Sleep has not been coming easily for Kariem Hussein since his epic 400m hurdles gold before an ecstatic public last Friday night in the Zurich Letzigrund stadium.
Just as it is impossible to sleep after getting it all wrong it is just as difficult when everything goes right.
Hussein has lost count of the number of times he has viewed his race on video playback. It is almost as though he still has not come to terms with the enormity of what he has done.
Inevitably he is now considering other implications. Given the fact that he is now European champion, what are the chances he can take it much further.
“I know that with a time in the high 48s I cannot be world champion,” he told the Swiss press. “The goal has to be low 48s or a time in the 47 second region.”
Asked by the Swiss newspaper NZZ about his potential, his coach, Flavio Zberg, was more circumspect: “I don’t want to name a time, but he certainly has enough potential to go faster.”
His run of 48.96 was Hussein’s third personal best of the year, meaning he has taken more than six tenths of a second off his pre-season lifetime best.
At 1.91m tall and weighing 76 kilos, his coach says he has an ideal build coupled with a strong will: “The combination makes him an excellent athlete,” says Zberg.
After missing last year’s World Championships through injury, Hussein and Zberg’s big challenge is to nurture his body so that he arrives at the big races fully fit.
Which is probably why his warm-up is unusual in that it involves little running over the hurdles and a lot of massage before he goes out onto the track to race.
“It is something we have developed with his physiotherapist,” explains Zberg. “It is designed to prepare his nervous system for racing.”
He was probably in no condition to compete for his team in the 4x400m heats on Saturday, his legs were still feeling the after effects of his exploits and his coach decided it was better to not run the relay.
But lack of sleep is something he is going to have to get used to because in October the medical student begins his in-house practical in hospital which normally entails long hours on the ward.
The implications are that 2015 will be a low-key year for Hussein before he leaves space to begin his build up to the 2016 Rio Olympic Games.
At the moment, Hussein is determined to finish his studies in 2017 so it seems inevitable that the clash between training and classes will be an ongoing concern.
But for the time being, he can enjoy his gold medal and watch that race a few more times to let it all sink in: “That’s why I came into athletics,” he says, “For moments like Friday.”