Want to make the most of your brain? Fall is your season

If you’re searching for some extra motivation, you’re in luck: it’s officially fall.

The shoulder season, arguably best known for its vibrant colours, isn’t often a season we think about when it comes to our brain function. Summer is praised for all that happiness-inducing sunshine, while winter gets short shrift: it’s bad for your mood, energy, and all around function. Plus, if you’re plagued by seasonal affective disorder, you’re also at risk of gaining weight.

But, as researchers based at Sunnybrook Health Sciences Centre and the University of Toronto recently discovered, fall harbours its own cerebral benefits.

Season to season your brain changes on a molecular level, one of the study’s authors Andrew Lim says.  So, he says, the researchers wanted to go one step further and find out if that change was reflected for older people in something clinically important, like your cognition.

Researchers followed 3,353 older adults in Chicago, Paris and Toronto, testing how well they were able to think and concentrate in summer, fall, winter and spring. They also tested their spinal fluid for Alzheimer-related proteins and measured the expression of their genes, specifically ones that are known to be related to thinking.

The study found “a robust association between season and cognition.”

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The brain function of those studied was 4.8 years younger in the summer and fall than it was in the winter and spring. In short, winter and spring aged their brains, but their cognitive youth bounced back in the summer and fall.

The study further found that the sweet spot is happening right now: late summer and early fall. In fact, people at risk of being classified as having mild cognitive impairment or dementia were more likely to meet the criteria for a diagnosis in the winter and spring and less likely to meet it in the summer and fall.

Unfortunately, an explanation why is at least one or more studies away from being known.

“The answer is we don’t yet know why,” Lim says, “but we’re very interested to find out.”

Tweet This Click to share quote on Twitter: "The answer is we don't yet know why," Lim says, "but we're very interested to find out."

So far, hypotheses include factors like temperature, day length, diet, hormones, and possible behavioural connections. But even without knowing exactly why, Lim says the discovery that there are “huge seasonal variations” in spinal fluid protein levels linked with Alzheimer’s could make a difference for those who are impacted by the disease.

On one hand, he says, it helps provide some context for why someone might struggle cognitively in the spring only to regain some cognition in the fall that they or their loved ones might have thought was permanently lost.

He explains further: what you might see as Alzheimer’s could possibly be seasonal, rather than the disease.

Lim says the research also raises a question of how much support we provide to people who have Alzheimer’s and whether we should be increasing resources seasonally in anticipation of fluctuations in cognitive levels.

Although he’s enthused about the work, Lim cautions it isn’t without its limitations.

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Although the study spans five groups in three countries, he notes that geographically they’re pretty similar. They’re all in industrialized areas with temperate climates in the northern hemisphere. Also, most of the people surveyed were of “European extraction,” although one group was made up of primarily African Americans.

Whether the results hold true closer to the equator or among people of different ethnicities remains to be seen.

“We need to do a lot more work to leverage or understanding of this to improve cognition, Lim says.