That's because he still considers running is what defines him. As he puts it: "I was a runner first – my inner spirit drove me to become as good as I could be."
Yet despite his considerable competive achievements, and a BBC commentary career now in its 30th year, history will perhaps judge Foster's defining feature to be the UK-wide race series launched through his company, Nova International.
Last week, Glasgow Life announced they were in partnership, with the aim of enhancing the Great Scottish Run and BUPA Great Women's 10km.
It's excellent news.
Once a chemistry teacher, Foster may be the catalyst for explosive redevelopment, hammering home lessons which date back to when Glasgow threatened to rival the London Marathon.
Glasgow had an elite race with just 63 starters in 1979 (you had to have run under three hours) but the first mass participation Glasgow marathon in 1982 had more starters than London had the previous year.
All this stalled due to a reluctance to engage in significant appearance fees and prize money, but signing with Nova has consigned that era to the past.
"They hardly paid appearance fees at all for many years," acknowledged Foster, "but that was in the amateur days. These are professional athletes now. As far as I am concerned, the best athletes in the world should be involved in Glasgow over the next five years.
"Glasgow should be among the world's leading athletics events. I have spoken to the BBC, and if they are prepared to work with us, we can build this from a major national event into a world-class international one."
He has already spoken to the sport's most prolific record-breaker, Haile Gebrselassie. "He hasn't agreed yet, but will have a look at it," adds Foster. "It's one of my ambitions to bring him to run in Glasgow."
The Ethiopian has a fine sense of history, and Foster hopes he can be seduced by a Scottish tradition. "More distance records were set in Glasgow than any other city in Britain," he says persuasively. In one Ibrox race alone (in 1904) Alf Shrubb set eight, from six to 11 miles and one hour. His 10-mile world mark survived for 24 years, and his one-hour time remained the UK best for 49.
The two Glasgow events enjoy a combined annual entry of more than 33,000, but the bar will be raised by harnessing the expertise of Nova, who organise Britain's biggest mass participation event.
Councillor Archie Graham, chair of Glasgow Life and executive member for the Commonwealth Games, said: "With their experience we can take these events to the next level." He hopes it will also promote physical activity lifestyle benefits.
The Great North Run, the world's biggest half marathon – which Foster launched in 1981 – attracts 54,000 entries annually.
The millionth runner will pass under the finish gantry next year – beating the London Marathon to that particular milestone. Indeed, with TV backing, I believe Glasgow has the potential to match the Tyneside race.
The "Great Run" series also embraces events in Manchester, Portsmouth, Sheffield and Edinburgh and almost every UK endurance runner of recent decades served an apprenticeship in them.
The Bank of Scotland Great Scottish Run already is bigger than in the 1980s. Nearly 21,000 signed up in 2009, and there were 23,386 last year, with a record 19,981 finishers.
Yet it is still mainly of national appeal. Foster started from scratch with the Great Manchester Run after the 2002 Commonwealth Games. "We've built it from nothing to 40,000 in 10 years," he told me.
"Glasgow already is the biggest race in Scotland and there's no reason why we can't make it a world-class one. We have a country as opposed to a city, and it can be part of the Home-Coming celebrations – it should be part of the attraction for the diaspora.
"We have a database which reaches 1.5m people all round the UK, and internationally as well, so we will be making them aware of the event. The GNR has entries from every postcode in the UK. We have that ambition for the Great Scottish Run.
"Glasgow is a bigger city than Newcastle, a bigger area than Manchester, and bigger than Portsmouth. It should eventually be one of the world's leading events. It might take five, seven, or 10 years, but that's our ambition." It will also underpin the BUPA women's 10k as Britain's biggest women-only race.
The Glasgow spectacular was outstandingly steered from its inception as the Scottish People's Marathon in 1982 by the late Bob Dalglish, but the city baulked at appearance fees and prize money to attract elite world-class athletes which would have guaranteed TV exposure. The sport was slowly and painfully nudging towards professionalism, but Dalglish, as a national and international athletics official, must have felt he was walking a tightrope.
Foster made his international debut at the 1970 Commonwealth Games in Edinburgh. He was 10k favourite at the 1976 Olympics, "but I didn't run one of my best races. It was only bronze, but because it was the only athletics medal, it had a golden tinge to it by the end of the week."
He still runs up to four miles, three or four times a week. He uses a training app for the GNR. "But I refuse to tell anyone – anyone – how slow I am . . . The best place in life is on the track, doing it. The second best is organising events people do. But if I had the choice – where would I rather have been on the night of Mo Farah's 10,000 metres final? Down there on the track."
Mass participation's field of dreams already owe a debt to Foster. Glasgow may yet do so.
n Entry for the Bank of Scotland Great Scottish Run: www.greatscottishrun.com
n Bupa Great Women's 10km: www.greatrun.org