I HAVE a birthday next week. Not a big one that ends in a zero, but a number that takes me significantly closer to 50 than 40, which feels like something of a watershed moment in this journey called life.

I know there are those who view each trip around the sun with the same dread as visiting the dentist for root canal treatment or being trapped in a room and forced to watch Mrs Brown’s Boys against their will.

Me? I love birthdays and have always been a firm subscriber to the “don’t regret growing older, it’s a privilege denied to many” school of thought.

Curiously, though, lately I have found myself pondering the tipping point between “older” and “old”. The juncture at which “she fell” became “she had a wee fall”. Or when you find yourself saying about almost every fashion trend: “Ah, I remember those first time around …”

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It is seeing someone sporting an “Oodie” (a wearable hooded blanket) and having a flashback to your early twenties when, after stumbling home drunk from the pub, you turned on QVC and saw your first “Slanket” (a blanket with sleeves). 

And being so enraptured by its spellbinding practicality that you immediately called up the telephone number on the screen and bought one (yep, this was pre-internet).

In further thought-provoking nostalgia, the other day I was perusing a Christmas gift guide on the website of a glossy women’s magazine. The first thing to catch my eye was a SodaStream. Then came the soul-jarring jolt of realisation that I was looking at the section for “grandparents”.

In its heyday, owning a SodaStream was the stuff of major bragging rights. Proper Keeping Up With The Joneses territory. The 1980s equivalent of a Ninja air fryer today.

Yet, seeing that SodaStream next to a Jo Malone lavender diffuser, Cath Kidston garden trowel and a “Welcome to Gran & Grandpa’s House” doormat, the penny dropped. It was akin to me giving my grandparents a similarly hallowed gadget: the Teasmade.

A little speech bubble popped up in my head. “Am I old?” But here’s the thing, I don’t think I am. And nor do I think I am in denial about it either.

Sure, middle age comes with a growing clutch of everyday indignities, often involving bizarre micro-injuries: a limp (my sock touched my toe funny); a crick in the neck (I sneezed while trying to unlock the front door); heartburn (looking in the vague direction of spicy chillies in the supermarket).

But the truth is, I don't feel like I’m on a slippery slope where my best years are behind me. In fact - joking aside - I’m in far better shape now than I was in my mid-thirties.

Hear me out. Studies have shown that feeling younger than your actual years may be good for your health: what is described as “subjective age” as opposed to “chronological age”.

Recent research led by Markus Wettstein, a psychologist at Humboldt University of Berlin, analysed data from the German Ageing Survey which, since 1996, has tracked almost 15,000 adults, aged between 40 and 85.

Wettstein and his colleagues found that older adults who feel young at heart are not only likely to live longer, but may also have more life satisfaction, a lower dementia risk, reduced depression symptoms and better overall wellbeing.

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Physical activity and cutting back stress were also cited as having a positive long-term effect on subjective age.

None of us knows what the future holds, but down the line I want to be able to get in and out of an armchair unassisted, ditto going to the loo or being able to dress myself.

I’ve seen a slew of social media videos where women of all shapes and sizes are asked what they are training for. They each give the same answer: “my old lady body”.

We’re talking bone density, strong muscles, a healthy heart, good balance and functional independence. Those are my kind of life goals.