Aerobic exercise can improve your memory — if you start before this age
For people under 55, two-and-a-half hours a week might make a difference
Episodic memory, which involves the recollection of past personal experiences, is often the first mental faculty lost with age. And researchers haven’t had much luck in figuring out how to stall this inevitability. But a new analysis suggests that aerobic exercise might help, but only if started early enough in life.
What’s new — Aerobic exercise, which has several brain benefits and may slow aging, seems to slow the deterioration of a network crucial to personal memories. Still, past research found it doesn’t have much correlation to a better ability to recall past experiences.
A new meta-analysis, published last month in Communications Medicine, found that this might be because research is too heavily focused on improving the episodic memory of people already old and affected by cognitive decline. Instead, the researchers looked at people middle-aged and younger who are generally cognitively healthy. They conclude: “Aerobic exercise positively influences episodic memory among adults [younger than] 55 years without dementia.”
A routine of 50 minutes, three days a week for 26 weeks could make a difference.
Science in Action — The hippocampus plays a key role in recollection of one’s own life, organizing memories in contexts, and acting as the brain’s memory librarian. For instance, it cues up memories of the beach when you smell sunscreen or of Christmas when you see snow.
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The hippocampus is also more susceptible to age-related deterioration than other brain parts.
Aerobic exercise, the kind that raises your heart rate and increases oxygen intake, is correlated with an increased size of hippocampal gray matter volume and regular function of the hippocampus. Studies of lab rodents show that regular exercise on the hamster wheel leads to better performances in memory tasks.
Still, several meta-analyses — studies that synthesize the results of many clinical trials to come to a larger conclusion from current research — “found no benefits of [aerobic exercise] on [episodic memory] among older adults with or without cognitive decline,” according to the new paper.
The researchers, working from the University of Pittsburgh and Carnegie Mellon University, looked at the results for a certain age segment. For inclusion in their meta-analysis, studies had to have a participant pool that had a mean age younger than 55 and no dementia diagnosis. They found 36 studies with data from a total of 2,750 participants.
The meta-analysis hones in on people who still have time to influence the trajectory of their late-life cognitive health.
After adding some statistical controls to give more qualitative studies more weight and other factors, the meta-analysis showed that aerobic exercise improved episodic memory for adults, aged 55 and under with no dementia diagnosis. It seemed to have the best effect on people with normal cognition, not even mild impairment. Further, women seemed to benefit more than men.
However, the researchers were quick to note that the current data makes it hard to prescribe a specific exercise to everyone. The wide variety of regimens in the studies “limits our ability to definitively state an optimal exercise dose at which [episodic memory] benefits are detected or strengthened,” the authors write.
Still, they think the minimum time investment needed to make any difference was 3,900 minutes of activity. This could be accumulated in three 50-minute sessions, three days a week for 26 weeks — which is exactly the American Heart Association’s guideline of 150 minutes of moderate aerobic exercise per week.
What It’s a Hack — By excluding populations who are of advanced age or already experiencing decline, the meta-analysis hones in on people who still have time to influence the trajectory of their late-life cognitive health.
The authors list several possible mechanisms by which a morning run or Peloton ride could help one hold onto their memories for longer:
- Physical activity “improves mood, which can positively impact memory.”
- “[E]xercise appears to positively impact hippocampal structure and function, especially in older adult populations.” Aerobic exercise increases the release or effect of several brain chemicals that are good for the hippocampus.
- Aerobic exercise “might regulate an anti-inflammatory response in humans.”
- Exercise can induce physiological changes, “including decreased body weight and cardiovascular responses and reactivity, which could influence brain health outcomes.”
How This Affects Longevity — As the researchers note, exercising early on in life, and staying consistent with it, could help stall the aging process and prevent various neurodegenerative diseases, such as Parkinson’s disease and Huntington’s disease.
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