monitoring stress tolerance and occurrences of upper respiratory illness in basketball players by...

e166 Stress and Health 27: e166–e172 (2011) © 2010 John Wiley & Sons, Ltd.

RESEARCH ARTICLE

Monitoring Stress Tolerance and Occurrences of Upper Respiratory Illness in Basketball Players by Means of Psychometric Tools and Salivary BiomarkersAlexandre Moreira1*†, Franco Arsati2, Ynara Bosco de Oliveira Lima-Arsati2, Antonio Carlos Simões1 & Vera Cavalcanti de Araújo3

1Department of Sport, School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil2Department of Physiological Sciences, São Leopoldo Mandic Dental Research Center, Campinas, Brazil3Department of Oral Pathology, São Leopoldo Mandic Dental Research Center, Campinas, Brazil

Abstract

The aim of the study was to evaluate the possible relationships between stress tolerance, training load, banal infec-

tions and salivary parameters during 4 weeks of regular training in fi fteen basketball players. The Daily Analysis of

Life Demands for Athletes’ questionnaire (sources and symptoms of stress) and the Wisconsin Upper Respiratory

Symptom Survey were used on a weekly basis. Salivary cortisol and salivary immunoglobulin A (SIgA) were col-

lected at the beginning (before) and after the study, and measured by enzyme-linked immunosorbent assay (ELISA).

Ratings of perceived exertion (training load) were also obtained. The results from ANOVA with repeated measures

showed greater training loads, number of upper respiratory tract infection episodes and negative sensation to both

symptoms and sources of stress, at week 2 (p < 0.05). Signifi cant increases in cortisol levels and decreases in SIgA

secretion rate were noted (before to after). Negative sensations to symptoms of stress at week 4 were inversely and

signifi cantly correlated with SIgA secretion rate. A positive and signifi cant relationship between sources and symp-

toms of stress at week 4 and cortisol levels were verifi ed. In summary, an approach incorporating in conjunction

psychometric tools and salivary biomarkers could be an effi cient means of monitoring reaction to stress in sport.

Copyright © 2010 John Wiley & Sons, Ltd.

Received 29 March 2010; Accepted 13 August 2010; Revised 13 June 2010

Keywords

salivary immunoglobulin A; salivary cortisol; sports; immune function; hypothalamic-pituitary-adrenal axis; psychological stress

*Correspondence

Alexandre Moreira, Av. Prof. Mello de Moraes, 65—Cidade Universitária, CEP 05508-030, São Paulo, SP, Brazil.†Email: [email protected]

Published online 5 October in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/smi.1354

Introduction

An accumulation of stress in athletes must be consid-

ered in both a sport and a non-sport environment. The

necessity of utilizing markers to monitor these reac-

tions in a practical setting is evident. Even recognizing

that the physiological stress could be considered as the

most important cause of distinct syndromes as non-

functional overreaching and overtraining (Nederhof,

Lemmink, Visscher, Meeusen, & Mulder, 2006), early

insights pointed toward the combination with the

psychological and/or social stressors in relation to

regeneration (Hooper & Mackinnon, 1995; Kentta &

Hassmen, 1998; Lehmann, Foster, & Keul, 1993).

Budgett (1990) suggested that only a small increase

in the total stress (considering the stressors with dis-

tinct categories), in addition to the physiological stress

(by training), might induce what the author named

Stress and Health 27: e166–e172 (2011) © 2010 John Wiley & Sons, Ltd. e167

A. Moreira et al. Monitoring Stress in Basketball Players

‘staleness’ that is a term also used for the ‘overtraining

syndrome’ or just ‘overtraining’, especially in the Euro-

pean literature (Nederhof et al., 2006).

Salivary cortisol, as a representative of circulating

free cortisol has been recommended as an index of

training stress (Passelergue & Lac, 1999) and its use has

also been adopted because this avoids the stress caused

by venepuncture (Lac, Lac, & Robert, 1993) and refl ects

the free plasma concentration and bioactive compo-

nent of steroid hormones. In addition, salivary cortisol

levels parallel those in plasma following adrenocorti-

cotropic hormone and corticotropin-releasing horm-

one stimulation, and following exercise induced-stress

(Gozansky, Lynn, Laudenslager, & Kohrt, 2005; Vining,

McGinley, Maksvytis, & Ho, 1983). Vining et al. (1983)

also suggested that salivary cortisol may actually provide

a better measure of the stress response than serum cor-

tisol as it more accurately measures the amount of

unbound cortisol compared to serum measurements.

It has also been proposed that an increased secretion

of glucocorticoids could induce depression of immune

cell functions (Fleshner, 2000). Wira, Sandoe, and

Steele (1990) demonstrated that the potent synthetic

glucocorticoid dexamethasone causes a decline in the

salivary immunoglobulin A (SIgA) concentration 24 h

after a single injection. SIgA is the most commonly

studied marker of the mucosal immune system (Bishop

& Gleeson, 2009).

The athletes’ vulnerability to respiratory tract infec-

tions is one of the features of most interest to researchers

of different disciplines. Recently, Martin, Pence, and

Woods (2009) provided evidence to support the

increased susceptibility to upper respiratory tract infec-

tions (URTI) with chronic stressors with their research

in mice, which is consistent with the observational data

regarding exercise and illness incidence in humans. For

example, Neville, Gleeson, and Folland (2008) recently

showed a signifi cant reduction (28%) in SIgA occurring

during the 3 weeks before URTI episodes and returned

to baseline 2 weeks after an URTI. When an athlete did

not have, or was not recovering from URTI, a SIgA value

lower than 40% of their mean healthy SIgA concentra-

tion indicated a 50% chance of contracting an URTI

within 3 weeks. In addition, the authors affi rm that the

relationship between physiological and psychological

stress and immune function is widely recognized.

The necessity of monitoring URTI episodes that

could be associated to stress tolerance and might impair

performance by means of simple tools is evident. Unfor-

tunately, there is relatively little research with valid,

practical and noninvasive tools to monitor stress state

and URTI episodes with elite young team players. Mon-

itoring changes in sources and symptoms of stress in

team-sports, including its relationship with banal infec-

tions, particularly URTI, may assist coaches to control

appropriately the training process. In addition, the link

between salivary cortisol and SIgA levels with URTI

episodes and stress tolerance needs to be elucidated.

Therefore, the aim of the present study was to evalu-

ate if sources and symptoms of stress as well as the

occurrence of URTIs could be associated with changes

in salivary cortisol and SIgA during a competitive train-

ing period in elite young basketball players. It was

hypothesized that there would be a relationship between

stress tolerance, training load, banal infections and sali-

vary parameters during the investigated training period.

Material and methods

Participants

The sample comprised 15 male basketball players

([mean and standard deviation to age = 19 ± 0.6 years,

height 192 ± 10 cm, body mass 92 ± 9 kg). They com-

menced the observation period in a good health state,

as assessed by a medical screening. None of them were

receiving medication or had suffered from a debilitat-

ing infection in the preceding 2 weeks. They usually

trained for 90–120 min per session, two sessions per

day, and fi ve days per week. The investigated team was

successful reached the second position at the Under-19

State Championship. The investigated athletes also

usually train and/or compete with the main (adult)

team. Their habitual training sessions consisted of one

tactical and technical session, one specifi c conditioning

work as well as weight training and plyometric training.

After being informed of the experimental procedures,

including potential benefi ts and risks, the athletes gave

written consent to participate. The local ethics commit-

tee approval was previously obtained.

Experimental design

The study observations were carried out over a 4-week

period during the competitive season. After these four

investigated weeks, the team was involved in the play-

off matches from the State Championship. Therefore,

the last investigated week could be considered as a

‘taper’ week, with a reduction in both training time and

Monitoring Stress in Basketball Players A. Moreira et al.


training intensity. During the experimental period, they

played one game per week. Ratings of perceived exer-

tion (session-RPE) after each exercise session in each

day throughout 28 days were obtained from all athletes

involved in the study. A Daily Analysis of Life Demands

for Athletes’ questionnaire (DALDA; sources and symp-

toms of stress) and the Wisconsin Upper Respiratory

Symptom survey (WURSS-21) to monitor the symp-

tomatology of URTI were used on a weekly basis. Saliva

samples were collected at the beginning of the study

and one week after the fi nish of the experiment. The

saliva samples were collected at rest, in the afternoon,

at the same time of day both before and after the inves-

tigated period. The recovery interval from the last bout

of exercise was at least 10–12 h. The subjects abstained

from food and caffeine products for 60–90 min prior

to the saliva collection.

Saliva collection

The subjects were in a seated position, with eyes open,

head tilted slightly forward and making minimal oro-

facial movement. Unstimulated saliva was collected

into sterile 15-mL centrifuge tubes over a 5-min period.

Immediately after collection, the saliva samples were

frozen and stored at −80°C until assayed for cortisol

and SIgA concentration.

Assays

Salivary immunoglobulin A concentration was mea-

sured by enzyme linked immunosorbent assay (ELISA,

SIgA EIA kit, ALPCO Diagnostics, Salem, MA, USA) in

accordance with our previous work (Moreira, Arsati,

Cury, et al., 2009; Moreira et al., 2008). The SIgA secre-

tion rate (SIgArate; μg·min−1) was calculated by multi-

plying the absolute SIgA concentration by salivary fl ow

rate (mL·min−1). Salivary fl ow rate was determined by

dividing the volume of saliva collected by the duration

of the sampling period. The cortisol concentration was

also measured by enzyme-linked immunosorbent assay

(ELISA, Cortisol—Direct Salivary EIA; ALPCO Diag-

nostics, Salem, MA, USA) in accordance with our pre-

vious work (Moreira, Arsati, de Oliveira Lima Arsati, da

Silva, & de Araújo, 2009).

Monitoring training load

The training load (TL) for each athlete during each

training session was calculated according to the methods

of Foster (Foster, 1998). This method of monitoring TL

requires each athlete to provide an RPE (CR-10 scale)

for each exercise session along with a measure of train-

ing time. To approach the session intensity, athletes

were asked after 30 min of the end of their workout a

simple question: ‘How was your workout?’ A single

number representing the magnitude of TL for each

session was then calculated by the multiplication of

training intensity by its duration (TL = Session-RPE ×

duration in min).

DALDA

DALDA (Rushall, 1990) was also completed on days 7,

14, 21 and 28 by each athlete. The DALDA is divided

into two parts, namely Part A and Part B, which repre-

sent the sources of life stress and symptoms of stress,

respectively. The athletes were asked rate each item to

‘worse than normal’, ‘normal’ or ‘better than normal’.

The responses ‘worse than normal’ were retained for

analysis. Although it is advised that the DALDA be used

on a daily basis or every other day, it was previously used

on a weekly basis without having its sensitivity dimin-

ished (Robson-Ansley, Blannin, & Gleeson, 2007).

Upper respiratory illness questionnaire

A short version of the WURSS-44, the WURSS-21

(Barrett et al., 2005) was utilized to measure all signifi -

cant health-related dimensions that are negatively

affected to the common cold. It was assumed that the

responses by WURSS-21 would be a reasonable marker

of symptomatology of URTI and functional impair-

ment according to previous studies (Spence et al.,

2005). The WURSS-21 includes 10 items assessing

symptoms, nine items assessing functional impair-

ments and 1 item each assessing global severity and

global change (‘How sick do you feel today?’ and ‘com-

pared to yesterday, I feel that my cold is . . .’). All the

items are responded using a Likert scale of severity,

ranging from 0–7. The total number of occurrences

regardless of severity level was retained for analysis.

Statistical analyses

Data is reported as means and standard error of

the mean (SEM). The distribution of the data was

analyzed by the Shapiro-Wilk test. The Mauchly’s

Test of Sphericity was performed to test the null

hypothesis that the error covariance matrix of the



orthonormalized-transformed dependent variables was

proportional to an identity matrix. An ANOVA with

repeated measures was used to compare the four

moments (week 1, 2, 3 and 4) for each dependent vari-

able. Salivary cortisol and SIgA levels were compared

between week 1 and week 4. Tukey HSD post hoc test

was utilized when necessary. In the case of violation of

the assumption of sphericity, the signifi cance was estab-

lished by utilizing the Greenhouse-Geisser correction.

The relationships between dependent variables were

evaluated by means of Pearson product moment cor-

relation. The level of signifi cance was set at 0.05.

Results

Table I shows the weekly training load measured during

the experimental training period. A signifi cant differ-

ence between the second and the fourth week was

observed (p < 0.05). The values refl ect an average

weekly training load (accumulated diary training load

divided by number of the sessions in each week).

In Table II, the values from absolute SIgA concen-

tration (SIgAabs), SIgA secretion rate (SIgArate) and

salivary cortisol before commencement of the training

and 1 week after the training period are revealed. The

signifi cant increases in cortisol levels and decreases in

SIgArate were verifi ed (p < 0.05; before to after

moments).

Figure 1 illustrates the dynamics of the symptom-

atology of URTI. Signifi cant differences (p < 0.05)

between week 2 to weeks 1 and 4 were verifi ed, reveal-

ing the great number of episodes in week 2.

In Figure 2, the number of responses ‘worse than

normal’ from part A of DALDA, indicates the dynamics

of sources of stress. Signifi cant differences were observed

from week 2 to week 1, 3 and 4 (p < 0.05).

In Figure 3, the number of responses ‘worse than

normal’ from part B of DALDA, indicates the dynamics

Table I. Weekly training load measured during the study period; mean (SEM)

Week 1 Week 2 Week 3 Week 4

Training load 656 (92) 680 (83) 548 (37) 479 (34)*

Training load [Arbitrary units (AU)].

* Signifi cant difference from week 2 (p < 0.05).

Table II. Mean and SEM of SIgAabs, SIgArate and salivary cortisol before and after the investigated training period

Before training

period

After training

period

Salivary cortisol (ng·ml−1) 17.6 (1.8) 26.8 (4.9)*

SIgAabs (μg·mL−1) 587 (94) 720 (153)

SIgArate (μg·min−1) 106 (20) 92 (21)*

Before training period: before commencement of the investigated

training period; after training period: 1 week after the investigated

training period; SIgAabs: absolute SIgA concentration; SIgArate: SIgA

secretion rate.

* Signifi cant difference between before and after training period

(p < 0.05).

Figure 1 Total number of occurrences (symptomatology of upper

respiratory tract illness—responses from WURSS-21). *Signifi cant

difference from week 2 (p < 0.05)

Figure 2 Numbers of responses ‘worse than normal’—Sources of

stress (Part A of DALDA). *Signifi cant difference from week 2

(p < 0.05)

Figure 3 Numbers of responses ‘worse than normal’ Symptoms

of stress (Part B of DALDA). *Signifi cant difference from week 2

(p < 0.05)



of symptoms of stress. Signifi cant differences (p < 0.05)

were observed between week 2 and week 4.

In Table III, only the signifi cant correlations between

dependent variables are presented.

Discussion

The results from the present study showed an interest-

ing perspective to use the DALDA and WURSS-21

questionnaires together with training load to monitor

training. Signifi cant differences between week 2 and

other weeks in sources and symptoms of stress

(DALDA) and URTI symptomatology (WURSS-21)

were revealed.

These results corroborate the assumption of differ-

ent authors considering the importance of monitoring

perceived stress. For example, Kentta and Hassmen

(1998) proposed the onset of staleness is caused by an

increase in psychological and/or social stress, leading to

an inability to recover from a previous physiological

stress. It is important to note that in the present study,

the greater negative responses, represented by the rise

in total occurrences (episodes) of URTI, emerged

during the second week; during this same week, partici-

pants reported the greatest number of responses ‘worse

than normal’ in sources and symptoms of stress dem-

onstrating that social and psychological stress factors in

conjunction with physiological stress (training load)

have a considerable role to the adaptation process.

Indeed, our results are in agreement with the fi nd-

ings from Main and Grove (2009) who reported the

initial validation of a multi-component assessment

model for monitor training distress among athletes.

Moreover, recent developments suggest that the brain

and the peripheral immune system cells form a bidirec-

tional communication network (Quan & Banks, 2007).

Fry, Morton and Keast (1991) proposed some ‘cat-

egories’ with the aim to monitoring training, which

include physiological and psychological dimensions as

well as the biochemical and immunological aspects.

The agreement concerning the data from the question-

naires utilized in the present study reinforces the notion

that the training load in conjunction with the social and

psychological aspects needs to be considered. Indeed,

our results are in accordance with the practical methods

of monitoring and managing fatigue in athletes explored

and proposed recently (Robson-Ansley, Gleeson, &

Ansley, 2009).

In respect of hormonal and mucosal immune param-

eters, the results showed that salivary cortisol levels rose

from before to after investigated training period despite

the signifi cant reduction in training load from the

second to the fourth week. So, it is plausible that not

only the training load but also the psychological factor

were crucial to this alteration. Additionally, it is reason-

able to speculate that these changes in salivary cortisol,

could be linked, at least in part, with the reduction in

SIgArate from before to after moment, considering that

the stress hormone is potent modulators of immune

function.

An inherent drawback of the current study is the

inability to monitor the salivary parameters during all

the investigated weeks, yet they were measured only at

the beginning and end of the training period. All the

other variables were measured each week. Correlations

would have been done over the four time points. Nev-

ertheless, despite of these limitations, the present fi nd-

ings revealed some interesting fi ndings about the

possible association among the investigated psycho-

metrics tolls, hormonal and mucosal immune param-

eters in team-sports, as well as the usefulness of this

approach to monitor training.

Table III. Signifi cant correlations between dependent variables (p < 0.05)

Pearson correlations (r) Symptomatology of

URTI—week 2 (WURSS-21)

Before—Salivary cortisol After—Salivary cortisol Before—SIgArate

Sources of stress week 2

(DALDA—Part A)

0.79

Symptoms of stress week 2

(DALDA—Part B)

0.65

Symptoms of stress week 4

(DALDA—Part B)

0.67 0.75 −0.73

Before: before commencement of the investigated training period; After: 1 week after the investigated training period.

DALDA: The Daily Analysis of Life Demands for Athletes’ questionnaire; SIgArate: SIgA secretion rate; URTI: upper respiratory tract infection;

WURSS-21: Wisconsin Upper Respiratory Symptom Survey.



Multiple stressors are likely to induce changes in

mucosal immunity. For example, psychological stress

source is thought to infl uence mucosal immune func-

tion (Jemmott et al., 1983). This possible link between

stress markers and mucosal immunity are reinforced

in the present study, by the fact that the initial levels

of SIgArate were negatively and signifi cantly corre-

lated with the signs and symptoms of stress at the

fourth week, what could indicate that the athletes with

low initial levels of SIgArate (low protection against

pathogens) are more susceptible to be affected by dif-

ferent stressors. In addition, the positive relationship

between symptoms of stress at week four and cortisol

concentrations from both before and after moments,

suggests that a link might exist between these markers.

Further studies taken account the investigated markers

used in the present study, with a longitudinal approach

during the competition season should be considered.

In summary, the present study showed an interesting

congruence between DALDA, WURSS-21 and session-

RPE responses revealing the usefulness of these instru-

ments in a practical setting. The positive relationship

between salivary cortisol levels and sources and symp-

toms of stress showed an agreement between stress mea-

sured by this psychometric instrument and the stress

hormone response. The necessity of monitoring banal

illness that could be associated to stress tolerance and

might impair performance was successfully approached

by the WURSS-21 questionnaire. Moreover, the fi nd-

ings suggest that the athletes with low initial levels of

SIgArate are more susceptible to be affected by different

stressors. A systematic approach incorporating in con-

junction some features linked to training load, per-

ceived stress and indicators of upper respiratory tract

illness could be an effi cient means of monitoring both

stress and recovery in a holistic way and within the

perspective of a biopsychosocial stress model.

Acknowledgments

We would like to thank the FAPESP—São Paulo

Research Foundation (process, 2008/10404-3) for

funding this research. We also wish to acknowledge all

basketball players and research support staff (particu-

larly, Murilo Drago and Gustavo Drago) involved in

this study for their committed participation.

REFERENCES

Barrett, B., Brown, R., Mundt, M., Safdar, N., Dye, L.,

Maberry, R., & Alt, J. (2005). The Wisconsin Upper

Respiratory Symptom Survey is responsive, reliable,

and valid. Journal of Clinical Epidemiology, 58,

609–617.

Bishop, N.C., & Gleeson, M. (2009). Acute and chronic

effects of exercise on markers of mucosal immunity.

Frontiers in Bioscience, 14, 4444–4456.

Budgett, R. (1990). Overtraining syndrome. British

Journal of Sports Medicine, 24(4), 231–236.

Fleshner, M. (2000). Exercise and neuroendocrine regu-

lation of antibody production: Protective effect of

physical activity on stress-induced suppression of the

specifi c antibody response. International Journal of

Sports Medicine, 21(Suppl. 1), S14–S119.

Foster, C. (1998). Monitoring training in athletes

with reference to overtraining syndrome. Medicine

and Science in Sports and Exercise, 30(7), 1164–

1168.

Fry, R.W., Morton, A.R., & Keast, D. (1991). Overtrain-

ing in athletes. An update. Sports Medicine, 12(1),

32–65.

Gozansky, W.S., Lynn, J.S., Laudenslager, M.L., &

Kohrt, W.M. (2005). Salivary cortisol determined by

enzyme immunoassay is preferable to serum total

cortisol for assessment of dynamic hypothalamic–

pituitary–adrenal axis activity. Clinical Endocrinology

(Oxf), 63(3), 336–341.

Hooper, S.L., & Mackinnon, L.T. (1995). Monitoring

overtraining in athletes. Recommendations. Sports

Medicine, 20(5), 321–327.

Jemmott, J.B., 3rd, Borysenko, J.Z., Borysenko, M.,

McClelland, D.C., Chapman, R., Meyer, D., et al.

(1983). Academic stress, power motivation, and

decrease in secretion rate of salivary secretory immu-

noglobulin A. Lancet, 1(8339), 1400–1402.

Kentta, G., & Hassmen, P. (1998). Overtraining and

recovery. A conceptual model. Sports Medicine, 26(1),

1–16.

Lac, G., Lac, N., & Robert, A. (1993). Steroid assays in

saliva: A method to detect plasmatic contaminations.

Archives Internationales de Physiologie, de Biochimie et

de Biophysique, 101(5), 257–262.

Lehmann, M., Foster, C., & Keul, J. (1993). Overtrain-

ing in endurance athletes: A brief review. Medicine

and Science in Sports and Exercise, 25(7), 854–862.

Main, L., & Grove, R. (2009). A multi-component

assessment model for monitoring training distress

among athletes. European Journal of Sport Science, 9,

195–202.

Martin, S.A., Pence, B.D., & Woods, J.A. (2009). Exer-

cise and respiratory tract viral infections. Exercise and

Sport Sciences Reviews, 37(4), 157–164.

Moreira, A., Arsati, F., Cury, P.R., Franciscon, C., de

Oliveira, P.R., & de Araújo, V.C. (2009). Salivary

immunoglobulin a response to a match in top-level

Brazilian soccer players. Journal of Strength and Con-

ditioning Research, 23(7), 1968–1973.

Moreira, A., Arsati, F., Cury, P.R., Franciscon, C., Simoes,

A.C., de Oliveira, P.R., & de Araújo, V.C. (2008). The

impact of a 17-day training period for an interna-

tional championship on mucosal immune parameters

in top-level basketball players and staff members.

European Journal of Oral Sciences, 116(5), 431–437.

Moreira, A., Arsati, F., de Oliveira Lima Arsati, Y.B., da

Silva, D.A., & de Araújo, V.C. (2009). Salivary cortisol

in top-level professional soccer players. European

Journal of Applied Physiology, 106(1), 25–30.

Nederhof, E., Lemmink, K.A., Visscher, C., Meeusen, R.,

& Mulder, T. (2006). Psychomotor speed: Possibly a

new marker for overtraining syndrome. Sports Medi-

cine, 36(10), 817–828.

Neville, V., Gleeson, M., & Folland, J.P. (2008). Salivary

IgA as a risk factor for upper respiratory infections in

elite professional athletes. Medicine and Science in

Sports and Exercise, 40(7), 1228–1236.



Passelergue, P., & Lac, G. (1999). Saliva cortisol, testos-

terone and T/C ratio variations during a wrestling

competition and during the post-competitive recov-

ery period. International Journal of Sports Medicine,

20(2), 109–113.

Quan, N., & Banks, W.A. (2007). Brain-immune com-

munication pathways. Brain, Behavior, and Immu-

nity, 21(6), 727–735.

Robson-Ansley, P.J., Blannin, A., & Gleeson, M. (2007).

Elevated plasma interleukin-6 levels in trained male

triathletes following an acute period of intense inter-

val training. European Journal of Applied Physiology,

99(4), 353–360.

Robson-Ansley, P.J., Gleeson, M., & Ansley, L. (2009).

Fatigue management in the preparation of Olympic

athletes. Journal of Sports Sciences, 27(13), 1409–1420.

Rushall, B.R. (1990). A tool for measuring stress toler-

ance in elite athletes. Journal of Applied Sport Psychol-

ogy, 2, 51–66.

Spence, L., Nissen, M.D., Sloots, T.P., McCormack, J.G.,

Locke, A.S., Pyne, D.B. Brown, W.J. (2005). Upper

respiratory illness aetiology and symptomatology in

elite and recreationally-competitive athletes. Brain,

Behavior, and Immunity, 19, 469–470.

Vining, R.F., McGinley, R.A., Maksvytis, J.J., & Ho, K.Y.

(1983). Salivary cortisol: a better measure of adrenal

cortical function than serum cortisol. Annals of Clini-

cal Biochemistry, 20(Pt. 6), 329–335.

Wira, C.R., Sandoe, C.P., & Steele, M.G. (1990). Gluco-

corticoid regulation of the humoral immune system.

I. In vivo effects of dexamethasone on IgA and IgG in

serum and at mucosal surfaces. Journal of Immunol-

ogy, 144(1), 142–146.

monitoring stress tolerance and occurrences of upper respiratory illness in basketball players by...

Documents