Is there an exercise goldilocks zone to help brain ageing?
There’s been quite a bit of research now which confirms that exercise is not only good for the body but also good for the brain. Trouble is up until now we haven’t had much clue as to how much and at what intensity. Well now we know.
The latest research was conducted by a collaborative team from several Chinese institutions, including the School of Public Health at Hangzhou Normal University, the Department of Psychiatry at Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, the School of Integrative Medicine at Tianjin University of Traditional Chinese Medicine, the School of Public Health at Tianjin Medical University, and the National Institute of Health Data Science at Peking University.
The study hypothesised that different levels of physical activity (PA), as objectively measured by accelerometers, are associated with brain ageing, specifically with the brain age gap. They thought that both insufficient and excessive PA might be linked to accelerated brain ageing, suggesting a potential U-shaped relationship, and that engaging in moderate amounts of PA could be beneficial for brain health in middle-aged adults.
Findings
The brain age prediction model based on neuroimaging data and using an ensemble machine learning approach achieved high accuracy.
There was a U-shaped association between physical activity levels and brain age gap: both low (insufficient) and high (excessive) PA levels were linked with greater brain ageing, indicating that moderate PA might be optimal.
This association was significant across different intensities of physical activity—light, moderate, and vigorous.
The study captured weekly durations for each intensity type. Given that the relationship is U-shaped, it suggests that PA exceeding moderate-to-vigorous thresholds was associated with adverse effects on brain ageing.
Implications for mid life athletes
None of us are couch potatoes doing insufficient exercise so we don’t need to worry about that side of the U. However lots of mid life athletes trend towards a lot of high intensity exercise. I’ve heard numerous times - ‘no pain, no gain’. There’s a tendency to believe that unless they have really pushed themselves they haven’t done any exercise. Consequently quite a few id life athletes are doing several high intensity sessions per week. Some just do only high intensity sessions!
What do I mean by high intensity. Typically stuff at threshold heart rate - approx 85% of your max heart rate. I’m not against high intensity exercise but I would advise that 1-2 quality sessions a week are all that’s needed, even if we’re training for a competitive event. For those just focused on the long game - staying healthy well into old age, then 1 session a week definitely suffices.
As the study demonstrated excessive levels of PA are associated with accelerated brain ageing. Since light and moderate intensities were found to have beneficial associations, consistent activity at these levels, especially when distributed over several days, would probably contribute to healthier brain ageing and potentially reduce the risk of cognitive decline.
Conclusion:
Engaging in frequent (e.g., 5 days/week) light to moderate physical activity is probably beneficial for brain ageing.
The key is maintaining activity within the moderate-intensity range, avoiding excessive or very high-intensity PA that could be associated with accelerated brain ageing.
Consistency and balance appear crucial for maximising the neuroprotective benefits associated with physical activity.