Cortisol, DHEA, and testosterone concentrations in saliva in response to an international powerlifting competition

Abstract

The purpose of this study was to examine salivary cortisol, dehydroepiandrosterone (DHEA), and testosterone responses to the bench press in an international powerlifting competition and to determine whether these salivary hormone concentrations could be used to predict performance. Twenty-six elite athletes (13 females and 13 males) provided saliva samples during the official weighing-in and after the last attempt at the bench press, as well as at baseline on a non-competition day. Performance index was determined with the Wilks formula, which adjusts powerlifting scores according to body mass. Salivary cortisol concentrations were significantly increased in all subjects after the bench press (p < 0.01), whereas DHEA concentrations were significantly increased in women (p < 0.01) but not in men after the bench press. No significant change in testosterone concentrations was observed during the experiment in either men or women, which resulted in a marked decrease in the testosterone/cortisol ratio. The performance index showed no significant correlation with any of the hormone responses to competition. In conclusion, despite the increase in stress adrenocortical hormone responses to an international powerlifting competition, these hormone concentrations alone are not predictors of bench press performance in elite powerlifting athletes.

Keywords::

• Bench press
• cortisol
• DHEA
• physical stress
• sex differences
• testosterone

Introduction

Saliva provides a convenient non-invasive way to determine stress adrenocortical [i.e. cortisol and dehydroepiandrosterone (DHEA)] hormone concentrations in the assessment of hypothalamic–pituitary–adrenal axis activity (HPA activity) in patients and healthy subjects (Laudat et al. 1988; Pervanidou et al. 2007; Osterberg et al. 2009). Given the positive correlations between blood and saliva concentrations at rest and during exercise (cortisol: r = 0.46–0.90, p < 0.05–0.001; DHEA: r = 0.68–0.70, p < 0.001; O'Connor and Corrigan 1987; Port 1991; Del Corral et al. 1994; Paccotti et al. 2005; Cadore et al. 2008), the influence of physical exercise on HPA activity has been investigated using saliva cortisol and DHEA measurements in a number of studies in the field (Cook et al. 1986; Lopez Calbet et al. 1993; Passelergue and Lac 1999; Filaire and Lac 2000; Chatard et al. 2002; Cormack et al. 2008; Elloumi et al. 2008; Filaire et al. 2009). Testosterone has also generally been analyzed in order to calculate the testosterone/cortisol (T/C) ratio, which is an index of the anabolic and catabolic balance (Passelergue and Lac 1999; Elloumi et al. 2008).

Studies in a wide range of sports (e.g. cycling, marathon running, football, handball, rugby, tennis, swimming, and wrestling) have almost all shown increased cortisol concentrations during exercise (Cook et al. 1986; O'Connor and Corrigan 1987; Keizer et al. 1989; Passelergue and Lac 1999; Cormack et al. 2008; Elloumi et al. 2008; Filaire et al. 2009). Cortisol secretion, which also reacts strongly to psychological stress (Pervanidou et al. 2007; Osterberg et al. 2009), increases in response to exercise intensity and duration, as well as to the training level of subjects (Keizer et al. 1989; Snegovskaya and Viru 1993a,b; Passelergue et al. 1995), at least in part to mobilize energy stores. Testosterone secretion varies less during acute exercise (Cook et al. 1986; Passelergue et al. 1995; Passelergue and Lac 1999; Filaire and Lac 2000; Elloumi et al. 2008), and few studies have investigated DHEA responses (Filaire and Lac 2000; Chatard et al. 2002). Some studies, but not all (Chatard et al. 2002), have also shown that cortisol responsiveness to exercise is correlated with the performance level (Snegovskaya and Viru 1993a,b), and both cortisol concentration and the T/C ratio have, therefore, been proposed not only to reflect changes in adrenal and testicular activity but also to predict performance.

It should be noted, however, that only one field study (Passelergue et al. 1995) focused on heavy-resistance exercise. In this study, 13 top-level male athletes (seven national level and six international level) participated in two weightlifting competitions, one official and one simulated. The authors reported no change in salivary testosterone concentrations throughout the competition, nor between the competition and the simulation. Conversely, cortisol concentrations were significantly higher in the competition than in the stimulation, but without a significant change before and after the heavy-resistance exercise. Lastly, the authors reported a correlation between the performance level and the cortisol concentrations, with higher concentrations in international than in national athletes, and the authors concluded that cortisol may be a performance factor in weightlifting.

No work to date has focused on powerlifting, a sport involving more explosive force than weightlifting. Moreover, stress hormone responses have not previously been investigated in women during resistance exercise performed in the field. The aim of this study was thus to examine non-invasively the acute steroid hormone response to the bench press in elite male and female athletes during an official international powerlifting competition and to determine whether salivary hormone concentrations could be accurate predictors of performance.

Materials and methods

Subjects

This study was approved by the Institutional Medical Board of the International Powerlifting Federation (IPF) and conducted during a World Bench Press Championship. The group consisted of 26 adult elite powerlifters, 13 females (body weight, mean ± standard error of the mean (SEM), 62.7 ± 6.0 kg; age, 34.2 ± 2.5 years) and 13 males (body weight, mean ± SEM, 95.8 ± 9.1 kg; age 37.7 ± 2.4 years), participating in the competition. The subjects trained an average of 3–8 times per week and gave written consent to participate in the study after being informed of the nature of the experiments. They were required to refrain from eating, drinking, chewing gum, or brushing teeth for 30 min before saliva sampling.

Protocol

Three saliva samples (about 1.5 ml) were taken according to the following schedule: (1) one sample during the official weighing-in (weighing) on the same day as the competition, i.e. between 10:00 and 11:00 h (all females and four males) or between 14:00 and 15:00 h (nine males); (2) one sample after the three attempts at the bench press (bench press); and (3) one sample on an out-of-competition day [day before (12 females and 12 males) or after (one female and one male)] at the same time of day as the weighing-in for each participant (rest), in order to determine the eventual influence of psychological stress.

Saliva collection and analysis

Saliva was collected using Salitubes (DRG Diagnostic, Marburg, Germany). The Salitubes were promptly stored at 4°C within the hour and at − 20°C within 3 days until analysis. Each sample was frozen, thawed, and centrifuged at least once to separate mucins. Enzyme-linked immunosorbent assays were used for the saliva analyses: cortisol, DHEA, and testosterone (kits from DRG Diagnostics). The analytical sensitivity for cortisol, DHEA, and testosterone was 0.012 ng/ml, 2.2 pg/ml, and 1.9 pg/ml, respectively. Coefficients of variation (inter- and intra-assay) were always < 10%.

Performance

Performance was assessed as the best index calculated with the Wilks formula, which adjusts powerlifting scores for body mass. This validated formula (Vanderburgh and Batterham 1999) is currently used in all IPF competitions to calculate the performance index from the best lift multiplied by a bodyweight coefficient number. When no attempt succeeded, performance was not assessed.

Statistical analysis

Data are presented as mean values ± SEM.

Student's t-test was used to determine whether the performance index differed between the female and male powerlifters. Differences in the hormone measures were statistically analyzed by two-way ANOVA for effects of time of sampling (rest, weighing, and bench press) and gender. When a significant F ratio was observed, a Newman–Keuls multiple comparison test was performed to locate the differences. Correlations between saliva hormone values and the performance index were calculated with Pearson's product-moment correlation test. The null hypothesis was rejected at p < 0.05.

Results

Salivary hormone concentrations during exercise

Cortisol

ANOVA revealed no significant gender effect on cortisol concentrations (Figure 1). In all subjects, cortisol concentrations were significantly changed during the experiment (female: F_2,36 = 13.25; male: F_2,36 = 9.76) with higher cortisol concentrations after the bench press (p < 0.01). Cortisol values in females were significantly (p < 0.01) increased between the rest and the weighing sample.

Figure 1.  Mean ( ± SEM) salivary cortisol, DHEA, and testosterone concentrations in elite female and male athletes on an out-of-competition day (rest), during the official weighing-in (weighing), and after the last attempt at the bench press (bench press). *Significant difference (p < 0.01) vs. rest values for females, ^$significant difference (p < 0.01) vs. rest values for males, and ^¤significant difference between females and males (p < 0.001).

DHEA

ANOVA revealed no significant gender effect on salivary DHEA concentrations. DHEA concentrations were not significantly modified during the experiment in males. However, DHEA concentrations were significantly increased in women (F_2,36 = 5.80, p < 0.01) after the bench press.

Testosterone

Testosterone concentrations in the men were consistently significantly higher than concentrations in the women (F_1,76 = 37.48, p < 0.001). No significant change in testosterone concentrations was observed during the experiment for either men or women.

Hormonal ratios

Compared with the rest ratio, the T/C ratio was significantly decreased in both females and males (female: F_2,36 = 6.38, p < 0.01; male: F_2,36 = 4.55, p < 0.05) at the weighing-in and after the bench press (Table I). In female subjects, compared with the rest ratio there was a significant increase in the DHEA/testosterone ratio after the bench press (F_2,36 = 5.9, p < 0.01), with no significant change in the DHEA/cortisol ratio from the rest value. In male subjects, no significant change in either the DHEA/testosterone or the DHEA/cortisol ratio was found during the experiment.

Table I.  Mean ( ± SEM) salivary T/C, DHEA/testosterone, and DHEA/cortisol concentration ratios in 13 females (F) and 13 males (M) on an out-of-competition day (rest), during the official weighing-in (weighing), and after the last attempt at the bench press (bench press).

Ratio	Gender	Rest	Weighing	Bench press
T/C × 1000	F	29.8 ± 7.6	13.4 ± 3.9*	5.1 ± 0.9*
	M	131.3 ± 44.0	32.0 ± 6.5^†	20.5 ± 8.2^†
DHEA/testosterone	F	7.3 ± 2.4	13.6 ± 3.0	21.1 ± 3.1*
	M	4.9 ± 1.0	7.9 ± 2.9	7.9 ± 2.2
DHEA/cortisol × 1000	F	175.6 ± 55.6	179.7 ± 63.8	116.7 ± 35.0
	M	208.3 ± 58.3	200.4 ± 75.8	109.1 ± 35.8

* Significant difference for females (p < 0.01) during the experiment

^† significant difference for males (p < 0.05) during the experiment.

Performance and correlation with hormone responses

In all, two women and three men were unsuccessful at all three powerlifting attempts. The performance index was determined after removing these five subjects, and this index was significantly higher in men than in women (t-test: male: 158.0 ± 6.1, mean ± SEM, n = 10; female: 125.8 ± 5.2, n = 11; p < 0.05). The performance index was not significantly correlated with salivary cortisol, DHEA, or testosterone concentrations, whatever the time of sampling, i.e. on the out-of-competition day, during the official weighing-in, or after the last attempt at the bench press.

Discussion

The major result of this study was the increased stress adrenocortical hormone responses of elite athletes to the bench press in an international powerlifting competition, although these salivary concentrations alone did not predict performance.

A sharp increase in basal salivary cortisol concentrations was observed after the bench press in both the male and female elite athletes, reflecting striking physical stress. This finding agrees with the reports of most studies conducted in the field, which have demonstrated similar increases in cortisol secretion (Cook et al. 1986; O'Connor and Corrigan 1987; Keizer et al. 1989; Passelergue and Lac 1999; Cormack et al. 2008; Elloumi et al. 2008; Filaire et al. 2009) triggered by the exercise intensity threshold. The exact magnitude of the response may depend on the additional stimuli of exercise duration and the possibility of mobilizing hormone synthesizing reserves (Keizer et al. 1989; Snegovskaya and Viru 1993a,b; Passelergue et al. 1995). In addition, we found a significant increase in salivary cortisol concentrations before competition in the female athletes which may reflect anticipation stress (Filaire et al. 2009). This phenomenon was not detected in the men, however, nor with the other hormones.

Only a few studies have investigated DHEA secretion patterns during competitive sport (Filaire and Lac 2000; Chatard et al. 2002), and the physiological role of DHEA during exercise remains poorly understood. In the present study, we found a significant increase in basal DHEA values after the bench press in our female athletes but not in the men. Insofar as the increase in the men's post-exercise salivary DHEA level did not reach significance, one might hypothesize that HPA activation in response to competition was more marked for the elite female athletes than for the male athletes. However, the strong effect of circadian variation in adrenal steroidogenesis may underlie this difference. It was not possible to test all subjects at exactly the same time of day during this international competition because of the different weighing schedules. Although all 13 women were tested at the same time of day, there was greater variability in the timing of testing the men, with four tested at the same time in the morning as the women and the nine others tested later in the day. Hence, a likely explanation of the evidently lower DHEA response in the elite male athletes than in the females is circadian variation in HPA axis activity.

In agreement with previous research (Passelergue et al. 1995; Passelergue and Lac 1999; Filaire and Lac 2000; Elloumi et al. 2008), no change in salivary testosterone level was found in either men or women during the study. This resulted in a significant increase of the rest DHEA/testosterone ratio in female athletes after the bench press, and in a significant decrease of the rest T/C ratio in both female and male athletes at weighing-in and after the bench press, which is considered by some authors as a catabolic phase (Passelergue and Lac 1999; Elloumi et al. 2008).

Using a classic validated performance index, we did not find any significant correlation between performance and salivary hormone concentrations. This finding conflicts with previous studies (Snegovskaya and Viru 1993a; Passelergue et al. 1995). Indeed, Snegovskaya and Viru (1993a) reported that an improvement in the performance capacity of previously trained athletes was associated with elevated cortisol levels during supramaximal exercise. Similarly, Passelergue et al. (1995) reported higher cortisol level during competition in international than in national athletes, with a significant correlation (r = 0.67; p < 0.05) between performance and cortisol concentrations. This was not the case here, perhaps because all of our subjects were elite international athletes. Moreover, although acute salivary cortisol, DHEA, and testosterone concentrations did not predict bench press performance, these parameters might be useful to monitor intra-individual progress, as reported by Snegovskaya and Viru (1993a).

In conclusion, despite the increase in salivary adrenocortical stress hormone levels during an international powerlifting competition, these hormonal concentrations alone cannot be used to predict bench press performance in elite powerlifting athletes. Further work is needed to determine the intra-individual changes in salivary steroid concentrations and performance. Moreover, further field studies exploring the stress hormone responses to the two other disciplines of powerlifting, i.e. the squat and deadlift, are also necessary to extend the present results.

Acknowledgements

This work was carried out with the support of the International Powerlifting Federation. The investigators wish to express their gratitude to the subjects for their dedicated performance. In addition, they likewise thank the referees, the coaches, Alain Lacheze, and Cathy Carmeni for their expert assistance.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.