Mental activity not a factor in preventing effects of aging?

As a professional chair-dweller whose work is mostly done in my head, I have always comforted myself with the thought that although I might never run a marathon, at least my brain will be buff and toned by the time age catches up to all those athletes.

So imagine my disappointment, uh, surprise, when a study published in Neurology, the medical journal of the American Academy of Neurology, claimed that physical exercise is actually more beneficial than mentally stimulating activities in preventing cognitive decline. Study author Alan Gow, PhD, with the University of Edinburgh in Scotland, followed 638 seniors by recording their reported physical and mental activities over a 3-year period.

MRIs at the start and end of the study showed that physical activity resulted in less brain shrinkage, while mental activity appeared to have no effect. However, since these activities were self-reported rather than imposed, could it be that the study participants did not engage in enough (rigorous) mental activity to make a difference?

Then a new study came out last month: the Mental Activity and eXercise (MAX) trial, a randomized, controlled trial with a factorial design. The subjects were assigned to one of four groups: intensive mental activity/intensive exercise, intensive mental activity/control-level exercise, control-level mental activity/intensive exercise, or control-level mental activity/control-level exercise.

The surprising conclusion of this study was that all four of the groups showed improved brain function, with no difference between the intervention and control groups in

all four groups, leading the authors conclude that perhaps the amount of activity is more important than the level of activity. On the other hand, it has been suggested that maybe there wasn’t enough contrast between the interventional and control levels of activity. It could also be that 12 weeks is not long enough for reliable results.

So although these two studies come to different conclusions regarding mental activity, they do agree on one thing: exercise is good for the brain. So turn off that computer every now and then. Three hours on Facebook never counted as mental activity anyway.