„It is exercise alone that supports the spirits, and keeps the mind in vigor.“ (Marcus Tullius Cicero)
Extended average lifespan has resulted in increased prevalence of age-related neurodegenerative disorders including dementia, Alzheimer’s and Parkinson’s disease, with approximately 3% (57.5 million) of the world’s population currently affected. Modifiable risk factors include physical inactivity, mid-life high-blood pressure, obesity, diabetes and smoking. Of these, physical inactivity is the greatest risk to later-life mental decline.
Physical activity exerts indirect and direct effects on brain health. Indirectly, being active reduces other risk factors for mental decline such as obesity, high-blood pressure, cardiovascular disease and diabetes. Directly, increased fitness positively influences brain structure and function, with activity being linearly related to brain volume in general, and grey matter volume in particular. Being physically active appears particularly important in mid / later life to maintain structural integrity and brain size, and to prevent vascular issues that lead to future mental decline.
Increasing physical activity can have positive effects at any age. Just 20 minutes of walking increases brain activity and mental-test performance in children (Fig. 1), and as little as 4-6 months of outdoor walking produces growth of new brain matter and improvements in learning, working memory and information-processing speed in 65-80 year olds. Given the connection between physical activity and brain health, increasing physical activity might be the most effective way to prevent or delay the decline in mental function with age, if undertaken before the onset of the decline.
Figure 1: Composite EEG activity of 20 children after quiet sitting and a 20-minute treadmill walk.
Dr. Mick Wilkinson, PhD, MSc, BA (Hons)
Northumbria University, Newcastle, England
Senior Lecturer in Sport and Exercise Science & Department Ethics Lead