RESULTS AND DISCUSSION
This study evaluated the behavior of salivary cortisol levels during a
long CrossFit® championship. The initial hypothesis, found in literature
review, is that salivary cortisol levels increase after workouts.
However, this was not demonstrated in this study. Athletes’ saliva
samples were collected in the morning, before the competition (D1A –
15.9 ± 10.3 ng/mL, D2A – 13.2 ± 8.0 ng/mL, and D3A – 13.1 ± 9.9
ng/mL), and immediately after the last workout (D1P – 6.4 ± 6.9 ng/mL,
D2P – 9.6 ± 7.9 ng/mL, and D3P – 7.1 ± 6 , 7 ng/ml). A statistically
significant difference (Figure 1) was found only in D1P compared to D1A,
although data showed a trend of fall in cortisol levels throughout the
day, indicating that the circadian rhythm of cortisol seemed to react as
expected7.
In general, the literature has emphasized that the behavior of cortisol
varies according to the intensity of physical exercise; thus, the higher
the intensity, the greater the need to mobilize amino acids of tissues.
Concurrently, the transportation of cortisol from the extracellular zone
to the liver cell increases, which increases their availability for
further conversion to glucose. In addition, the increased peripheral
destruction of cortisol, the decreased hepatic metabolism rate and the
increased ACTH secretion, mostly derived from the influence of
stress-related mechanisms, also contribute to increased cortisol
secretion during physical exercises7.
Authors, such as Nunes et al.8, demonstrated increases
in cortisol concentrations during endurance, power and hypertrophy
exercise protocols. This increase is related to the intensity of the
physical effort performed; the high metabolic demand of higher efforts
tend to induce higher concentrations of cortisol. The idea that
CrossFit® is considered an extreme exercise program9supports this fact. However, this study’s data showed that the
physiological condition of cortisol behavior was maintained.
Other authors have stated that increased cortisol levels play an
important role in athletes’ performance, ultimately meeting their
physical demands during a long-term
competition10,11,12. Some authors have corroborated
that cortisol increases during recovery, indicating a delay in
post-training cortisol secretion in women13,14.
Georgopoulos et al.15 found that female Olympic
gymnasts showed higher stress response, and their salivary cortisol
showed an inverse relation to fat percentage. However, this study was
conducted with adolescent gymnasts, who were thinner than the Average
female gymnasts at their age, had delayed skeletal maturation, suffered
from amenorrhea, and had a significant reduction in fat mass. This
phenotype probably results from multifactorial events; that is why this
behavior cannot be applied to this study.
Our findings, however, contradict the research studies presented above.
In our study, Figure 1 shows the mean values and confidence intervals
for each concentration of salivary cortisol (ng/mL) at each time on
evaluation days, in the pre and post phase. All athletes presented a
physiological performance contrary to the one expected concerning the
cycle of cortisol after a competition based on salivary cortisol. This
finding may partially result from the behavior of cortisol
secretion/metabolism.
Figure 2 reveals that there was a statistical difference
(p>0.05) in the concentration of salivary cortisol (ng/mL)
between each group of evaluation days.
Figure 1. Mean values and confidence intervals for each
concentration of salivary cortisol (ng/mL) at each time on evaluation
days.