East's wife, Claire, brought their newborn girl along to one of his training sessions at Crystal Palace recently, and every time he passed her he started to break out in laughter. "I was cracking up," he recalled. "I had to get Claire to turn her the other way."
Olivia will have to settle for a glimpse of daddy on the television today as he sets out in the opening heats of an event rendered intriguingly open with the absence of the Olympic gold and silver medallists of last year - the current champion Hicham El Guerrouj, who has had a virus, and Bernard Lagat, who is ineligible while transferring citizenship from Kenya to the United States.
Although East is only 12th in this season's world rankings, his proven status as a true racer - a capacity which famously earned him that Commonwealth title in Manchester three years ago - offers the possibility of further tangible reward in the Finnish capital.
Sixth place in the Olympic final last year indicated East's world-class status, but since then the 27-year-old former shoe salesman from Portsmouth has been suffering with an injury - the first serious one of his career - which caused him to miss virtually an entire winter training programme. The affliction, which began in October last year, was iliotibial band friction syndrome, a kind of repetitive stress injury affecting the knee. Its cause was unclear - but East junior was in the frame.
"I was doing the same mileage as usual, but Olivia had just been born and I started to spend a lot of time picking her up in the carry-cot," East said. "After a while it does put a strain on your body, because you always seem to be contorted."
East consequently began to be slightly less of a hands-on father, but when the problem persisted to the point where he could not put weight on his bad leg he took what he describes as "a drastic measure" - an epidural injection involving 15 needles.
Thankfully, this scary procedure - which went horrifically wrong for the 400m runner Tim Benjamin shortly afterwards - proved effective, and East has made rapid progress since returning to racing last month at the Norwich Union world trials, where he finished third.
His performance in finishing third at the Crystal Palace Grand Prix meeting just over a fortnight ago in a time of 3min 33.32sec, his second fastest ever behind the 3:32.37 he set last year, convinced him that he was back in top racing shape. Good news for a British team whose medal shots look distinctly sparse here.
East studiously avoids getting involved in lofty predictions. He is concerned simply to use the experience he has gained in the past three years to move efficiently through the rounds in an event which still contains a host of dangerous rivals such as the current world rankings leader Rashid Ramzi, Qatar's adopted Moroccan, and his team-mate, the adopted Kenyan Daham Najim Bashir.
This season has been a heartening one for British 1500m racing, with Nick McCormick, the Morpeth Harrier, winning the AAA title and then taking a staggering 15 seconds off his mile best in Oslo with a time of 3:52.02. Andrew Baddeley also came to prominence by finishing second behind McCormick at the trials, although he narrowly failed to qualify for Helsinki.
East, McCormick and Baddeley may still be a far cry from Sebastian Coe, Steve Ovett and Steve Cram, but the signs of improvement are hugely encouraging after so many years when the British middle-distance scene has been so relatively moribund.
"What Coe, Cram and Ovett did was fantastic, but it's a long time ago now," East said. "Ultimately it's an individual sport, and I need to concentrate on myself now. It's been hard being away from Claire and the little one for this time - but I have a job to do."
Given that he is attempting to edge into the medal zone with a mixture of ability and determination, East could hardly have a better coach than Mark Rowland, whose feat in breaking the Kenyan domination of the Olympic 3000m steeplechase to earn a bronze medal at the 1988 Seoul Games was one of the great unsung achievements in British athletics.
Two years ago in Paris another Rowland athlete, Hayley Tullett, achieved an unexpected bronze in the 1500m. The same again would do nicely for East.
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