Stress research for athletes using physiological indicators—Application to the study of endocrine system—

Abstract

Athletes tend to conceal their tiredness for various reasons, including environmental and cultural factors, high motivation to increase their competitiveness, and the desire to be selected for games. Stress evaluation using physiological indicators has been focused as a method of evaluating the stress levels of such athletes. In this paper, we reviewed research that has used cortisol, which is an indicator of the endocrine system. However, athletes regularly perform high-load training; and cortisol as a stress index is susceptible to the effects of exercise, metabolism, and immunosuppression. Therefore, it is necessary to consider its specificity. Moreover, when evaluating stress, it is necessary to consider physical and psychological stress separately. However, this line of research has begun only recently, and future developments are required. Recently, studies have begun to focus on the possibility of recovering from stress by using appropriate recovery methods that correspond to the strength of the stressors. Recovery is referred to as “an inter-individual and intra-individual multi-level (e.g.,psychological, physiological, social) process in time for the re-establishment of performance abilities. Recovery includes an action-oriented component, and those selfinitiated activities (proactive recovery) can be systematically used to optimize situational conditions and to build up and refill personal resources and buffers” (Kellmann and Kallus, 2001). It has been pointed out that the root cause of psychological problems caused by chronic stress is insufficient recovery, rather than stress (Kellmann, 2002).