SOMETIMES when you read newspapers, you feel as if pensioners are in a permanent state of decrepitude.

If they are not blocking NHS wards with their multiple ailments, they are worryingly prone to Alzheimer's or stuck in their homes, fearing to go outside at the first hint of ice or snow in case their feeble limbs collapse into an instant leg-break.

So at first sight, when you read that Celtic Connections in Glasgow at the weekend was having an evening with Jimmie Macgregor and friends, your first thought might have been: "That Jimmie Macgregor? The one who used to be in a folk duo with Robin Hall? Is he still performing? Or is it a youngster with the same name? Or is it a memorial concert of his music with Jimmie in a wheelchair at the side of the stage?" Well, fear not. Jimmie is still singing, playing guitar, and just generally being as impish as ever at the age of 84 as he did decades ago. And curses, he still even has a fine head of hair men half his age would envy, even if it is as white as the Campsies after a snowstorm.

If you live in Glasgow's west end you may be aware that Jimmie is still a familiar face even though he has been collecting his pension for nearly 20 years. You might still see him chatting to friends in the local pubs, such as The Doublet, although he is more likely to nurse the one whisky for an hour or two rather than gulp it down. The Oran Mor lunchtime play will usually see Jimmie in the audience every week. And his love of Scotland's hills is ongoing, years after he found a new audience on Radio Scotland and then television, trekking the West Highland Way or Alaska in engaging travelogues years before Michael Portillo boarded a train with an old railway guide.

Before he went on stage on Sunday I chatted with Jimmie who explained: "I may have really pushed too hard on the last hillwalk. I did in my knee and an Achilles' tendon." But it was never going to stop the concert taking place. Says Jimmie: "I don't need to do it for the money. But I just love it so much. I like being on stage."

His voice still has the clarity and warmth of years ago. He might change the odd note to ensure a song is still within his range, but to my ear he sounds the same Jimmie Macgregor. You want to ask him what his secret of keeping so young is. But he's too busy to chat too much about it, always dashing off to something else. Which in itself is part of the reason he keeps so young. For as he once put it: "Some people are dead long before they take their last breath.

"I still want to explore parts of ­Scotland in what time I have left. Every time you turn a corner there's another loch or mountain. There's no excuse for ever getting bored."

The previous time I saw Jimmie perform was an anniversary concert in the old fruitmarket in Glasgow to mark the anniversary of the UCS shipyard work-in, when the audience was a little on the mature side. As Jimmie told them, in a break between songs: "Ronnie Scott of Ronnie Scott's jazz club once said that you can look young by associating with old people. So thanks very much for coming along tonight."

Music has played a big part in Jimmie's life since childhood in Springburn, Glasgow, when house parties were common in the pre-television age, and everyone had their own party piece. He went to Glasgow School of Art after his National Service because of his skill in drawing, but music was his obsession, and he started hitch-hiking to London to perform, finally moving there in 1956 "with a guitar, £60 and a brass neck", scratching a living playing in various bands, before being asked to sing Burns songs on television's Tonight programme with fellow performer Robin Hall. They didn't know any Burns songs, and learnt one on the way there in a taxi. The Tonight show asked them to stay for the next four years.

Then Jimmie and Robin toured as well before the double-act split up.

As Jimmie recalls: "I was a fairly heroic drinker with Robin but I've virtually given it up. You have to be a wee bit careful. But I was always physically very active, hillwalking a lot of the time. Robin didn't have that compensation."

In fact Jimmie, who likes a good tale, once told us about a west end chap called "Jimmie" - yes, same name as himself, who turned up at a female friend's flat with a carry-out. There was no one else there. After being offered a cup of tea he asked her when the others were coming. "I'm sorry Jimmie, the party was last night." She then added the killer line: "And you were there."

So if there is any secret to staying young, it's keeping as active as you can, watching the booze, and simply keeping your curiosity about the world around you, which is why Jimmie still loves to perform, still climbs Scotland's hills, still takes himself out every week to see a new play at Oran Mor, and still even writes letters to the Herald if there is a subject in the news he can shed some light on.

American journalist Doug Larson once wrote that "The ageing process has you firmly in its grasp if you never get the urge to throw a snowball." Jimmie Macgregor, one suspects, is always the first to form a ball in his hands when the snow falls.