It’s quite likely that you’ve never heard of the Greco-Roman physician and philosopher Galen of Pergamon. He was court physician to Marcus Aurelius’s son Commodus and he also found time to write… a lot.

His written work is said to account for around 10% of all extant Greek literature from before AD350. Not only that, but the theories he posited influenced Western society – and especially the field of medicine – for more than 1,000 years after his death.

Galen’s lessons took a three-pronged approach, concentrating on the soul, alongside improving your diet and taking regular exercise.

And while some of his advice was founded on long-disproved science, could some of his 1,800-year-old lessons still be helpful in the 21st century?

Keep reading to find out.

1. Take the time to reflect and ask what changes you might need to make

Galen wrote: “Whoever wants to become a fine and good person, let him bear in mind that one is necessarily unaware of many of one’s own errors.”

To find your faults or areas for improvement, the ancient philosopher suggests gaining a second opinion, specifically from “older men who have lived the best sort of lives”.

In the 21st century, internal reflection might be the best place to start.

Think about the things that make you happy. Journalling or list-writing might help you to think about the things you are grateful for. Don’t dwell on regrets or failures. Instead, use your lists to think about areas where you could be even happier or where small changes could make a huge difference.

Maybe you’re grateful for your friends and family but would like to make a bigger effort to see them more often, for example.

When you have taken an objective look at yourself, speak to family and friends across the generations and find out their views. The conversations you have might surprise you.

Galen is right: sometimes an objective outside opinion can be useful, so don’t be shy to use your support network.

2. Take regular exercise… with or without a small ball

While Galen was quick to advocate for regular exercise, he wasn’t keen on gyms. In fact, he thought gym goers were “idle, drowsy, and slow in judgment”. He did, though, recommend exercise “with a small ball”.

The details of this mysterious regime are long-forgotten, though the process was related to Galen’s belief in keeping a balance between the “four humours” and was said to involve “many neck grabs and wrestling holds”.

The need to balance our “four humours” to ensure good health has been disproved by modern science (the humours were said to be blood, yellow bile, black bile, and phlegm) but taking up a team sport does still make sense in 2024.

Outdoor sports can provide fresh air and exercise as well as some important life lessons. Wins teach humility while losses can help build resilience and improved perseverance.

The emotional rollercoaster of a single match or season can help with self-regulation, providing you with important coping mechanisms, while being part of a team is a great motivation for training hard and doing your best.

Joining a local sports club can keep you physically fit and socially active, important for your overall wellbeing.

3. Maintain a healthy diet

Galen’s dietary beliefs were, worryingly, also centred around his four humours. Each humour roughly equated to personality traits and foods could then be used to keep certain traits, like hot-headedness or cheerfulness, in balance.

This theory, of course, is largely nonsense. But the need for a balanced diet remains valid.

Consider the Mediterranean diet, which is high in vegetables, fruits, and legumes. A predominantly plant-based diet can help you to move away from saturated fats that are prominent in cheese, biscuits, and fatty meats.

The Mediterranean diet also favours unsaturated fats like those found in olive oil, nuts, and oily fish.

4. Be prepared to admit you might be wrong

Galen was very firm in his beliefs, including the existence of the four humours. And, as we’ve already said, some of his beliefs were influential for a long time. Humourism, for example, was a crucial arm of Western medicine until the 19th century.

But Galen was wrong on some points. And while we now have a better understanding of science than Galen did, we mustn’t rest on our laurels. Instead, we must always be keen to learn, try new things, and acknowledge that our old beliefs might be wrong.

Be reflective, humble, and practice humility.