Can exercise cause brain fog?

Yes, exercise can sometimes lead to what is commonly referred to as "brain fog" or mental fatigue, particularly after long or very intense exercise sessions. Andrew Huberman has mentioned that after such workouts, people might experience diminished cognitive capacities due to lower brain oxygenation or due to the effects of heating and cooling of the brain, which can negatively impact cognition. This is particularly noticeable when trying to perform mental tasks immediately following rigorous exercise, where there might be a noticeable dip in the ability to think clearly or perform cognitive tasks effectively 1 2.