Physical exercise CANNOT replicate stress-other than a pounding heart and faster breathing. None of the other associated affects-things slowing down, tunnel vision, auditory exclusion, etc. will occur due to exercise only.
To practice for stress you must induce stress-google it-time constraints, performing in front of others, the "hood" drill, adding noise, differing lighting conditions, etc. can give you what you are looking for.

Duane