Physical Activity and Cognitive Function of Long-Distance Walkers: Studying Four Days Marches Participants.

Studies show physical activity to be beneficial for cognitive function. However, studies usually included individuals who were not particularly inclined to exercise. Following research among master athletes, we examined associations between physical activity and cognitive function in participants of the International Nijmegen Four Days Marches. These individuals are also inclined to exercise. On 4 consecutive days >40,000 participants walk a daily distance of 30-50 km (120-200 km or 75-125 miles in total). Four Days Marches participants and less active or inactive control participants from the Nijmegen Exercise Study were examined. Self-reported current and lifelong physical activities were quantified in Metabolic Equivalent of Task minutes/day, and training walking speed was estimated in km/h. Cognitive functioning in the domains of working memory, executive function, and visuospatial short-term memory was assessed using the validated Brain Aging Monitor. Data from 521 participants (mean age 54.7, standard deviation 12.9) showed neither positive associations between lifelong physical activity and working memory, executive function, and visuospatial short-term memory nor positive associations between current physical activity and cognitive functioning in these domains (p-values >0.05). However, a positive association between training walking speed and working memory was revealed (age adjusted β = 0.18, p-value <0.01). Walking speed as a surrogate marker of fitness, but not lifelong and current physical activity levels was associated with cognitive function. Therefore, walking speed deserves more attention in research aimed at unraveling associations between physical activity and cognitive function.