It’s considered one of the hardest athletic challenges. 21 day-long stages covering around 3,500 kilometres (2,200 miles) - it’s the Tour De France.
A Tour de France rider will burn enough calories during a six-hour mountain stage to fuel an average person's activity for two to four days. So how do these athletes compete day in, day out?
On this episode of the Oxford Sparks Big Questions podcast we are asking the question: Why are athletes using ketones?