Our brain is our most powerful tool, shaping how we think, feel, and engage with the world. As we age, it evolves—enhancing our wisdom and judgement—but it also begins to slow in a process known as cognitive decline. This natural shift affects memory, focus, and problem-solving skills, often starting subtly in our 40s and becoming more noticeable by our mid-50s.
While occasional forgetfulness—like walking into a room and forgetting why—is normal in midlife, a new study has identified three key ages when cognitive decline speeds up: 57, 70, and 78. These shifts often align with major life transitions, such as menopause, retirement, and advanced ageing, highlighting the importance of proactive brain care.
While ageing is inevitable, understanding these changes and the different stages of life empowers us to take proactive steps to slow—or even prevent—normal cognitive decline. By making intentional choices, we can preserve memory, enhance focus, and keep our minds sharp and resilient for years to come.
The Science of Brain Ageing
A groundbreaking new study by Wei-Shi Liu et al, published in Nature Aging, analysed 4,500 healthy individuals and identified 13 key proteins linked to cognitive decline. These proteins influence:
- Inflammation & Immune Response – As we age, changes in the immune system can lead to increased inflammation, which is linked to normal cognitive decline. However, chronic inflammation is a key factor in the development of more serious neurodegenerative diseases.
- Neurodegeneration – Proteins associated with synaptic loss and neuronal death may explain worsening memory.
- Metabolic & Vascular Health – Brain ageing is closely linked to glucose metabolism and blood vessel function, both essential for cognitive health. Strong blood flow is crucial for delivering nutrients to brain cells and removing harmful toxins.
The study discovered that these 13 key proteins fluctuated in predictable patterns at ages 57, 70, and 78, aligning with major life transitions or stages. The study also found that these spikes were significantly more pronounced in those with poor lifestyle choices.
The findings reinforce the idea that lifestyle choices significantly impact brain ageing, providing hope that targeted interventions—like diet, exercise, and mental engagement—can help slow decline.
Dr. Sabine Donnai, a longevity expert, sums this dilemma up well - "lifestyle choices account for 90% of both the risk and the fix for cognitive decline".
With this in mind, we then turn to her insights, along with those of Professor Barbara Sahakian and Dr. Christelle Langley, authors of Brain Boost: Healthy Habits for a Happier Life, to explore practical ways to protect and enhance brain health at each of these stages.
Age-Related Cognitive Decline & What to Do About It
Let’s take a closer look at the critical ages and life stages when cognitive decline tends to accelerate—to understand what is happening and what can be done to slow or prevent it.
At 57: The Middle-Age Shift
Middle age and menopause are transitions associated with many physical and hormonal changes. As hormone levels fluctuate and metabolism slows, white matter—the brain's communication network—shrinks. The dreaded "middle-age spread" can further reduce blood supply to the brain, hindering nutrient transport.
- What helps? Exercise is incredibly neuroprotective, increasing hippocampus size and improving memory. Longevity experts recommend monitoring signs of a sluggish metabolism, such as blood sugar and cholesterol levels, as they affect your ability to manage weight and convert energy efficiently. You can also check hormone levels—including oestrogen, insulin, cortisol, and testosterone—which all play a vital role in brain health.
At 70: Retirement & Loss of Routine
Stepping away from work can lead to reduced mental stimulation and social interaction, key drivers of cognitive decline. These changes weaken the brain’s connections, making it harder to think and learn. As the brain continues to shrink and lose function, it becomes harder to remember things and process information. Studies show that loneliness and isolation, increases the risk of dementia by as much as 30% and 60% respectively. Five of the 13 identified proteins increased in response to loneliness.
- What helps? The saying "use it or lose it" holds true. Staying socially and mentally engaged can significantly help mitigate cognitive decline and build cognitive reserves. Focus on activities that challenge your brain – embrace new things like learning a language, dance, or take up a new hobby. Fostering connections is crucial, so find ways to meet new people.
At 78: Advanced Ageing & Inflammation
At this stage, brain volume shrinks further, blood flow decreases, and cognitive reserves are running low. Accumulation of inflammatory proteins accelerates memory issues and multitasking difficulties.
- What helps? Even now, it’s never too late to make changes. Eating an anti-inflammatory diet, staying physically active, and engaging in intellectually stimulating activities can still improve brain function.
How to Keep Your Brain Sharp: Science-Backed Strategies
Simple consistent habits can make a significant difference to your cognitive health and at any age. Here’s a summary of what the experts recommend.
- Move More – Exercise promotes blood flow, supporting neuron growth. Even walking helps.
- Eat Smart – Omega-3s, antioxidants, whole grains, and fermented foods support brain function.
- Prioritize Sleep – Quality sleep clears toxins and strengthens memory.
- Keep Learning – New skills and intellectual challenges build cognitive resilience.
- Stay Social – Meaningful connections reduce stress and improve mental clarity.
- Manage Stress – Mindfulness and meditation lower harmful cortisol levels.
- Limit Alcohol & Avoid Smoking – Both accelerate brain ageing.
Conclusion: Small Changes, Big Impact
While ageing is inevitable, cognitive decline isn’t set in stone. It’s never too late to make changes to improve cognitive function.
Our daily choices have a profound impact on brain health. By making small, consistent changes—moving more, eating well, prioritizing sleep, learning new things, and staying socially active—we can keep our brains sharp at any age and enjoy a healthier, more fulfilling life.
The key? Start today—your future self will thank you.