“Mens sana in corpore sano” – a healthy mind in a healthy body. This pearl of wisdom from the second century AD, courtesy of the Roman poet Juvenal, shows that as far back as the classical era, people understood very well the benefits of physical exercise, especially when coupled with good nutrition.

Given the enormous leaps in anatomy, physiology, and medicine since then, one might be forgiven for assuming that this generation of humanity would be the fittest in history. Sadly, this does not appear to be the case.

Research from the World Health Organisation this week reveals that almost a third of the world’s population is at risk of developing deadly diseases such as cancer, stroke, dementia, and diabetes due to a lack of exercise. About 1.8 billion people, or 31 percent of adults worldwide, did not meet the recommended levels of physical activity in 2022.

A global target set by the World Health Assembly – a 15 percent reduction in insufficient physical activity between 2010 and 2030 – is widely expected to be missed.

If we assume that most people understand that exercise is a non-negotiable requirement for living a longer, healthier life, why are nearly two billion people failing to do it?

The reasons are many, but the prime among them is the fact that much of modern life relies on work confined to a desk and modes of transport that do not encourage much physical activity.

More than 55 percent of the world’s population – 4.4 billion people – lives in cities.

It is expected that by 2050, that figure will rise to 70 percent. Urban living and changed job requirements have contributed to reduced activity.

Another matter of concern is the bewildering array of changing and often contradictory fitness advice that greets anyone who simply wants to get in shape.

For one month, steady-state cardio will be held up as the best way to lose weight.

The following month, people will be told to switch to high-intensity training instead. Or weightlifting, or exercising first thing in the morning, or Pilates, or any one of a hundred different methods. And that’s leaving aside a similarly overwhelming barrage of nutrition advice.

Some of this is driven by a fitness industry that has a vested interest in selling equipment, gym memberships, and dietary programs to as many people as possible.

Wexer, a Danish digital fitness company, says the industry is growing at a rate of nearly nine percent each year, with a projected market value of $96.6 billion this year.

In addition, Wexer claims, the number of health and fitness club memberships worldwide was thought to reach 230 million last year.

Business is booming.

Our data-driven age is further pushing this blizzard of disjointed exercise and nutrition messages.

Platforms such as TikTok are awash with fitness influencers, some of whom offer advice of questionable value.

Amid crazes such as 2019’s celery juice fad – a relatively harmless but nutritionally pointless activity – more serious incidents have occurred.

In April 2021, a young woman in the US who followed an online trend – so-called dry scooping, that is, eating stimulant-rich pre-workout powder – later uploaded a video from a hospital after apparently suffering a heart attack.

A fatal flaw in much of the questionable fitness advice available online is that it lacks personalization. Everyone’s body is unique; variables in age, sex, and medical history – to name but a few – mean the same workout program or diet will have different results for different people, leading to disappointment and inconsistency at best.

If the WHO and national governments want to see fitter populations, the advice should be clear. Doctors generally agree that consistent physical movement – even banal activities such as walking, gardening, or housework – if performed for 30 minutes or so most days of the week, could help stave off the kind of chronic illnesses that burden public health systems the world over.

The link between sensible, moderate exercise and good mental health is also well established, making it even more important to establish and drive home a clear message that fitness is accessible and achievable.

Perhaps Juvenal said it best when he wrote in his Satire X: “What I commend to you, you can give to yourself.” Instead of abdicating responsibility for our well-being to others, we can and should take the simple steps we need to be that little bit fitter and healthier. That means avoiding the gimmicks and “hacks” that promise instant results, and understanding that we don’t all need to be athletes, we just need to future-proof our bodies for the years ahead.