I have been reading articles claiming that serotonin, endorphins and BDNF are produced during exercise, but they never mention the intensity or duration of exercise for this to happen.
To not make this question too broad, I want to narrow it down to, lets say, a 4-5k run over 20 minutes.
How will this affect the brain? Which chemicals do the body produce that could have an effect on the brain? And, how much?
I am asking because I am always curious about the mechanisms underlying the effects of exercise on the brain and because it's always difficult to find information regarding results of exercise; Googling mostly results in content marketing articles (like this one for Buffer). Also, I have also asked a separate question regarding the effects of low-intensity aerobic exercise.