Not all sports will deliver new personal bests. Some come with greater chance of injury, such as team sports and ball games. But that shouldn’t deter you, though, especially if the weekly five-a-side means more than a kickabout. “Men in midlife often report feeling like they have reduced social support or social circle, and therefore sport can provide a social outlet,” says Dr Henry Blake, a lecturer at the University of South Australia whose research into sports participation among middle-aged men identified a positive relationship between team sport and individual well-being. “It is simply important to appreciate the risks and weigh them up.”

The losses are real in midlife. Your metabolism slows by five per cent every decade from your forties. Your cardiovascular endurance drops one per cent every year. But it is possible to fight back.

A study by the University of Texas Southwestern Medical School found that over 50s participants in a six-month exercise programme lost weight and lowered their blood pressure, while their heart’s ability to pump blood returned to levels experienced in their twenties. It’s not a breeze, says Askwith, who, at 64, runs 30 miles a week, but the rewards are great. “It will always be an uphill struggle, keeping going, but it’s worth it, and the aches and pains and other discouragements are a price worth paying.”

In your twenties, you could get away with doing any exercise unprepared and come out relatively unscathed. That’s not the case in middle age, where poor technique or doing too much could result in serious setbacks.

“The key thing to remember is that you’re not 20 anymore,” says Mr Jason Smith, AKA 53-year-old personal trainer @fitinmidlife. “Your body will be slower and weaker, and you should adapt the exercises to take that into account. Don’t let your ego tell you how much weight to lift. It’s far more important to perform the exercise at a good tempo and with control and good form than it is to strain every muscle in your body to achieve a one-rep max personal best.”

We lose between one and three per cent of muscle mass every decade from our fifties. The good news is it is possible to resist, and you don’t have to have the resources of a buff billionaire to do it. “We can all reduce or even reverse the impact of muscle mass loss through strength training, which becomes more important as we age,” Smith says.

Strength training can mean gym weights, bodyweight exercises or a gruelling gardening session. Lifting something other than the TV remote will improve your life. “Changing our body composition to favour muscle gives us the energy we need to live a full life in our middle years and beyond,” Smith says.

Smith turned his life around at 49, when, faced with high cholesterol, hypertension and obesity, he hit the gym. He was motivated by keeping up with his young son rather than aesthetics, but his impressive physical transformation illustrates what is possible.

“Don’t let anyone tell you that you cannot achieve the body you want in midlife,” says Smith, now 53 and rocking a six-pack. “Many quit on their fitness because of impatience, and before the changes happen. Be prepared for the long haul as it will take some time, but it will happen.”

There’s no sport that the research suggests is better than others for those in midlife. Doing any sport is better than none, Blake says, so pick one you enjoy. “It is important for men to consider what sport they may enjoy participating in as this is a strong predictor for continued engagement.” Then, keep going with it.

Whichever you choose, it’s good to remember that it’s better than the alternative. “Being an older runner is tough,” Askwith says. “But it beats being an ex-runner.”