One recent study, published in the journal Heart, said people in their 70s who did 20 to 40 minutes’ moderate to vigorous exercise a day had significantly lower rates of heart disease than those who were inactive. Meanwhile another recent study, looking at adults aged over 55, who showed no signs of dementia, reported that those who took part in three 50-minute sessions of moderate physical activity a week, such as brisk walking, helped preserve what is called episodic memory, the ability to recall past personal events.

For one friend, David Ingram, 72, who had a heart attack and triple bypass surgery at 65, owing to a genetic heart condition, the fact that he was already fit through regular gym exercise, according to his consultant, almost certainly saved his life. Since recovery he has lost 20lb by being more careful with his diet, but also takes part in a long-term cardio rehab programme, which involves ongoing monitoring, working with weights and cardiovascular activity on the treadmill. His treadmill is parked permanently in his living room.

“I love exercise,” he says. “I know it’s good for me and if I do it first thing it sets me up for the day. It also helps a lot with anxiety. While I’m on the treadmill I listen to podcasts or music. At the moment I’m working my way through all the old episodes of Desert Island Discs. Yes I’m knackered at the end of a session, but after 20 minutes I’m fully recovered. And yes, it’s a challenge – you are always pushing up against your age – but then I love a challenge, too.”

For another pal, ITC consultant Graham Zabel, 59, keeping fit is an intrinsic part of life, not a begrudged add-on. He stretches a few times, touching his toes, in the shower every morning, walks the dog and, if heading for the office, which he does twice a week, cycles the approximately eight miles each way. And he’s a fair-weather golfer. But his main go-to exercise is karate twice a week for 90-minute sessions, and an extra Sunday session teaching a bunch of children, which he loves. “Karate involves technique, speed and strength; it’s also great for memory as you have to learn the kata [motion sequences and forms] and every week you have to practice a different set of forms.

Zabel has successfully passed on his love of sport to his children, now 19 and 22. The youngest, a boy, is a gym fanatic and loves football; his daughter did taekwondo from a young age, they did karate together for a while and she also cycles everywhere. It’s also important, Zabel believes, to have a partner with a similar attitude to sport and exercise. “Fortunately I do,” he says. “We often go walking together at weekends.”

Not everyone is as motivated as Ingram and Zabel. But for all those exhausted grandparents out there, trying to keep up with the kids, there’s an intriguing new theory called “the active grandparent hypothesis” to encourage you to get moving. Grandparents, according to a team of Harvard researchers, have a key role in intergenerational survival. If you get more exercise you won’t just be aligning your body with evolutionary history, you’ll be doing yourself and the grandkids a big favour by staying alive.

Much of the evidence is based on one of the few remaining hunter-gatherer tribes, the Hadza of northern Tanzania, who spend four to six hours a day engaging in moderate to vigorous activity, as is likely their ancient ancestors did, too. While older westerners often head for the couch, the Hadza keep on going. Hadza grandmothers, especially, continue to forage while their daughters spend time looking after their own children. The grub gathered by grandma helps sustain the family.

By linking this back to the behaviour of older people in the West, the report suggests that old age in humans likely evolved with a highly active lifestyle. Regular exercise keeps us lean and fit, ergo it diverts energy away from the harmful visceral fat. It also kick-starts the wear and repair and maintenance mechanism, which includes the muscles, cartilage and the internal antioxidant system. This doesn’t only get us back to where we were but improves our health. The message is clear: even if you can’t be bothered for yourself, do it for your grandkids, and everyone will benefit.

Getting started

If you are starting from physical activity close to zero over a number of years, it makes sense to begin cautiously. Government guidelines suggest you aim gradually towards 150 minutes of moderate-intensity exercise a week, such as swimming, cycling, brisk walking or 75 minutes minimum of vigorous activity such as running, sport, or even going up and down stairs. You could also do a combination of the two. It also suggests strength building of at least two sessions a week, which could range from gym workouts to carrying heavy bags home from shopping or doing yoga. Then, in addition, to help with balance, an exercise such as tai chi or dancing.

But the idea that the type of exercise we need to do should change as we age is something of a myth, says Pitt-Brooke. It’s not about your age; the basics of building muscular and cardiovascular strength, and maintaining flexibility, apply at every age. “What may need adapting,” she says, “is the intensity with which you exercise to meet the challenges of different decades and your capabilities.” In your 50s, the challenges are most likely early signs of joint discomfort and a tendency to put on a bit of weight, depending on your lifestyle. By your 60s, especially for women, there’s the challenge of bone-density loss, which again requires adequate weight-bearing exercise. Walking, yes, jogging or running if you’re up to it, tennis, climbing lots of stairs and dancing are all good. Plus resistance exercises with weights. For some, blood pressure creeps up and you may become pre-diabetic or diabetic. Then, by your 70s, there’s significant muscle deficit, which influences balance and reaction times. Which is where I’m heading right now if I don’t take further action.

A good example of adapting a posture to your age, if you’re out of practice, suggests Pitt-Brooke, might be the way you approach a squat. For a 50-something it might be manageable to start with an air squat; a 60-something might need something like a stool, lower than the average chair; an elderly person may need to start pushing up from a chair with arms. But the principle of squatting to improve strength in the glutes, the hip flexors and the quadriceps remains exactly the same. And of course a super-fit 70-something may be a good deal stronger than a very overweight couch potato in his or her 50s.

The way forward

I’ve decided to take further action to build my strength and improve my balance. The walking I do is a pleasure. For some it may help to go with a friend or walk with a group. I enjoy that, too, but am happy to walk alone. It works wonders on my stress levels, frees my imagination for when I write fiction and clears my head, so I can better work through problems that are niggling me. The Pilates stays on the agenda because it definitely helps my general stiffness and contributes, if in a small measure, to strength. Pitt-Brooke reckons that a programme of progressive general muscle strengthening, which I will kick off with a series of once-weekly online classes with a trainer, while promising to practice what I’m taught a couple of times a week between sessions, could boost my functional strength, within three months, by up to 30 per cent. And if I keep at it on my own, say three times a week following the one-to-ones, by as much as 50 per cent over a six-month period. That’s way too enticing a prospect to miss out on, even though I admit it does feel like it’s going to be hard to keep it going.

I’ve also taken to standing on one leg twice a day while I brush my teeth to improve my balance. I feel a bit daft, like a stork with a tremor. But it’s a small price to pay if I can get through the next decade without falling flat on my face.

Tips for over-50s

The importance of balance

Falls in later life can have devastating consequences. As Dr Lucy Pollock, author of the excellent The Book About Getting Older (for people who don’t want to talk about it), published by Penguin, explains: “People who exercise are less likely to fall. People who have never exercised, and start exercising, become less likely to fall. People who have fallen, and then take exercise, are less likely to fall again. We need to get moving.” Standing on one leg is a good place to start.

Strength-work basics

All work to improve muscle strength, advises chartered physiotherapist Judith Pitt-Brooke, involves squatting, stepping, pushing, pulling and abdominal crunching, using weights that gradually get heavier as you progress. You don’t have to do this in a gym, but if you’re starting from scratch it’s best to get professional advice from a trainer to get you going. Check out bridge4studio.com for programmes aimed at the 40-plus and which can be accessed online.

If you’re gym-averse

One of the few upsides of the pandemic has been the mushrooming of online classes. From Pilates, yoga and Zumba to Joe Wicks’s Home Workouts for Seniors, and aerobics with Rosemary Conley, you really can get fit from the comfort of your own home.