How Exercise Affects Our Memory | Hacker News Reader

How Exercise Affects Our Memory

nytimes.com

86 pointserickhill21 comments

Sample size: 26. Confounding variable: all older people. Also the exercisers did not perform significantly better in the memory test! They only had higher activation in the regions of the brain associated with memory! Really a garbage conclusion from the actual article

... Isn't increased brain activity a sign of worse performance? Because when your brain is actually operating efficiently, it doesn't need to light up very many neurons to do what it needs to do.

This is literally what is said in TFA:

> Less activity suggests that the brain had become more efficient at semantic-memory processing as a result of the exercise, requiring fewer resources to access the memories.

It's clear in the paper that their result is the other way around, exercise was correlated with higher activation intensity.

https://www.cambridge.org/core/services/aop-cambridge-core/c...

The activation intensity isn't necessarily a measure of efficiency anyway. There wasn't a difference in blood flow, so energy use would have been similar.

On the other hand, forgetfulness and memory loss is associated with simply losing access to the neurons. If your memory bus was faulty, DRAM would be pretty quiet.

Not hard to imagine the degenerate case though.

Hey, remember X? Nope.

Checking more things before returning the negative result might be better.

The memory test was designed not to measure performance (the names presented were preselected so that performance with each of them exceeded 90%).

For a real effect, a sample size of 26 is going to show it just fine.

Depends on the effect size.

Surely.

But I know that this is true for me. I can tell at the end of the day whether I worked out or not just by how I feel.

Without workouts I feel foggy, slow, unmotivated.

Doing cardio I feel 25.

Same for others so I hope they continue this research.

Hardly even anecdotal, just my personal experience: I always disliked sports, and I would't dream of entering a 'fitness center' or whatever they're called. I do a minute or two with hand-weights every morning, I walk my dog, and I bike [pedals, not motor] a bit - the oldfashioned way, nothing fancy or spandexed about it. But am often puzzled by everyone's physical passivity: I don't really get the point of escalators, for example. I tend to trot up the stairs if they are available, in the process generally overtaking the stand-still folks on the conveyor. It seems to work: I'm sixty and in very decent shape and excellent health.

As for kickstarting my brain when it goes mushy, honestly I find driving at least as efficient as walking or biking. Change of scenery, not having to think, seems to do the trick for me.

Anecdotally, long periods of exercise (cycling 50+ miles in a single session, once a week) seem to nuke my short-term memory for a few hours, but over time this habit seems to have improved my short-term memory for things such as phone number extensions.

I have the same experience after rugby matches and open water swimming — my short-term memory is shot for the next few hours, but then it recovers. I have no evidence for the long-term effects.

It might sound dumb, but whenever I'm stuck and I need to solve a hard coding problem, a long walk does the trick.

Do trips also work (car, train, or else) ?

Also being in a different location unleashes a lot of inspiration very often.

I think there's decent evidence that low intensity exercise can increase BDNF which helps increase neural connections. Not really the same as this study, but a different effect of exercise on the brain

As I recall there is such evidence, but there's also evidence that commonly encountered concentrations of particulate air pollution drastically reduce that increase in BDNF. So it's not entirely clear what mechanisms all have to be working well to see that particular benefit.

Methinks sleep increases memory performance more.

If exercise helps you sleep better, A -> B -> C

Sleep helps you exercise better moreso than the inverse.

IIRC, I exercised yesterday.

I wonder if those who primarily benefit from exercise based are primarily older people. If it's not, then either I need to see a neurologist, start exercising harder/more frequently, or both.

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