Walking far enough and fast enough is key to keeping memory and life.

The Lobster Quadrille.

"Will you walk a little faster?" Said a whiting to a snail, "There's a porpoise close behind us, And he's treading on my tail."

Lewis Carroll, 1832-1898

Going for a walk, or being engaged in physical activity of some sort on a regular basis is essential to maintain brain fitness. Two new studies now add further weight to the evidence.

Walking far enough.

Walking for a distance of 5 miles a week for those with mild cognitive impairment (MCI) or Alzheimer’s disease, was shown in the first study to help the brain’s key memory and learning centres. A 5 mile weekly walk was associated with a slower decline in memory loss ( due to maintaining brain volume ie the number of brain cells) over a five-year period and gave protection to the brain for over 10 years. As for normal healthy adults in their late 70’s, walking at least 6 miles a week was shown to be needed to maintain brain volume and reduce cognitive decline. This ongoing 20 year study by the Department of Radiology at the University of Pittsburgh looked at the relationship between exercise and brain structure using a combination of 3-D MRI brain scans and mini-mental state exams.

In this study those not engaged in sufficient physical activity saw a drop of 5 of points on the mini-mental scores, compared to a drop of only one point in those who met the physical activity requirement.

Walking alone cannot cure Alzheimer’s, but engaging in enough physical activity can improve the brain’s ability to resist neuro-degenerative change and memory loss.

Walking fast enough.

In the second study published in JAMA, a person’s walking speed was shown to be a reliable marker for overall health and longevity. This may prove a useful predictor of survival length across age, race and height, and especially for those who remain independent and active over the age of 75.

For those of us with ageing parents or relatives, it can be a real concern when we see that the person concerned has “slowed down”.

This new study (also from the university of Pittsburgh) used data from nearly 35,000 people from 9 participating studies. Gait speed was measured in meters per second and all the participants assessed had to walk at their “normal” pace and from a standing start. The probability of survival was found to be most accurate for those over the age of 75 years. Predicted years of remaining life for each age and sex increased as gait speed increased. The average life expectancy walking speed was found to be 0.8 meters per second. For those walking at one meter or more per second, survival was longer than expected based on age and sex alone.

But, it’s no good cheating and speeding up, to make your average walk speed look faster. Nor is walking faster a guarantee of longevity.

However it may be that in the future, a person's walking speed could be used as part of an individual assessment to gauge the likelihood of not only expected length of survival but also the expected level of continuing independence and level of functioning.

Plus of course, walking confers those other great benefits of stabilising mood, and helping to maintain weight as well as slowing down memory decline.

These studies and others confirm that being physically active at all ages is essential for our health and well-being. It is also important to be active enough to keep our brains working as best we can, to improve our chance of living not just longer but also with our mental faculties intact.

Refs: Radiological Society of North America (2011, January 2). Walking slows progression of Alzheimer's, study suggests. ScienceDaily. Retrieved January 9, 2011, from http://www.sciencedaily.com¬ /releases/2010/11/101129101914.htm

1. M. Cesari. Role of Gait Speed in the Assessment of Older Patients. JAMA: The Journal of the American Medical Association, 2011; 305 (1): 93 DOI: 10.1001/jama.2010.1970 2. S. Studenski, S. Perera, K. Patel, C. Rosano, K. Faulkner, M. Inzitari, J. Brach, J. Chandler, P. Cawthon, E. B. Connor, M. Nevitt, M. Visser, S. Kritchevsky, S. Badinelli, T. Harris, A. B. Newman, J. Cauley, L. Ferrucci, J. Guralnik. Gait Speed and Survival in Older Adults. JAMA: The Journal of the American Medical Association, 2011; 305 (1): 50 DOI: 10.1001/jama.2010.1923