Does your brain become less flexible as you age?

Cognitive flexibility declines with age. This has been shown in an analysis of 85 brain-imaging studies: older brains are less active in the rear regions, and activity shifts toward the front. At the same time, the pattern of activity across both sides of the brain tilts toward predominantly one side. These are signs of redistribution, not of complete failure.

The picture is more nuanced than simple decline. Middle-aged adults activate extra brain regions to weigh conflicting information; older adults switch more toward areas involved in planning. The brain adapts its strategy. What is more, the nervous system has a remarkable capacity to absorb damage: loss of nerve cells and the build-up of harmful proteins can be present for a long time before you notice any effects. That resilience has limits, however.

Aerobic exercise has the strongest support of any intervention. An analysis of 42 studies involving nearly 3,000 participants shows a small to moderate improvement in cognitive flexibility. The largest effect was found with mind-body exercise such as tai chi, over 13 to 24 weeks, 46 to 60 minutes per session, five to seven days per week. Planning ability did not improve in those studies, it should be noted. Even low exercise intensity was enough to benefit the brain; in healthy older adults, higher intensity was not needed for an additional effect.

Targeted cognitive training consistently improves performance on the practised tasks, and there are signs of modest growth in brain volume. Whether those gains also carry over to other tasks in daily life varies. Dancing looks promising and shows improvements in memory, attention and balance, but so far this has been examined in only eight studies, so caution is warranted.