Could exercise protect against Alzheimer’s disease?

Alzheimer’s disease understandably frightens most of us, especially since the condition is currently incurable and few treatments appear to curb its progression. However, a new study suggests that for certain high-risk individuals, a daily walk or jog could reduce the risk of developing Alzheimer’s or at the very least slow the course of the disease.

Researchers recruited 201 adults between the ages of 45 and 88, some with a family history of Alzheimer’s, but none with clinical symptoms of the disease. The volunteers underwent a brain scan to identify signs of amyloid plaques in their brain. These deposits are known to be a hallmark of Alzheimer’s, although the relationship between the plaques and the onset of symptoms is complex. The participants were also genetically tested for a specific gene called APOE. People with a particular variation of the gene are 15 times more likely to develop Alzheimer’s and tend to show symptoms at a younger age, in their late 60s on average compared with early 80s in people without this gene variant. Lastly, the volunteers filled out a questionnaire about their exercise habits over the past 10 years.

The results were quite interesting: When the researchers looked at the group as a whole, they found that regular exercise only had a minor impact on amyloid plaques. The results were very different, however, when they took a separate look at the participants with the specific APOE gene variant that predisposes people to Alzheimer’s. Not surprisingly, most of these carriers had much larger accumulations of amyloid plaques. The surprising part was that the gene variant carriers who walked or jogged for at least 30 minutes five times a week had a plaque accumulation similar to that of volunteers who did not carry this gene variant.

In other words, regular physical exercise partly neutralizes the effect of the gene variant and seems to protect us against developing Alzheimer’s. The results need to be confirmed by further research, but for the moment they are a strong incentive for people at risk of developing Alzheimer’s to exercise regularly.