The International University of La Rioja (UNIR), in collaboration with University College London, has promoted research that confirms that the cortisol response upon waking "triples" in footballers during competition mornings.
According to specialists from this Spanish academic center, "elite footballers experience an 82.1 percent increase in their cortisol levels as soon as they open their eyes on competition mornings, compared to 24.7 percent on rest days." The work was carried out with 190 high-level athletes and a scientific team that also included researchers from the University of Malaga and the Warsaw Research Institute (Poland).
The authors conclude that "this hormonal production, which triples the usual biological response, functions as an automated 'ignition' system for the body to face the demands of the match on the day of the official competition." Thus, for professional players, "the real match begins long before stepping onto the field: specifically, at the exact second they wake up," they pointed out.
In the words of Manuel Jiménez, a UNIR researcher and lead author of the work, "the study reveals that the cortisol response upon waking could be an anticipatory activation, an urgent and acute mobilization, linked to the subjective estimation of the challenges we will face that day," further emphasizing that "in biological terms, the brain acts as a predictive system."
Thus, he explained that this organ "anticipates the importance of the challenge to come and sets in motion a cascade response that prepares the body to perform at its best even before the competition begins." The results have been disseminated in the specialized scientific journal 'Psychoneuroendocrinology'.
Key mechanism for activating the body before the game
Delving into the study's design, the university detailed that "saliva samples from 190 top-division athletes from various disciplines - including professional footballers from the best European leagues - were analyzed." This protocol has verified that the described phenomenon "is a key neuroendocrine mechanism for mobilizing energy, increasing alertness, and preparing the metabolic and nervous systems before the game."
"The main finding of the study, which analyzed cortisol concentrations just upon waking and 30 minutes later on official match days and rest days, confirms the so-called 'Anticipation Hypothesis'," the researchers indicated, alluding to the fact that this theory holds that the cortisol response upon waking "is not a simple reactive response to stress, but an adaptive and biological mechanism that prepares the body for demanding tasks."
Therefore, they consider that the cortisol response upon waking is "a key biological marker for the physical and mental preparation of athletes. Throughout evolution, it must have been a biological advantage to be alert and prepared to respond to threats immediately upon waking, coinciding with the increase in sunlight," Jiménez commented.
In the field of high performance, the researcher emphasizes that "in professional sports, ensuring that each individual's cortisol response upon waking is precisely adjusted to the real needs of the challenge ahead represents, without a doubt, a fundamental competitive advantage," while also warning that "overactivation or hypoactivation of the neuroendocrine systems could be maladaptive and hinder the athlete's ability to beat their rivals."
As a practical application, the authors propose monitoring this indicator "as a scientific tool to measure the real competitive readiness of footballers." "The results showed an individual variability of 47.3 percent with respect to the mean, which confirms that each player possesses a unique 'activation clock'," they pointed out.
In this regard, they warn that "if the player undergoes excessive stress or suffers disruptions in their rest, something common in the training camps of major tournaments, their endocrine system may have its response capacity altered, which affects their performance and is directly associated with a higher risk of suffering muscle injuries," they concluded, also highlighting that "this study shows that, at the world elite level, a footballer's body activates with the same intensity in the morning as that of an athlete who competes alone."