But for me, walking is a good opportunity to process the day and let my mind wander without the oppression of the endless to-do list that awaits me at home. Plus, it helps my back recover from a day spent bent in front of a computer screen. Health-wise, I have always assumed I'd have the last laugh, and now there's even more evidence on my side.

　　A study published in Neurology has found that the simple act of walking may improve memory in old age. As we age, our brains shrink and the shrinkage is associated with dementia and loss of cognitive functions such as memory. To test whether physical activity could mitigate some of these degenerative effects, researchers from the University of Pittsburgh tracked the physical activity of 299 healthy men and women with an average age of 78. The participants' activity ranged anywhere from walking 0 blocks to 300 blocks (up to 30 miles) per week.

　　Nine years later, the walkers underwent brain scans, which revealed that those who had walked more had greater brain volume than those who walked less. Four years after that, the volunteers were tested again — this time for dementia. Among the group, 116 people showed signs of memory loss or dementia. Those who had walked the most — at least 72 city blocks (or about 7 mi.) each week — were half as likely to have cognitive problems as those who walked the least.

　　The findings are in line with past studies linking physical activity with brain function, but dementia experts say there's not enough data yet to prescribe exercise to prevent memory loss. It's also too soon to say whether exercise may prevent dementia or simply delay it in people who would eventually develop it anyway. But when it comes to Alzheimer's, even a short delay could mean great gains in quality of life.