What? Is there any evidence to support this statement?
I know I (personally, anecdotally) am a way calmer, more rational and reasonable decision maker after bouts of intense exercise. - Heavy lifting sessions, hard sports training, etc.
The Inverted U Hypothesis (aka Yerkes-Dodson law - https://en.wikipedia.org/wiki/Yerkes%E2%80%93Dodson_law) and https://www.mindtools.com/pages/article/inverted-u.htm was the first to posit the relationship between Arousal and Performance. However there are lots of nuances to this. The important one is Cue Utilization Theory (https://www.elitetrack.com/blogs-details-7362/ and https://psychology.iresearchnet.com/sports-psychology/percep...) which is relevant for decision making.
Coming to Exercise Intensity and Decision Making you may find the following papers helpful for some empirical data.
* Influence of exercise intensity on the decision-making performance of experienced and inexperienced soccer players - https://pubmed.ncbi.nlm.nih.gov/19454768/ and Fontana's thesis at https://core.ac.uk/download/pdf/12206332.pdf
* Effect of Exercise Intensity Level on Choice Reaction Time - https://journals.sagepub.com/doi/full/10.2466/11.03.CP.4.3
PS: I have linked to two relevant books in another post of mine in this thread which you may find useful.
To take it further, recent studies suggest that exercise more strenuous than just walking makes you better at dealing with uncomfortable decisions and situations (as exercise forces you to power through discomfort).
https://www.thecut.com/2016/06/how-exercise-shapes-you-far-b...