The Ancient Partnership Behind Our Health and Intelligence

Sleep, exercise, and a balanced diet are often recommended as essential habits for maintaining good health. However, have you ever stopped to think about why these three seemingly different habits have such a profound impact on our brains and bodies?

For generations, we've treated sleep, exercise, and nutrition as separate prescriptions, each serving a distinct purpose. However, neuroscience is beginning to suggest that they're all interconnected, working towards the same goal.

The key to understanding this connection lies in the biology of the brain. Research has shown that cognition is an energy-intensive process, with the brain using a significant portion of the body's energy at rest. This raises an important question: where does all that energy come from?

The answer lies in the partnership between our cells and mitochondria, the descendants of ancient bacteria that formed a long-term alliance with our ancestors over 2 billion years ago. Mitochondria are responsible for capturing the chemical energy stored in food and transforming it into ATP, the molecule that powers almost every biological process.

This partnership is still running inside us today, with mitochondria existing in almost every cell in the body. The exception is the mature red blood cell, which removes them to make space for haemoglobin and improve oxygen transport.

For decades, mitochondria were viewed as the cell's "powerhouses," but today, they're recognized as active participants in the delicate balancing act that allows the brain to adapt, learn, and flourish throughout life. Emerging evidence suggests that healthy mitochondrial function is linked to intelligence, including arithmetic and processing speed, working memory, healthier brain ageing, and greater resilience to stress.

This new understanding of the role of mitochondria in our health and intelligence has significant implications for our lifestyle choices. Exercise, for example, doesn't just boost muscle mass; it also encourages mitochondria to become more numerous and more efficient. Sleep performs a different kind of maintenance, consolidating memories and repairing or replacing worn-out cellular components, including mitochondria.

Then there's food. Mitochondria rely entirely on what we eat to perform their remarkable chemistry, and the quality of that fuel matters. Diets rich in minimally processed foods provide the ingredients for efficient energy transformation, while diets that continually overwhelm the system appear to make that process less efficient over time.

Seen through this lens, sleep, exercise, and diet stop looking like three separate pieces of lifestyle advice and become different ways of caring for the same biological inheritance.

## The Mitochondrial Connection

Mitochondria are no longer viewed as passive batteries but as active participants in the delicate balancing act that allows the brain to adapt, learn, and flourish throughout life. They're responsible for capturing the chemical energy stored in food and transforming it into ATP, the molecule that powers almost every biological process.

## The Ancient Partnership

The partnership between our cells and mitochondria is still running inside us today, with mitochondria existing in almost every cell in the body. This partnership is the key to understanding why sleep, exercise, and a balanced diet are essential for maintaining good health and intelligence.

## The Implications

This new understanding of the role of mitochondria in our health and intelligence has significant implications for our lifestyle choices. By caring for our mitochondria through sleep, exercise, and a healthy diet, we can improve our cognitive function, boost our resilience to stress, and promote healthier brain ageing.

The tiny descendants of that ancient bacterium have been quietly working inside us ever since, making possible not just movement or metabolism but thought itself. Perhaps that's why the oldest health advice has survived every new scientific fashion. Long before we knew about ATP, oxidative phosphorylation, or mitochondria, we recognised that people who slept well, moved regularly, and ate nourishing food tended to flourish. We're finally beginning to understand why.

**Recommended Reading**

- The Song of the Cell by Siddhartha Mukherjee (Vintage, £14.99) - Transformer: The Deep Chemistry of Life and Death by Nick Lane (Profile, £14.99) - How Life Works: A User’s Guide to the New Biology by Philip Ball (Picador, £14.99)