How little exercise will produce the reaction-time-lowering effect I’ve found (here and here)? I decided to measure the effect of a 10-minute walk from a BART stop to a cafe. (Nicely integrating work and work.) But I got off BART at the wrong stop and my 10-minute walk took 40 minutes.
Here is what happened:
Just as with a 30-minute treadmill walk, the effect was delayed.
This is more support for the idea that exercise temporarily improves brain function. The novelty in this particular experiment is that the exercise was “real” rather than on an indoor treadmill.
For comparison, here are earlier results from much more strenuous exercise (30 minutes walking uphill on a treadmill):
The effect of more strenuous exercise was larger and lasted longer. With the easier exercise (the stroll) there was a downward spike in reaction time; with the more difficult exercise (the climb) there was a more crater-like effect. The spike shape suggests the effect was sub-maximal; the crater shape suggests that the maximum effect was reached. Which makes sense because the climb was close to maximum effort, whereas the stroll was far below it.
A kind reader pointed to a NY Times article on the brain effects of exercise. “Exercise can, in fact, create a stronger, faster brain,” says the article. “Create” refers to neurogenesis. The effects I’ve observed are more temporary — more like adding better fuel to a car.
“The human brain is extremely difficult to study, especially when a person is still alive,” says the article. Not entirely true.
For what it’s worth, a general finding about performance and the presence of others, which is believed to be an effect of arousal. We perform well-learned easy tasks, like simple arithmetic or tying our shoes better, faster, when in the presence of other people. The presence of others is arousing physiologically and that makes it easier.
We perform more novel, difficult tasks worse in the presence of other people; it is believed because we are more aroused. It was suspected that this was because we feared being judged by others, but it holds even if the others present cannot see us.
Robert Zajonc is the one who theorized all of this, that is, made sense of the disparate findings about performing better or worse around other people.
I wonder if the arousal effects of exercise might differentiate in terms of easy versus difficult tasks.
Am I reading the results right?. The peak effect of exercise is after 1-2 hours?. I think this is important to schedule exercise the right time before you need to be sharper. Thanks.
It looks like anyone who isn’t hitting the gym right before taking the SAT or Bar exams is making a big mistake!
That’s right — the peak effect of exercise is afterwards.