2013. Vol.4, No.7, 613-618
Published Online July 2013 in SciRes (
Copyright © 2013 SciRes. 613
Elite Sport and Biological Age
Influence of Extensive or Regular Low to Moderate Exercise on Plasma DHEA-S
and Cortisol in Ice-Hockey Players
Benny Johansson1, Lars-Eric Uneståhl2
1Scandinavian International University, Örebro, Sweden
2Örebro University, Örebro, Sweden
Received April 21st, 2013; revised May 23rd, 2013; accepted June 22nd, 2013
Copyright © 2013 Benny Johansson, Lars-Eric Uneståhl. This is an open access article distributed under the
Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any
medium, provided the original work is properly cited.
Based on common comments that elite players in soccer and ice-hockey often looked “older” than non-
players of the same age, the authors examined the research literature but found that very few studies had
been conducted in the area of elite sport and biological age. We therefore decided to conduct a pilot study
comparing professional elite ice hockey players (EP) (22 males, M = 24.7 years) with a cohort of amateur
players (AP) similar in age but from a lower competitive level (17 males, M = 25.4 years). Subjective
ratings of motivational, attitude and emotional factors were combined with measurements of blood con-
centrations of DHEA-S, cortisol and the DHEA-S/cortisol ratio. DHEA-S and the DHEA-S/cortisol ratio
were significantly higher (p < 0.01) while cortisol was unaffected in the AP compared with the EP group.
Interpretation of the differences in adrenal hormones level indicated a biological age difference of around
10 years, with the EP group being older. Also, significant differences in the subjective ratings were noted
with a more positive self-image, goal-image, attitude and emotions noted in the AP-group. As we have
earlier demonstrated a decrease in biological age with mental training of these factors, further studies
have to determine how much the higher biological age among the EP-group is due to exercise factors, ex-
periential/personal factors or a combination of these and other factors.
Keywords: Competitive Sport; Biological Age; Stress; Adrenal Hormones; Emotional Factors; Lifestyle
The process of biological aging goes faster in elite athletes
compared with athletes from a lower level.
If so, the difference in biological age depends on a combina-
tion of factors, of which two have been investigated in this
1) The frequency and intensity of the physical training
(physical stress);
2) How differences in physical and mental stress levels effect
psychological and personality dimensions with relations to bio-
logical age.
Many studies have been conducted to determine the health
effects of physical exercise and competitive sport (Blair, Cheng,
& Holder, 2001; Kriska, Saremi, Hanson, Bennett, Kobes, Wil-
liams, & Knowler, 2003; Pate, Pratt, Blair, Haskell, Macera,
Bouchard, Buchner, Ettinger, Heath, King, Kriska, Leon, Mar-
cus, Morris, Paffenbarger, Patrick, Pollock, Rippe, Sallis, &
Wilmore, 1995; Fogelholm, Kaprio, & Sarna, 1994; Haskell,
Lee, Pate, Powell, Blair, Franklin, Macera, Heath, Thompson,
& Bauman, 2007), but the “dose-response” as well as type,
optimal intensity and duration of exercise for wellbeing and
good health remains unclear (Blair, LaMonte, & Nichman,
2004; Kesaniemi, Danforth, Jensen, Kopelman, Lefebvre, &
Reeder, 2001). Statistics of longevity of elite athletes from
sport have been difficult to find and the few found show con-
flicting results (Schnor, 1971; Schnor, 1972; Kujala, Tikkanen,
Sarna, Pukkala, Kaprio, & Koskenvou, 2001; Kujala, 2005;
Paffenbarger, Hyde, Wing, & Hsieh, 1986; Sanchis-Gomar,
Olaso-Gonzales, Corella, Gomez-Cabrera, & Vina, 2011). Sev-
eral studies confirm that physical and cardiorespiratory fitness
and healthy life style factors contribute to increased average
longevity even at long-term strenuous exercise (Fogelholm,
Kaprio, & Sarna, 1994; Sanchis-Gomar, Olaso-Gonzales,
Corella, Gomez-Cabrera, & Vina, 2011; Lee, Artero, Sui, &
Blair, 2010). One explanation of the contradictory results could
be that the relation between health levels and competitive sport
levels may be described as an inverted U-form relation, where
too little and too much may lower health levels compared with
a moderate level.
Physical exercise and the influence of emotional and psy-
chological stress are significant stimuli of the endocrine system.
The hypothalamus, pituitary and adrenal glands (HPA-axis)
play a central role in the body’s adaptation to stress-related
responses (Faredin, Fazekas, Toth, & Juslesz, 1969; Parker,
Eugene, Farber, Lifrak, Lai, & Juler, 1985). The typical hor-
mone stressors are of physical, emotional, psychological and
infectious nature depending on type, intensity, and duration of
the stressor and individual characteristics (Endoh, Kristiansen,
Casson, Buster, & Hornsby, 1996). The hormonal response to
physical exercise depends on several external factors, e.g. in-
tensity, duration and mode of exercise (Galbo, Hummer,
Petersen, Christensen, & Bie, 1977; Sutton, Coleman, Casey, &
Lazarus, 1973; Trembaly, Copeland, & Van Helder, 2004). The
regulative response of the HPA-axis towards environmental
changes and challenges also involves perceptual and cognitive
experiences (Endoh, Kristiansen, Casson, Buster, & Hornsby,
The most important and abundant stress hormone is cortisol
(Parker, Eugene, Farber, Lifrak, Lai, & Juler, 1985). The secre-
tion of adrenal cortisol in response to stress activation is in a
counteracted manner related to the level of dehydroepiandros-
terone sulfate (DHEA-S) (Orentreich, Brind, Rizer, & Vogel-
man, 1984). The blood concentration of DHEA-S and its pri-
mary active analogue dehydroepiandrosterone (DHEA) (Le-
owattana, 2001) reflects the biological conditions of acute and
chronic stress (Kroboth, Salek, Pittenge, Fabian, & Frye, 1999;
Boudarene, Legros, & Timsit-Berthier, 2002). Falling concen-
trations have been observed in both mental and psychological
stress and physical illness (Boudarene, Legros, & Timsit-
Berthier, 2002). The adrenal secretion and blood concentration
follows a biphasic time course during lifetime, peaking in the
range of 20 - 30 years (Barrett-Conner, Khaw, & Yen, 1986;
Baulieu, 1996; Corrigan, 2002). Thereafter, the blood concen-
tration is declining by a small percentage yearly (Baulieu, 1996;
Wisniewski, Hilton, Morse, & Svec, 1993).
Extensive physical load during marathon in male athletes
demonstrated that DHEA-S and cortisol were significantly
increased (Ponjee, De Rooy, & Vader, 1994). During endurance
training, DHEA-S increased in a dose-dependent manner at
repeated running sessions for two hours. Cortisol was declined
at all running sessions except at two hours, where the response
was increased. The ratio of DHEA-S to cortisol was greater at
rest and shorter running than at longer runs (Tremblay, Cope-
land, & Van Helder, 2005). Plasma DHEA was reported to
increase with exercise, depending on the level of performance
and intensity of the exercise (Cumming & Rebar, 1985; Valaido,
Pantaleoni, & Valeiro, 1991). During 24 h running in men,
DHEA-S, was increased over the course of 24 h, while falling
level in DHEA-S may be possible using continuous aerobic
exercise (Shimizu, Imanishi, Sugimoto, Takeda, Hirata, Andou,
Morikawa, Suzuki, Watanabe, Okuta, Kawana, Namikawa,
Suzuki, Watanabe, Okada, & Oht, 2011). Even though, cortisol
was increased, changes in reactive oxygen spices were within
normal range and the adaptation for antioxidation was good,
indicating low or moderate stress to the body. In marathon run-
ners, lowered cortisol and higher DHEA-S/cortisol ratio corre-
lated with lowered leptin and thus more efficient energy expen-
diture for the best runners (Bobbert, Mai, Brechtel, Schult,
Weger, Pfeiffer, Spranger, & Diederich, 2012). Evaluated from
two separate independent studies, the plasma DHEA-S differs
by approximately 14% when compared between endurance
trained (Tremblay, Copeland, & Van Helder, 2005) and un-
trained (Nafziger, Bowlin, Jenkins, & Pearson, 1998) men at
comparable age (31 years), the extensively trained men being
lower at rest. The exercise in the trained men increased the
DHEA-S in a dose-response manner with the greatest increase
observed during 2 h run, comparable to the normal plasma level
in untrained men.
In sportswomen, the ratio of DHEA to cortisol in saliva was
increased by more than 30% during a 16 week training pro-
gram with no difference between highly trained national and
moderately trained regional groups. The athletes with the high-
est performance levels and greatest amount of training showed
a less increase in the DHEA/cortisol ratio In contrast, the cor-
responding ratio was significantly lower in sedentary women
(Filaire, Duch, & Lac, 1998). Cortisol did not change with the
training over the season and was higher in the elite than in re-
gional women. The training program increased significantly
DHEA in all sportswomen.
In non-athletes, increased plasma DHEA-S has been con-
nected with alleviated chronic stress-load (Glaser, Brind, Vo-
gelma, Eisner, Dillbeck, Walace, Chopra, Orentreich, 1992;
Arlt, Callies, van Vlijmen, Koehler, Reinecke, Bidlingmaier,
Huebler, Oettel, Ernst, Schulte, & Allolio, 1999), positive
measures of well-being (Cawodd, & Bancroft, 1996), continued
moderate physical activity (Keiser, Kuipers, de Haan, Beckers,
& Habets, 1987; Caciarri, Mazzanti, Tassinar, Bergamaschi,
Magnani, Zappulla, Nanni, Cobianchi, Ghini, Pini, & Tani,
1990) and repetitive application of stress-reducing and relaxa-
tion activities (Glaser, Brind, Vogelma, Eisner, Dillbeck, Wal-
ace, Chopra, & Orentreich, 1992; Johansson, & Uneståhl,
The aim of this study was to compare elite with amateur ice-
hockey players on cognitive and emotional issues and on the
integrity of the HPA-axis by assessing the level of the adrenal
hormones DHEA and cortisol in order to relate this to biologi-
cal age.
Subjects and Methods
The purpose of this study was to monitor the effect of exten-
sive or low to moderate training for two teams of male ice-
hockey players, on blood concentrations of DHEA-S and corti-
sol, the DHEA-S/cortisol ratio and on experiential areas. Sub-
jective data were collected from the SMAE factor questionnaire
(Unestahl & Bundzen, 1996), which measures self-image,
goal-Images, attitude and emotions.
One team consisted of highly-trained elite players, playing
on national level, while the second team was a low to moderate
trained regional ice hockey team. In accordance with previous
presented research findings, the blood concentration ratio of
DHEA-S/cortisol could serve as a biochemical marker and
model for the anabolic/catabolic balance in sportsmen (Adler-
creuts, Hakonen, Kuoopasalami, Naveri, Huhtanemi, Tikkanen,
Remes, Dessypris, & Karvonen, 1986) with relation to biologi-
cal age and to physiological and psychological well-being
(Johansson & Uneståhl, 2005).
A group of 39 healthy male volunteers took part in the study;
22 national and 17 regional ice-hockey players. The Elite Play-
ers (EP) had an average age of 24.7 years (19 - 33) and the
amateur players (AP) averaged at 25.4 years (17 - 35). The EP
group consisted of professional ice-hockey players, whereas the
players in the AP group were amateur players with ordinary
labour work during daytime. None of the participants were
taking medication. Both groups were lead by professional
coaches. The study was done during the second part of the
winter season. All subjects in the EP group were on daily
scheduled individual and team-based extensive training pro-
Copyright © 2013 SciRes.
gram except on match days and remained unchanged during the
study. The training program during non-match days, comprised
of two daily sessions of two hours each. Long-distance and
exhausting continental bus transfers provided the transportation
of the professional team players away from home competitions.
Two competition games were performed on regular weekly
basis during the season.
The players in the AP group followed a low or moderate
training and competition program. Scheduled training was per-
formed twice weekly for two hours and a competition game
only once a week. Due to the local character and short-distance
of transportation at competitions, co-transportation of team
players was done by car. The content of the study protocol fol-
lowed the recommendations of the local committee of human
ethics. Each subject was informed of the test procedures and a
written consent was obtained before study start.
Subjective Measures
Subjective self-reported measurements were made with the
Swedish “SMAK” test, measuring the dimension: Self-image
(S), Goal-images and Motivation (M), Attitudes (A) and Emo-
tions (K). The Test was developed by Unestahl in the 1970’s in
cooperation with a number of national teams and the Swedish
Olympic Teams 1976 and 1980. It has been used in a number of
studies since then, among other in our last study about biologi-
cal age (Johansson & Uneståhl, 2005). The test has good reli-
ability and validity.
The S-factor (Self-Image) has statements related to Self-con-
fidence as well as Self-esteem. The Goal-Images covers both
Goal-level and Motivation. The Attitude scale has statements
related to the Optimist—Not Optimist dimension, and also
statements about Mental toughness and Resilience. The “E”
factor is intended to measure “Internal Success” (transitory
feelings of satisfaction, enjoyment, wellbeing and happiness).
Changes in the SMAE factors through Mental Training have
earlier been related to a number of psychophysiological and
neuroimmunological factors (Johansson & Uneståhl, 2005;
Unestahl & Bundzen, 1996; Bundzen, Leissner, Malinin, &
Unestahl, 1996; Unestahl, Bundzen, Gavrilova, & Isakov, 2004;
Bundzen, Gavrilova, Isakov, & Unestahl, 1998).
Collection of B lood and Analysis of Stero i d Hor mo nes
Venous blood samples were collected in the morning in
Vacutainer® tubes and 5 ml of blood were drawn for each sam-
ple. Blood samples were centrifuged immediately and stored
frozen at –20˚C until assayed. All plasma samples were ana-
lysed in duplicate at an accredited local hospital department of
clinical chemistry, according to standard laboratory methods for
DHEA-S and cortisol (Beishuizen, Thijs, & Vermes, 2002;
Normile, 1998; Labrie, Bélanger, Cusan , Gomez, & Candaz,
Statistical Analysis
All descriptive quantitative data were reported as mean ± SD.
Comparisons between groups were made by unpaired student’s
t-test, while a two-tailed p value < 0.05 was considered as sta-
tistical significant.
Mean plasma DHEA-S, cortisol and the ratio of DHEA-S/
cortisol for the EP and AP groups are given in Figures 1-3,
respectively. The plasma concentration of DHEA-S in the EP
group was significantly lower (<0.01) compared to the AP-
group (Figure 1). The level of plasma cortisol was the same in
both groups (Figure 2). The ratio of DHEA-S to cortisol was
significantly higher in the EP-group compared with the AP
group (p < 0.01), indicating elevated catabolism in professional
players with sustained anabolism in amateurs (Figure 3). In the
SMAE factor test all personal subjective factors were found to
have significantly more positive ratings in the amateurs (AP);
Plasma concentration of DHEA-S (μmol/l)
Figure 1.
Plasma concentration of DHEA-S (Mean ± SD) in the EP and LP
groups (**p < 0.01).
Plasma concentration of Cortisol (nmol/l)
Figure 2.
Plasma concentration of cortisol (Mean ± SD) in EP and LP
Ratio of plasma concentration of DHEA-S and
Figure 3.
Plasma concentration of the DHEA-S/cortisol ratio (Mean ± SD)
in the EP and LP groups (**p < 0.01).
Copyright © 2013 SciRes. 615
Self-image (p = 0.008), Goal images (p = 0.023), Attitudes (p =
0.032), and Emotions (p < 0.001) (Table 1). Thus, in profes-
sionals the response of the HPA-axis followed the level of
physical exercise reflected in a concomitant emotional and
cognitive stress load.
The 33% higher plasma DHEA-S in the AP group corre-
sponds to a difference in biological age that according to nor-
mal reference observations is approximately 10 years below the
average age range in the EP-group. The subjective ratings
showed that the amateur ice-hockey players (AP) had signifi-
cantly better self-images, were more goal-oriented and moti-
vated, were interpreting life in a more positive way and had
more of positive emotions. Whether, the difference in biologi-
cal age was mainly due to exercise levels or cognitive and emo-
tional factors or a combination of these cannot be directly de-
termined based on this study. We know from an earlier study
(Johansson & Uneståhl, 2005) that mental training of cognitive
and emotional factors can raise the DHEA-S/Cortisol ratio (thus
suggesting a lowering of the biological age). We also know
from a previous study (Unestahl, Bundzen, Gavrilova, & Isakov,
2004) that systematic mental training can increase the tolerance
for hard training and prevent the negative effects of “overtrain-
ing”, partly due to improved rest and recovery skills. Thus, one
contributing explanation of the results of our study could be
that the lower intensity of training and matches in the amateur
players gave them more time for rest and recover. The plasma
DHEA-S and DHEA-S to cortisol ratio were concomitantly
higher in the AP group, in spite of no difference in the plasma
cortisol between groups.
Thus, the lower DHEA-S and the lower DHEA-S to cortisol
ratio together with less positive subjective emotional experi-
ences among the elite players, agrees with the negative influ-
ence of lowered levels of these hormones on both psychological
and physiological, physical performance and health outcome
(Endoh, Kristiansen, Casson, Buster, & Hornsby, 1996).
Since the HPA axis is influenced by psychological, emo-
tional or physical stress (Faredin, Fazekas, Toth, & Juslesz,
1969; Parker, Eugene, Farber, Lifrak, Lai, & Juler, 1985;
Duran-Bush, Faubert, & Newburg, 2004); Singh, Petrides, Gold,
Chrousos, & Deuster, 1999), DHEA-S has been identified as an
anti-stress hormone related to the antagonistic action towards
cortisol (Boudarene, Legros, & Timsit-Berthier, 2002). The
counteracting inter-balanced secretion towards stress and anxi-
ety of the most numerous androgen DHEA-S has been a sug-
gested force on experience of the positive feeling of wellbeing
(Orentreich, Brind, Rizer, & Vogelman, 1984, Boudarene,
Legros, & Timsit-Berthier, 2002; Normile, 1998). Tentatively,
DHEA-S is involved in conditioning of an emotional state
based not only on improved wellbeing and external suc-
cess(Glaser, Brind, Vogelma, Eisner, Dillbeck, Walace, Chopra,
Orentreich, 1992; Cawodd & Bancroft, 1996; Johansson &
Table 1.
SMAE personal trait factors in ice-hockey players.
Goal-image* Self-image’** Attitude*** Emotion#
2.9 ± 0.5
2.4 ± 0.5
2.2 ± 0.4
1.9 ± 0.35
2.1 ± 0.4
1.7 ± 0.4
1.9 ± 0.4
1.6 ± 0.5
Note: *p = 0.008; **p = 0.024; ***p = 0.032; #p = 0.001.
Uneståhl, 2005), but a shift in personal traits aligned with a
comfortable attitude towards life-experiences and events built
on high emotional internal self-residence.
The results indicate that the amateurs are more adapted to a
resonance state in a process that allows the individuals to feel
the way they want to feel. Such a state of self-development
underlies how to make meaning of daily experiences, and is
reflected in the success of planning, thinking, and acting (Lo-
evinger, 1976; Loevinge, Cohn, Bonneville, Redmore, Streich,
Bonneville, Redmore, Streich, & Sargent, 1985; Cook-Greuter,
1999). The process is typically experienced as a seamless fit or
harmony between the individual and the environment (Duran-
Bush, Faubert, & Newburg, 2004).
The unchanged plasma cortisol between groups at restful
conditions in the morning before the daily physical exercise
begun accompanied with the decrease in the DHEA-S/cortisol
ratio in professionals, agrees with findings after moderate
physical exercise, which even lead to an increase in plasma
cortisol when the exercise was intensified (Adlercreuts,
Hakonen, Kuoopasalami, Naveri, Huhtanemi, Tikkanen, Remes,
Dessypris, & Karvonen, 1986; Trembaly, Copeland, & Van
Helder, 2004). Prolonged over-intense training may lead to an
over-strained condition, which may involve mental exhaustion,
emotional discomfort and hormonal disturbance in the balance
between anabolic and catabolic hormones. Continuing the phy-
sical training with unchanged intensity will in such a case have
negative effects on physical performance (Adlercreuts, Hakonen,
Kuoopasalami, Naveri, Huhtanemi, Tikkanen, Remes, Dessy-
pris, & Karvonen, 1986). A study monitoring over-strain in two
groups of long-distance runners, identified physiological over-
strain from the plasma testosterone/cortisol ratio when it was
exceeding 30% (Adlercreuts, Hakonen, Kuoopasalami, Naveri,
Huhtanemi, Tikkanen, Remes, Dessypris, & Karvonen, 1986).
Besides testosterone, other anabolic hormones have been tested
monitoring physical overstrain (Adlercreuts, Hakonen, Kuoopa-
salami, Naveri, Huhtanemi, Tikkanen, Remes, Dessypris, &
Karvonen, 1986).
In this regime, DHEA-S is a precursor hormone of more po-
tent androgens involved to restore the consequences of cata-
bolic activity and processes (Nafziger, Bowlin, Jenkins, &
Pearson, 1998). Since DHEA-S is also a balancing hormone
counteracting on the alleviated secretion of cortisol, e.g. after
induction of an physiological state impressed by emotional
comfort and well-being (Glaser, Brind, Vogelma, Eisner, Dill-
beck, Walace, Chopra, & Orentreich, 1992; Johansson &
Uneståhl, 2005), the DHEA-S/cortisol ratio has been used fol-
lowing the physical load in athletes (Ponjee, De Rooy, & Vader,
1994; Trembaly, Copeland, & Van Helder, 2005; Filaire, Duch,
& Lac, 1998). The significant difference in DHEA-S/cortisol
ratio (32.7%) between the two groups in our study was strongly
aliened with the lower rating in especially the subjective emo-
tional measurement in professional ice-hockey players, that
may highlight not only the negative influence of professional
and elite sports on performance, but the risk of future ill-health
(Endoh, Kristiansen, Casson, Buster, & Hornsby, 1996).
The age-dependence of plasma DHEA-S and its precursor
DHEA, and the proposed preventive and anti-aging effects
including their role as biomarkers of physiological aging has
been debated and questioned (Kroboth, Salek, Pittenge, Fabian,
& Frye, 1999; Shimizu, Imanishi, Sugimoto, Takeda, Hirata,
Andou, Morikawa, Suzuki, Watanabe, Okuta, Kawana, Nami-
kawa, Suzuki, Watanabe, Okada, & Oht, 2011). Studies have
Copyright © 2013 SciRes.
shown that stress and serious disease are associated with a shift
from secretion of androgens towards glucocorticoids (Cook-
Greuter, 2000). This can mainly be seen as increased plasma
cortisol and lower DHEA-S (Corrigan, 2002).
Additionally, a decrease in the DHEA/cortisol ratio and low
DHEA-S has been correlated with the suppression of cellular
immunity and the severity of disease (Parker & Odell, 1980).
The average age-dependent decline in plasma DHEA-S con-
centrations differed significantly by a few % per year by sex
and age group (Baulieu, 1996; Wisniewski, Hilton, Morse, &
Svec, 1993; Nafziger, Bowlin, Jenkins, & Pearson, 1998). The
falling concentration in DHEA-S related to level of mental and
physiological stress and physical illness (Boudarene, Legros, &
Timsit-Berthier, 2002) support the hypothesis that those sub-
jects with lower DHEA-S has a shorter life-span (Baulieu,
A common belief with so far limited support by research, is
that elite athletes especially elite players in team sports, have a
shorter life span than other human beings (Ruiz, Moran, Arenas,
& Lucia, 2010). The thrifty of longevity research show con-
flicting results, where long-distance runners and cross-country
skiers (Kujala, Tikkanen, Sarna, Pukkala, Kaprio, & Kosken-
vou, 2001; Kujala, 2005) and Tour de France cyclists (Sanchis-
Gomar, Olaso-Gonzales, Corella, Gomez-Cabrera, & Vina,
2011) had increased longevity, while individuals with weekly
energy expenditure in the range of 3500 kcal show a mortality
rate higher than the sedentary population (Paffenbarger, Hyde,
Wing, & Hsieh, 1986). A less effective energy expenditure
gains a stress induced anabolic hormonal response with in-
creased leptin values in over-strain athletes (Bobbert, Mai,
Brechtel, Schult, Weger, Pfeiffer, Spranger, & Diederich,
2012r), a plausible longevity risk factor.
In conclusion our findings indicate that the lower DHEA-S
level and DHEA-S/Cortisol ratio among the professional elite
players correspond to a biological age around 10 years older
than the amateur players. In addition to that the amateur ice
hockey players rated themselves as more confident, goal-ori-
entated, motivated and optimistic and with more positive
moods and feelings than the professionals. Whether these expe-
riential differences are a result mainly from the training levels
or hormonal differences should be investigated in future re-
Other proposals for further research besides doing similar
investigations as ours in other sport, (team- and individual-
sports) could be to investigate the longevity of athletes in dif-
ferent sports and from different levels of physical activity and
psychological distress.
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