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Sebastian Rushworth MD: Does exercise improve cognitive function?
Real science is never settled, and anyone who has certainty on such things is not qualified to discuss it.
Good studies on health vs lifestyle are an oxymoron perhaps.
Sebastian Rushworth MD: Does exercise improve cognitive function
by Sebastian Rushworth M.D.., 21 August 2021. Emphasis added.
I guess I’m biased against the idea that exercise is very important for health. I hated sports as a kid, and efforts at getting “fit” as an adult have generally ended in failure within months... I’ve written previously about how exercise is not a particularly effective way to lose weight, and about how vigorous exercise will not make you live longer than if you stick with moderate exercise, such as walking – in fact, 10,000 steps of moderate intensity walking per day is all you need, if the goal is to maximize longevity. Which suits me just fine, because that’s about as much exercise as I can bring myself to do.
But there could be other benefits associated with exercise. Elderly people who suffer from sarcopenia (muscle wasting) clearly benefit from strength training as a means to maintain functional independence for as long as possible, as do people with osteoporosis (a weak and fracture-prone skeleton). It has also frequently been claimed that exercise improves cognitive function. That claim has however up to now been based more on wishful thinking than on any actual evidence.
A systematic review carried out by the Cochrane Collaboration in 2015 failed to show any benefits of aerobic exercise on cognitive function, but that review was limited by the fact that all the included trials were small and short term – in other words the data was statistically underpowered. Which is why it’s nice to see that a large randomized controlled trial has now been published in the American Journal of Clinical Nutrition, that sought to answer definitively the question of whether exercise improves cognitive function. This new trial included 1,401 participants in total and they were followed for an average of four years, so if there is a meaningful difference it should be detectable...
...The control group basically received zero attention, the single intervention groups received some attention, and the dual intervention groups received a lot of attention. Any difference in outcomes between the groups could thus simply be due to differences in how much attention they were getting from the people conducting the study – it is a well known fact that the more attention study participants are getting, the better they will tend to perform. This is poor trial design. A properly designed trial should give equal attention to all participants, including those in the control group, so that any difference seen in outcomes isn’t just due to differences in how much attention the participants are getting...
...this study cannot say what will happen to cognitive function if you take someone who literally just lies in bed all day, and then get them to do some exercise – it tells us what will happen if you take someone who already does some walking per day (as most people do), and then get them to do more exercise...
...this study cannot say anything about effects of diet on cognitive function...all this effort had exactly zero impact on cognitive function. None of the five intervention groups showed an improvement in cognitive function at four years when compared with the control group. There were marginal variations between the groups but they were neither statistically significant nor clinically significant...
...
What can we conclude?
Two things. First, you can’t trust what researchers claim their research shows. Second, exercise does not noticeably improve cognitive function.
WIND: IMO, the study is incredibly narrow in what it is looking for (cognitive function in a lab setting), and for too short of a time. The crucial years come in the 70's and 80's. And why should very moderate exercise on top of mild exercise change anything?
I now for myself that exercise always makes me feel good, and that the more fit I am, the better I feel, the more alert I feel, etc. And I feel strongly that exercise was critical to faster recovery from my 2018 concussion, namely, increased blood flow.
