trained and psychologically prepared to go through the events they do. They shouldn't be taken as markers for general population, in the same way that Usain Bolt or Cristiano Ronaldo shouldn't."
In other words, don't worry too much about Poljanski's legs.