I found this chart detailing stress response as it relates to heart rate in Miltary Servicemen.
|Heart Rate and Subject's Response to Stress|
|HR 60-80bpm||Normal Resting Heart Rate|
|HR 115-120||Fine Motor Skill deteriorates|
|HR 120-145||Optimal for Complex Motor Skills and Reaction Time|
|HR 145-150||Complex Motor Skill Deteriorates|
Loss of Peripheral Vision (Tunnel Vision)
Loss of Near Vision
Cognitive Processing Deteriorates
Loss of Depth Perception Auditory
Auditory Exclusion (Tunnel Hearing)
Loss of Gross Motor Skills
Irrational Fleeing, Fighting or Submissive Behaviour
There seems to be a correlative relationship as the heart rate moves further from a normal resting rate and the decline of certain physical and cognitive qualities.
Their findings imply that the more cardiovascularly trained an operator is, the better decisions they will make when under duress.
Ranger A's heart rate ramps up to 175 beats per min after a 200meter sprint from one building to another with 40lbs of combat gear.
Ranger B's heart rate hovers around 145 bpm after the same task.
Ranger B is much more likely to be able to take in complex information, plan and execute an appropriate course of action.
I don't think it's too big of a stretch to suggest that this parallels what happens on the gym floor.
We've seen some strange decisions, degeneration of motor skills, and tunnel hearing during conditioning pieces or max effort lifts.
Cardio isn't just for endurance athletes.
Conditioning the heart can help prevent detours into sloppy town, and help the athlete produce a higher relative output for longer.