Maintaining a healthy brain across your lifespan

The American Heart Association and the American Stroke Association describe brain health as the ability to function well in various aspects like thinking, moving, and feeling.

This applies to people of all ages, but when we talk about brain health in the context of aging, there are many terms and concepts like the "brain aging gap," "brain reserve," and "successful aging" that are used to describe different aspects of brain health. These terms cover various processes related to brain health as people get older.

From a simple perspective, the term "brain age gap" refers to how the brain can look or function older than expected for a person's actual age. This idea suggests that as we grow older, our brains may experience structural changes, but they can also maintain their function and even grow in certain ways.

When we talk about successful aging, we mean a path where individuals remain healthy in both body and mind while staying socially active. This involves maintaining the brain's structure and function as we age. So, it's about having a healthy brain without obvious disease signs.

Resilience, on the other hand, is the ability to deal with brain-related issues as we age. Even if someone doesn't feel or show signs of cognitive problems, their brain might still have signs of aging or degeneration. For example, someone may have brain changes associated with diseases like Alzheimer's but can still function normally.

Brain reserve is a concept that relates to how the brain adapts to the harmful effects of different health problems. Cognitive reserve is more about the brain's ability to stay mentally sharp even when facing aging or health challenges. In the study of brain health, it's crucial to understand both how the brain resists problems and how it copes with them.

Across lifetime, the brain undergoes substantial changes at various levels of observation spanning between molecular, cellular, network and systems levels.

The review found five main concerns that impact negatively on brain health: unhealthy eating habits, lack of physical activity, sleep issues, heart-related problems, and chronic inflammation. Left unchecked, these concerns can gradually add up and harm brain health.

However, if we intervene early and effectively, we can promote healthy brain aging. In the review, we helped identify a framework to test personalised strategies promoting brain health and preventing cognitive decline in old age.

Our approach begins by identifying factors that can be changed throughout a person's life - we call them LiMEE factors:

• Healthy nutrition
• Cardio-vascular health
• Anti-inflammatory state
• Physical activity
• Sleep hygiene

These factors are at the core of our concept because they can be treated or adjusted. We then lay out some assumptions about how these LiMEE factors affect brain health.

After that, we delve into the biological processes that explain how these factors relate to brain health as we get older.

By understanding and addressing these factors, we can develop personalized approaches to maintaining brain health as we live longer.