The realm of sports physiology continually evolves as researchers delve into the intricate interplay between exercise, stress and hormonal responses. Among the various hormones implicated in the adaptive processes of athletes, cortisol stands out as a key player in the stress response. Cardiopulmonary Exercise Testing (CPET) has emerged as a valuable tool for comprehensively assessing an athlete's physiological capacity. Within this context, monitoring cortisol dynamics during CPET provides a unique window into the complex neuroendocrine adaptations occurring during physical exertion. This exploration aims to unravel the insights gained from scrutinizing blood and salivary cortisol variations through CPET, shedding light on the dynamic interplay between exercise stress and hormonal regulation in athletes