Regular Aerobic Exercise in Midlife Protects the Aging Brain

In recent years, countless studies have identified extensive neuroprotective benefits associated with aerobic exercise, cardiorespiratory fitness, and the aging brain. Previous research has found that older adults who exercise regularly have increased brain volume in the hippocampus and cerebellum, perform better on memory tasks, and have a lower risk of dementia when compared to older, sedentary adults with low cardiorespiratory fitness.

Today, at the American Heart Association's International Stroke Conference 2017, researchers from the University of North Carolina (UNC) presented more cutting-edge empirical evidence illustrating unique ways that regular aerobic exercise during middle age can protect the aging brain.

Regular aerobic exercise during midlife appears to lessen the severity of a stroke in older age by improving collateral circulation, according to the latest findings from a study on mice by James Faber and Wojciech Rzechorzek of UNC. (Collateral circulation is a process by which normally closed arteries open up and begin to reroute blood flow to parts of the heart when a coronary artery is blocked, or to a part of the brain when a cerebral artery is blocked.)

2017 Stroke Statistics At-a-Glance (From the American Stroke Association)

• Someone in the US has a stroke about once every 40 seconds.
• Stroke is a leading cause of serious long-term disability in the US.
• Stroke accounts for 1 of every 20 deaths in the US.
• Stroke kills someone in the US about every 4 minutes.
• When considered separately from other cardiovascular diseases, stroke ranks No. 5 among all cause of death in the US, killing nearly 133,000 people a year.

As people (and mice) get older, the network of blood vessels and collateral circulation tend to shrink both in number and diameter. However, Faber and Rzechorzek found that a middle-aged mouse who began exercising regularly had the same abundance of collateral vessels when it reached the equivalent of a 70-year-old human as much younger counterparts. Conversely, middle-aged mice who didn't exercise regularly lost both collateral vessels and circulation progressively as they aged.

Additionally, if an older mouse had been exercising regularly and suffered a stroke—there was significantly less brain damage because robust collateral vessels kept blood flowing to the brain despite the blockage. Aerobically active mice also had higher levels of molecules that help blood vessels work properly and stay healthy, which can reduce the risk of stroke.

Although this was an animal study, Faber and Rzechorzek believe their findings suggest that regular aerobic exercise across a lifespan may protect collateral circulation and lessen the severity of strokes later in life for humans, too.