Heart rate - Increases or decreases as arousal increases or decreases

Drive Theory essentially predicts that performance increases in a linear fashion as arousal increases. More precisely, drive theory predicts that performance is a function of the interaction between habit and drive (arousal).

Commonly used measures of AROUSAL
Brain activity - Changes are thought to reflect changes in arousal; alpha activity is thought to reflext low arousal (relaxation), whereas beta activity is thought to reflect higher levels of arousal

Heart rate - Increases or decreases as arousal increases or decreases

Cortisol - A stress hormone released during an encounter with a stressor or challenge (physical or psychological)

Introduction to Exercise Science - By Stanley P. Brown

Published 2000 - Medical - page 321
Lippincott Williams
& Wilkins