Rain or shine, at 5.30am Clair Heaviside leaves her Peak District home, dons a head torch and gloves and runs the equivalent of a half marathon to her office in Manchester. The founder and creative director of digital marketing agency Serotonin makes the early departure four times a week, though sometimes runs half the distance and travels the rest on the train. “It depends on the training block I am in. The important thing is — I always run.”

In the winter, Google DeepMind researcher Pablo Samuel Castro wakes up at 4.30am, sometimes to -20C temperatures, and skis cross-country from Ottawa for up to 40 minutes before boarding a train to Montreal. He keeps to snow flattened by walkers. “I can slide more and get up some speed,” he says. When there is not enough snow he tends to walk; in summer, he bikes.

The perk for Castro is to “get my fitness in while also listening to a podcast or mulling over a research problem”. Heaviside says her morning run is part of her ultra marathon training and sets her up “mentally and physically”. After washing and changing, she has an hour or so of “quiet work before anyone else gets in”.