ArticlePDF Available

The stress of chess players as a model to study the effects of psychological stimuli on physiological responses: An example of substrate oxidation and heart rate variability in man

Authors:
  • Rev'Lim Company, France, Limoges

Abstract and Figures

We have studied the physiological consequences of the tension caused by playing chess in 20 male chess players, by following heart rate, heart rate variability, and respiratory variables. We observed significant increase in the heart rate (75-86 beats/min), in the ratio low frequency (LF)/high frequency (HF) of heart rate variability (1.3-3.0) and also a decrease in mean heart rate variability with no changes in HF throughout the game. These results suggest a stimulation of the sympathetic nervous system with no changes in the parasympathetic system. The respiratory exchange ratio was rather elevated (over 0.89) at the start and significantly decreased during the game (0.75 at the end), indicating that energy expenditure progressively switched from carbohydrate to lipid oxidation. The changes in substrate oxidation and the sympathetic system seem to be due to high cognitive demands and bring new insight into adaptations to mental strain.
Content may be subject to copyright.
ORIGINAL ARTICLE
The stress of chess players as a model to study the effects
of psychological stimuli on physiological responses: an example
of substrate oxidation and heart rate variability in man
Nicolas Troubat ÆMarie-Agnes Fargeas-Gluck Æ
Mikko Tulppo ÆBenoit Dugue
´
Accepted: 15 October 2008 / Published online: 6 November 2008
ÓSpringer-Verlag 2008
Abstract We have studied the physiological conse-
quences of the tension caused by playing chess in 20 male
chess players, by following heart rate, heart rate variability,
and respiratory variables. We observed significant increase
in the heart rate (75–86 beats/min), in the ratio low fre-
quency (LF)/high frequency (HF) of heart rate variability
(1.3–3.0) and also a decrease in mean heart rate variability
with no changes in HF throughout the game. These results
suggest a stimulation of the sympathetic nervous system
with no changes in the parasympathetic system. The
respiratory exchange ratio was rather elevated (over 0.89)
at the start and significantly decreased during the game
(0.75 at the end), indicating that energy expenditure pro-
gressively switched from carbohydrate to lipid oxidation.
The changes in substrate oxidation and the sympathetic
system seem to be due to high cognitive demands and bring
new insight into adaptations to mental strain.
Keywords Chess Heart rate variability
Indirect calorimetry Psychological crossover concept
Psychological stress Substrate oxidation
Introduction
Traditionally, the effects of psychological stress in man
have been investigated using two different kinds of situa-
tions: laboratory experiments and real-life stressors.
Laboratory tests (e.g. speech tasks, arithmetic tasks, Stroop
test, etc.) consist of a stimulus of short duration and of
limited potency. Investigations using real-life stressors can
be divided into those using chronic stressors (e.g.
bereavement, unemployment, divorce, caring for patients
with Alzheimer’s disease, etc.) and acute stressors (e.g.
academic exams). One advantage of using arranged stress
situations (laboratory tests and real-life stressors) is that
one can easily use each individual as his or her own con-
trol. However, because of ethical and legal considerations,
it is difficult to experimentally induce pure psychological
stress. Also, it is difficult to avoid unnatural and artificial
arrangements (Dugue
´et al. 1992,2001).
Stress is often defined as a threat (real or implied) to
homeostasis (McEwen and Wingfield 2003) and is known
to stimulate the autonomic nervous system, which in turn
stimulates the cardiovascular system and the metabolism.
Mental effort induces the mobilization of energy for cog-
nitive purposes and induces a compensatory strategy to
protect performance in the presence of augmented request
tasks and psychological stressors (Gaillard 1993,2001).
Though it is well known that glucose is used as a primary
fuel for energy generation in the brain during psychological
stress or mental effort (Rao et al. 2006; Fairclough and
Houston 2004; Sourkes 2006), very little information is
available concerning the global metabolism of substrates
during mental strain. This lack of exploration may be the
result of drawbacks to the available techniques that disturb
the subject during investigation, of difficulties in applying
these techniques, and of continuously monitoring subjects
N. Troubat M.-A. Fargeas-Gluck B. Dugue
´(&)
UFR Sciences du Sport de l’Universite
´de Poitiers et Laboratoire
des Adaptations, Physiologiques aux Activite
´s Physiques
(EA 3813), 4 alle
´e Jean Monnet, 86000 Poitiers, France
e-mail: benoit.dugue@univ-poitiers.fr
M.-A. Fargeas-Gluck
Department of Sport Sciences,
University of Limoges, Limoges, France
M. Tulppo
Department of Physical Rehabilitation, Verve, Oulu, Finland
123
Eur J Appl Physiol (2009) 105:343–349
DOI 10.1007/s00421-008-0908-2
through a mental challenge. However, with the develop-
ment of new generation of portable metabolic systems, it is
now possible to monitor cardio-respiratory variables during
a challenging situation with only minor disturbances.
A chess game represents a legitimate psychological
stress. It is a strategic and high cognitive demand task.
Players have to think through a wide range of move
sequences to find the best choice. This very challenging
and interesting situation has not been thoroughly explored,
and to date, most of the reports have concentrated on
psychological measurements and not on physiological
outcomes. The only available study in that field was the
one of Schwarz et al. (2003).
Accordingly, we studied the effect of the tension caused
by playing a chess game on heart rate, heart rate variability,
and respiratory variables. Using indirect calorimetry, we
deduced the oxidation rate of lipids and carbohydrates and
also total energy expenditure during the challenge. More-
over, we investigated the influences of the expertise of the
players on the physiological responses in this atypical
sport.
Subjects and methods
Subjects
A total of 20 male chess competitors of national and
international level (age: 42 ±13 years; height: 178 ±
4 cm; weight: 76 ±9 kg; BMI: 24 ±3kgm
-2
) partici-
pated in our study. They were subjectively healthy, and
none were on medication. The experiment was conducted
in accordance with the Declaration of Helsinki, and all the
procedures were carried out with written informed consent
of the participants. Volunteers were classified according
their ELO score (official rating of the International Chess
Association). The group of our subjects had an ELO (mean
and extreme values) of 1,757 (1,250–2,170).
Study design
The experiment started with the lunch (standardized) of the
participants, which was taken between 12.00 and 13.00.
Then at 16.30, the participants started their chess session.
Before the start of the experiment, instructions were given
to the participants about the procedures and protocol
requirements during the test. In order to make the partici-
pants comfortable, they were asked to relax in a supine
position for 15 min. Moreover, all participants underwent a
familiarization period with the equipment required for
testing. The experimental room was calm (no more than 2
observers and the player) and light and temperature (18°C)
were continuously regulated.
Chess game
The participants played a chess game against a computer
with software that mimed a level of expertise which was
similar to the player’s level (Chessmaster 9th edition,
2004). This software was used because of the ability to
select a wide range of ELO levels. In fact, without telling
the participants, we set the program at a slightly higher
level (?100 ELO points) than the level of the player. A
laboratory assistant who was familiar with chess was
always present during experiments. He performed the
moves indicated by the computer on the chess board, and
he also served as the human presence in front of the par-
ticipants. One hour was allotted for each player (an
electronic clock was used to control the time). Cardio-
respiratory variables were continuously recorded until the
chess game were over (approximately 90 min, the com-
puter also needed some time before indicating its move).
Psychological measurements
PANAS
This test presents 20 adjectives, 10 that assess positive
affectivity (e.g., excited) and 10 that assess negative
affectivity (e.g., upset) (Watson et al. 1988). These adjec-
tives describe different feelings and emotions. Participants
described their present feelings on a five point scale,
ranging from ‘‘very slightly’’ (1) to ‘‘extremely’’ (5).
Brief COPE (dispositional version of trait anxiety)
This test is the abridged version of the COPE inventory
(Carver et al. 1989) and presents 14 scales that assess dif-
ferent coping dimensions: active coping, planning, using
instrumental support, using emotional support, venting,
behavioral disengagement, self-distraction, self-blame,
positive reframing, humor, denial, acceptance, religion, and
substance use. Each seven point scale, ranging from ‘‘never’
(1) to ‘‘always’’ (7), contains two items (28 items altogether).
Both questionnaires were presented before the start of
the experiment.
Physiological measurements
A portable metabolic measurement system (Vmax ST;
Sensor Medics, Germany) and a heart rate monitor (Polar
S810, Finland) were used to measure the cardio-respiratory
responses and heart rate variability. The gas analyzer sys-
tem was calibrated before each subject session using gases
of known concentrations and used thereafter as previously
described (Brehm et al. 2004; Laurent et al. 2008). The
following variables were recorded throughout the game:
344 Eur J Appl Physiol (2009) 105:343–349
123
heart rate (HR), ventilatory flow (VF), tidal volume (Vt),
breath frequency (bF), O
2
consumption ð_
VO2Þ;CO
2
pro-
duction ð_
VCO2Þ;respiratory exchange ratio (RER), and the
following indices were analyzed after the test: mean R–R,
low frequency (LF), high frequency (HF)—an index of the
activity of the parasympathetic branch of the autonomic
nervous system, LF/HF ratio (LF/HF)—an index of the
activity of the sympathetic branch of the autonomic ner-
vous system, carbohydrate oxidation rate (CHO), lipid
oxidation rate (FAT), and energy expenditure (EE). The
baseline measurements were carried out before the begin-
ning of the match in sitting posture during 3 min.
Data processing
The R–R intervals were recorded (Polar S810, Finland) at a
frequency of 1,000 Hz (Ruha et al. 1997) and saved in a
computer for further analysis of HR variability from the R–
R interval tachogram with Heart Signal software (Kempele,
Finland). All the R–R intervals were edited by visual
inspection, to exclude all the undesirable beats, which
accounted for \1% in every subject. The details of this
analysis and the filtering technique have been described
previously (Huikuri et al. 1992,1996). The mean R–R and
the standard deviation of all R–R intervals were used as
time domain analysis methods. An autoregressive model
(model order 20) was used to estimate the power spectrum
densities of heart rate variability. The power spectra were
quantified by measuring the area under the whole fre-
quency band (total power) and under two frequency bands:
LF power, from 0.04 to 0.15 Hz; and high-frequency
power (HF), from 0.15 to 0.4 Hz. We also calculated LF
and HF in normalized units (n.u) with the same algorithm.
Series of 300 s or approximately 256 consecutive R–R
intervals (which is a minimal time requirement) were
extracted 5 min before the game, at the beginning, at the
middle, and at the end of each game. The same periods were
analyzed for respiratory measurements. Indirect calorimetry
was used to calculate the carbohydrate (CHO) and lipid
oxidation (FAT), and total energy expenditure during the
match. We used stoichiometric equations and appropriate
caloric equivalents (Peronnet and Massicotte 1991), with the
assumption that the nitrogen excretion rate was 135 lg
kg
-1
min
-1
(Romijn et al. 1993). The equations were:
CHO rate oxidation (g min1Þ
¼ð4:585 _
VCO2Þð3:226 _
VO2Þ
Fat rate oxidation (g min1Þ¼ð1:695 _
VO2Þ
ð1:701 _
VCO2Þ:
Mass was expressed in grams per minute and gas
volume in liters per minute. _
VO2and _
VCO2values were
averaged every minute.
Total energy expenditure ¼½ð%CHO=100Þ _
VO2
5:05 kcal L1
þ½ð%Fat=100Þ _
VO2
4:7 kcal L1
The percentages of carbohydrates and lipid oxidations
were calculated by using the following equations:
%CHO ¼½ðRER 0:71Þ=0:29100
%Fat ¼½ð1RERÞ=0:29100:
Statistics
All the statistical analyses were completed using Statistica
5.5 software. Results are presented as their mean ±SD or
extreme values. ANOVA for repeated measurements and
Tukey post hoc tests were used to analyze the data.
Spearman correlation test was also used. Significance was
set at P\0.05.
Results
The PANAS gave a positive affect of 3.2 (2.3–4.3) and a
negative affect of 1.3 (1–1.8). The brief COPE showed an
active coping score of 3 (1–4), planning of 2.9 (1–4),
positive reframing of 2.8 (1.5–3.5), acceptance of 2.7
(1–4), self-distraction of 2.6 (1–4), using instrumental
support of 2.4 (1–4), middle level of humor of 2.2 (1–4),
using emotional support of 2.2 (1–4), self-blame of 2.1
(1.5–3), venting of 2 (1–3), low level of behavioral
disengagement of 1.3 (1–2.5), denial of 1.3 (1–3.5),
substance use of 1.3 (1–3), and religion of 1.2 (1–2).
We observed a significant increase in heart rate right at
the beginning of the contest and the rate stayed elevated
until the end of the game (Fig. 1). Significant increases
both in LF and in the LF/HF ratio (Fig. 1) and a significant
decrease in the mean R–R were also observed (Table 1).
No changes in HF and HF n.u. were found. The CO
2
release and the respiratory exchange ratio significantly
decreased during the game (Fig. 2). When calculating the
oxidation rate, lipid oxidation was found to significantly
increase, whereas glucose oxidation significantly decreased
(Fig. 2). At the 25 min time point, the two oxidation curves
crossed each other. No significant changes were noted in
_
VO2;EE, VF, Vt, and bF.
In addition, no significant correlation was found
between the outcome of the PANAS and brief COPE tests
and any of the physiological variables. All participants lost
their game and reported that their level of effort was sim-
ilar to a tiring, serious match. All of the data concerning
physiological variables before and during chess play are
presented in Table 1. The overall energy expenditure in our
Eur J Appl Physiol (2009) 105:343–349 345
123
players during the entire game was of 138 kcal (extreme
values 102–198 kcal).
Discussion
We have studied the effects of playing chess in chess
competitors (national and international level) on a series of
cardio-respiratory and metabolic variables.
The evaluation of our subjects through the PANAS and
the Brief COPE tests before the chess contest showed that
their basal amount of perceived stress was rather low and
they were psychologically healthy. Also, all of our subjects
reported that the contest was as challenging and tiring as a
regular match. Therefore, artifacts due to specific psycho-
logical state or trait do not seem to generate bias in the
stress-induced physiological responses of our subjects.
Before the beginning of the contest, the heart rate was
rather elevated. Such observations indicate that our par-
ticipants were reacting to the start of the game via
anticipatory mechanisms (Wirtz et al. 2006). At the start of
the game, both heart rate and RER slightly increased. Such
elevated levels could indicate that substrate oxidation
mainly involved carbohydrates. However, the transient
increase in RER may also reflect changes in respiratory
phenomena. Only a slight increase (not significant) in the
ventilation rate was observed at the beginning of the game.
In any case, this indicates that the players were very
reactive. Such changes are certainly under sympathetic
control, and may be related to unspecific stress responses
(Selye 1951). Many studies in humans have documented an
increase in SNS activation during mental stress (e.g. See-
matter et al. 2000; Garde et al. 2002). In fact, the heart rate
variability measurements in our participants at the begin-
ning of the game revealed a significant increase both in LF
and in the LF/HF ratio, a decrease in mean R–R and no
changes in HF, indicating an activation of the sympathetic
system (Montano et al. 1994; Pagani et al. 1991) with no
changes in the parasympathetic system (Hayano et al.
1991). It is well known that Vt and bF have a large impact
on the HRV indices, especially in the vagally mediated HF
spectral band (Hirsch and Bishop 1981). Both Vt and bF
were measured continuously during the study, and we did
not observe any significant changes in breathing pattern.
These results indicate that the changes in the spectral
component of the R–R intervals are due to increased
sympathetic stimulation rather than to changes in respira-
tion pattern or in vagal activation. During the game, we
initially observed stabilization in the heart rate, followed
by a significant increase through the end of the game.
During that time, the CO
2
release significantly decreased,
whereas oxygen consumption stayed stable. This led to a
significant decrease in the RER. One possible explanation
could again be hyperventilation, which could eventually
lead to a relative lowering in CO
2
production (hypocapnia)
related to O
2
consumption. However, no hyperventilation
Fig. 1 Indexes of sympathetic involvement before and during a chess
game: aHeart rate; bLF/HF ratio (number of subject =20);
*P\0.05. LF/HF Ratio between the low and high frequency band
Fig. 2 Indexes of substrate utilization before and during a chess
game: aRER; bCHO and FAT oxidation rate (%) (number of
subject =20); * P\0.05. RER Respiratory exchange ratio; CHO
carbohydrate oxidation rate; FAT lipid oxidation rate
346 Eur J Appl Physiol (2009) 105:343–349
123
was noticed during the course of our study. Therefore, a
significant increase in lipid oxidation and a dramatic
decrease in carbohydrate metabolism may have occurred
during the match.
At the end of the game, the oxidation of carbohydrates
was very low, and the participants were almost exclusively
oxidizing lipids. During the whole game, the total energy
expenditure remained constant, but was more elevated than
during resting time (Levine et al. 2000; Levine 2005).
However, we cannot exclude that we might have observed
a transient increase in carbohydrate consumption at the
beginning of the game and then a return to resting condi-
tion. During the game, the levels of LF and the LF/HF ratio
were elevated and were significantly higher than before the
start of the game. The HF level did not change during the
game. Therefore, the sympathetic system seems to be
stimulated during the course of the contest, with no chan-
ges in the parasympathetic system. However, it has
previously been demonstrated that brief exposure to psy-
chological stressors may lead to both an increase in LF and
in the LF/HF ratio with a reduction of the HF level,
indicating increased sympathetic activity along with with-
drawal of the parasympathetic system (e.g. Delaney and
Brodie 2000). Somehow, our results with respect to the
absence of any parasympathetic withdrawal during the
course of the game are at variance with those reported in
the literature. However, the nature of the stimulus was
different, and the mental workload might have been lower
in our study as our volunteers were well trained in handling
such stimuli. Furthermore, the interplay between the sym-
pathetic and vagal regulation of HR is not always
organized in a reciprocal fashion, wherein increased
activity in one system is accompanied by decreased activity
in the other. A simultaneous sympathetic and vagal acti-
vation has been observed during cold face immersion
(Tulppo et al. 2005), and also in other circumstances in
healthy subjects (Mourot et al. 2007). It is highly possible
that increased sympathetic activation occurs without any
change in vagal outflow during a demanding mental stress
situation without exercise or body position changes, as in
the present study.
All of our observations indicated that the chess players
were very stimulated during the game, but the nature of the
stimuli might have been different during the contest com-
pared to the stimuli that occurred before and at the
beginning of the game. Interestingly, the two oxidation
curves (lipid and carbohydrate) crossed each other 25 min
after the start of the contest. Such changes observed during
the game may reflect an adjusted response to the real
demands of the task. After the more acute response that
was observed right at the beginning of the game, the sub-
ject may have been adjusting to a longer lasting effort.
It is not clear why there could be a switch in substrate
oxidation during a lasting mental challenge. Numerous
studies have shown that different kinds of stressors
(examination, environmental stressors, and laboratory-
Table 1 Heart rate, gas and metabolic variations during the chess match in experienced chess players (n=20)
Parameters Units Before Beginning Middle End
HR beats min
-1
75 (60–101) 81 (59–108)* 79 (65–95) 86 (65–120)*
Mean R–R ms 877 (585–1,210) 819 (666–1,022)* 779 (639–930)* 766 (556–953)*
LF ln ms
2
6.3 (4.2–8.0) 6.7 (5.2–8.1)* 6.8 (4.9–8.2)* 6.6 (4.0–8.2)*
HF ln ms
2
5.7 (3.8–7.3) 6.1 (3.6–7.3) 5.8 (3.6–7.6) 5.7 (2.1–7.4)
HF n.u 33.5 (22–44.6) 32.3 (18.9–51.5) 30.8 (13.6–44.3) 31.4 (13.1–50.2)
LF/HF 1.3 (0.2–5.1) 2.4 (0.5–5.1)* 3.3 (0.8–8.1)* 3.0 (1.0–7.0)*
Vt ml min
-1
0.59 (0.40–0.79) 0.63 (0.44–0.82) 0.55 (0.38–0.80) 0.58 (0.43–0.80)
bF cycle min
-1
15.99 (10.97–20.40) 15.94 (10.86–22.20) 15.94 (10.50–21.40) 16.29 (10.70–22.30)
VF l min
-1
9.61 (6.87–13.38) 10.32 (6.62–13.55) 9.06 (5.95–13.15) 9.52 (5.59–13.30)
_
VO2ml min kg
-1
4.18 (2.36–6.71) 4.51 (2.59–5.80) 4.32 (2.78–5.89) 4.41 (2.59–6.34)
_
VCO2ml min kg
-1
3.57 (2.37–5.45) 3.94 (2.23–5.27) 3.04 (1.95–4.37)* 3.11 (1.72–4.65)*
RER 0.89 (0.79–1.03) 0.92 (0.81–1.07) 0.75 (0.67–0.81)* 0.74 (0.65–0.89)*
CHO g min
-1
0.22 (0.10–0.51) 0.27 (0.11–0.74) 0.01 (0.00–0.16)* 0.002 (0.00–0.32) *
FAT g min
-1
0.08 (0.04–0.21) 0.07 (0.02–0.15) 0.16 (0.09–0.22)* 0.16 (0.07–0.24) *
EE kcal min
-1
1.53 (1.14–2.00) 1.67 (1.18–2.20) 1.53 (1.17–2.01) 1.55 (1.14–2.04)
Results are expressed as mean and extreme values in brackets
HR Heart rate; Mean R–R mean values of heart rate variability; LF low frequency; HF high frequency; LF/HF ratio between the low and high
frequency band; _
VO2O
2
consumption; _
VCO2CO
2
production; RER respiratory exchange ratio; bF respiratory frequency; VF ventilatory flow; Vt
tidal volume; CHO carbohydrate oxidation rate; FAT lipid oxidation rate; EE energy expenditure
*P\0.05 compared to the data obtained before the contest
Eur J Appl Physiol (2009) 105:343–349 347
123
based stressors) may influence metabolism and the con-
centration of lipids in blood (Stoney et al. 1997,1999;
Niaura et al. 1992). However, not much is known con-
cerning the use of substrates during mental challenge.
Interestingly, similar kinds of adaptations have been
reported in exercise physiology. Moderate physical exer-
cise is generally associated with the preponderant
utilization of lipids, whereas acute and intensive physical
exercises are under carbohydrate metabolism. The shift in
substrate oxidation has been described as the ‘‘crossover
concept’’ and depends on the relative intensity of the
exercise and therefore on the endurance training of the
subjects (Brooks and Mercier 1994). Similarly, this may
apply to psychological stress physiology. However, to
validate such a psychological crossover concept, one
should be able to quantify the intensity of psychological
stress and relate it to substrate oxidation. Another inter-
esting feature in this context is that training (endurance
training?) of the subject could influence substrate oxidation
during a mental challenge. One could therefore speculate
that specific training could be designed for chess players.
However, to validate such a new approach, further inves-
tigations are required.
In summary, we herein described an interesting real-life
stressor that seems to be a useful stress model in that it
had significant effects on heart rate variability and
metabolism.
Acknowledgments The study was partly supported by the Chess
League of Limousin, France. The authors are very grateful for the
volunteers who were all very excited to participate and the League of
Limousin that encouraged this research. The Conseil Ge
´ne
´ral de la
Vienne is also thanked for inspiring our collaboration with research
laboratories of the Oulu region (Finland) and for giving a traveling
grant (BD).
References
Brooks GA, Mercier J (1994) Balance of carbohydrate and lipid
utilization during exercise: the ‘‘crossover’’ concept. J Appl
Physiol 76:2253–2261
Brehm MA, Harlaar J, Groepenhof H (2004) Validation of the
portable VmaxST system for oxygen-uptake measurement. Gait
Posture 20:67–73. doi:10.1016/S0966-6362(03)00097-3
Carver CS, Scheier MF, Weintraub JK (1989) Assessing coping
strategies: a theoretically based approach. J Pers Soc Psychol
56:267–283. doi:10.1037/0022-3514.56.2.267
Delaney JP, Brodie DA (2000) Effects of short-term psychological
stress on the time and frequency domains of heart-rate variability.
Percept Mot Skills 91:515–524. doi:10.2466/PMS.91.6.515-524
Dugue
´B, Leppa
¨nen E, Zhou HP, Gra
¨sbeck R (1992) Preanalytical
factors and standardised specimen collection: influence of
psychological stress. Scand J Clin Lab Invest 52:43–50. doi:
10.3109/00365519209085439
Dugue
´B, Leppa
¨nen E, Gra
¨sbeck R (2001) The driving license
examination as a stress model. Effects on blood picture, serum
cortisol and the production of interleukins in man. Life Sci
68:1641–1647. doi:10.1016/S0024-3205(01)00963-8
Fairclough SH, Houston K (2004) A metabolic measure of mental
effort. Biol Psychol 66:177–190. doi:10.1016/j.biopsycho.2003.
10.001
Gaillard AW (1993) Comparing the concepts of mental load and
stress. Ergonomics 36:991–1006. doi:10.1080/001401393089
67972
Gaillard AW (2001) Stress, workload, and fatigue as three biobeha-
vioural states: a general overview. In: Hancock PA, Desmond
PA (eds) Stress, workload, and fatigue. Erlbaum, Mahweh, NJ,
pp 623–639
Garde AH, Laursen B, Jorgensen AH, Jensen BR (2002) Effects of
mental and physical demands on heart rate variability during
computer work. Eur J Appl Physiol 87:456–461. doi:
10.1007/s00421-002-0656-7
Hayano J, Sakakibara Y, Yamada A, Yamada M, Mukai S, Fujinami
T, Yokoyama K, Watanabe Y, Takata K (1991) Accuracy of
assessment of cardiac vagal tone by heart rate variability in
normal subjects. Am J Cardiol 67:199–204. doi:10.1016/0002-
9149(91)90445-Q
Hirsch JA, Bishop B (1981) Respiratory sinus arrhythmia in humans:
how breathing pattern modulates heart rate. Am J Physiol
241:H620–H629
Huikuri HV, Linnaluoto MK, Seppa
¨nen T, Airaksinen KEJ, Kessler
KM, Takkunen JT, Myerburg RJ (1992) Circadian rhythm of
heart rate variability in survivors of cardiac arrest. Am J Cardiol
70:610–615. doi:10.1016/0002-9149(92)90200-I
Huikuri HV, Seppa
¨nen T, Koistinen MJ, Airaksinen KEJ, Ika
¨heimo
MJ, Castellanos A, Myerburg RJ (1996) Abnormalities in beat-
to-beat dynamics of heart rate before the spontaneous onset of
life-threatening ventricular tachyarrhythmias in patients with
prior myocardial infarction. Circulation 93:1836–1844
Laurent CM, Meyers MC, Robinson CA, Strong LR, Chase C,
Goodwin B (2008) Validity of the VmaxST portable metabolic
measurement system. J Sports Sci 26:709–716. doi:10.1080/
02640410701758685
Levine JA, Schleusner SJ, Jensen MD (2000) Energy expenditure of
nonexercise activity. Am J Clin Nutr 72:1451–1454
Levine JA (2005) Measurement of energy expenditure. Public Health
Nutr 8:1123–1132. doi:10.1079/PHN2005800
McEwen BS, Wingfield JC (2003) The concept of allostasis in
biology and biomedicine. Horm Behav 43:2–15. doi:10.1016/
S0018-506X(02)00024-7
Montano N, Ruscone TG, Porta A, Lombardi F, Pagani M, Malliani A
(1994) Power spectrum analysis of heart rate variability to assess
the changes in sympathovagal balance during graded orthostatic
tilt. Circulation 90:1826–1831
Mourot L, Bouhaddi M, Gandelin E, Cappelle S, Nguyen NU, Wolf
JP, Rouillon JD, Hughson R, Regnard J (2007) Conditions of
autonomic reciprocal interplay versus autonomic co-activation:
effects on non-linear heart rate dynamics. Auton Neurosci
137:27–36. doi:10.1016/j.autneu.2007.06.284
Niaura R, Stoney CM, Herbert PN (1992) Lipids in psychological
research: the last decade. Biol Psychol 34:1–43. doi:10.1016/
0301-0511(92)90022-M
Pagani M, Rimoldi O, Pizzinelli P, Furlan R, Crivellaro W, Liberati
D, Cerutti S, Malliani A (1991) Assessment of the neural control
of the circulation during psychological stress. J Auton Nerv Syst
35:33–41. doi:10.1016/0165-1838(91)90036-3
Peronnet F, Massicotte D (1991) Table of non protein respiratory
quotient: an update. Can J Sport Sci 16:23–29
Rao J, Oz G, Seaquist ER (2006) Regulation of cerebral glucose
metabolism. Minerva Endocrinol 31:149–158
Romijn JA, Coyle EF, Sidossis LS, Gastaldelli A, Horowitz JF,
Endert E, Wolfe RR (1993) Regulation of endogenous fat and
carbohydrate metabolism in relation to exercise intensity and
duration. Am J Physiol 265:E380–E391
348 Eur J Appl Physiol (2009) 105:343–349
123
Ruha A, Sallinen S, Nissila
¨S (1997) A real-time microprocessor QRS
detector system with a 1 ms timing accuracy for the measure-
ment of ambulatory HRV. IEEE Trans Biomed Eng 44:159–167.
doi:10.1109/10.554762
Schwarz AM, Schachinger H, Adler RH, Goetz SM (2003) Hope-
lessness is associated with decreased heart rate variability during
championship chess games. Psychosom Med 65:658–661. doi:
10.1097/01.PSY.0000075975.90979.2A
Seematter G, Guenat E, Schneiter P, Cayeux C, Jequier E, Tappy L
(2000) Effects of mental stress on insulin-mediated glucose
metabolism and energy expenditure in lean and obese women.
Am J Physiol Endocrinol Metab 279:E799–E805
Selye H (1951) The general adaptation syndrome and the diseases of
adaptation. Am J Med 10:549–555. doi:10.1016/0002-9343(51)
90327-0
Sourkes TL (2006) On the energy cost of mental effort. J Hist
Neurosci 15:31–47. doi:10.1080/096470490944860
Stoney CM, Niaura R, Bausserman L (1997) Temporal stability of
lipid responses to acute psychological stress in middle-aged men.
Psychophysiology 34:285–291. doi:10.1111/j.1469-8986.1997.
tb02399.x
Stoney CM, Niaura R, Bausserman L, Matacin M (1999) Lipid
reactivity to stress: comparison of chronic and acute stress
responses in middle-aged airline pilots. Health Psychol 18:241–
250. doi:10.1037/0278-6133.18.3.241
Tulppo MP, Kiviniemi AM, Hautala AJ, Kallio M, Seppa
¨nen T,
Ma
¨kikallio TH, Huikuri HV (2005) Physiological background of
the loss of fractal heart rate dynamics. Circulation 112:314–319.
doi:10.1161/CIRCULATIONAHA.104.523712
Watson D, Clark LA, Tellegen A (1988) Development and validation
of brief measures of positive and negative affect: the PANAS
scales. J Pers Soc Psychol 54:1063–1070. doi:10.1037/0022-
3514.54.6.1063
Wirtz PH, Ehlert U, Emini L, Ru
¨disu
¨li K, Groessbauer S, Gaab J,
Elsenbruch S, Von Ka
¨nel R (2006) Anticipatory cognitive stress
appraisal and the acute procoagulant stress response in men.
Psychosom Med 68:851–858. doi:10.1097/01.psy.0000245866.
03456.aa
Eur J Appl Physiol (2009) 105:343–349 349
123
... The discussion about stress in chess players was studied by Troubat et al., in 2009, who evaluated the effects of psychological stimuli on physiological responses. They studied the effects of playing chess in chess competitors with a series of cardiorespiratory and metabolic variables. ...
... Such elevated levels could indicate that substrate oxidation mainly involved carbohydrates. The authors concluded that high cognitive demands during a chess game resulted in sympathetic activation, with great heart rate variability and increased arterial blood pressure 36 . ...
... Two years later, Morphy was found dead in his bathtub at the age of 47. The autopsy showed that he had died of a stroke [33][34][35][36][37][38] . ...
... Looking at other sports like chess, which are mentally but not physically demanding, studies found an increased sympathetic activation for professional and amateur players (Troubat et al., 2009;Fuentes-García et al., 2019). Competitive, performanceoriented esports shows very similar tendencies: Looking at professional esports players in a tournament situation, there is an increase in HR and trends toward a heightenedQ, which implies a high sympathetic activation (Behnke et al., 2019). ...
... In studies on other cognitively oriented sports such as chess, no increased metabolic response could be observed in the professional and amateur levels. However, studies have found an increased stress response in chess players of different performance levels despite the unchanged metabolic response (Troubat et al., 2009;Fuentes-García et al., 2019). At the moment, there is no literature data in the competitive esports area for comparison, but in the CG sector, the same tendencies can be observed in the metabolic reaction, as shown in this study. ...
Article
Full-text available
Introduction: Esports is practiced by millions of people worldwide every day. On a professional level, esports has been proven to have a high stress potential and is sometimes considered equivalent to traditional sporting activities. While traditional sports have health-promoting effects through muscle activity and increased energy expenditure, amateur esports could represent a purely sedentary activity, which would carry potentially harmful effects when practiced regularly. Therefore, this study aims to investigate the acute effects of esports on the cardiovascular system and energy expenditure in amateur esports players to show whether esports can be considered as physical strain or mental stress or whether amateur esports has to be seen as purely sedentary behavior. Methods: Thirty male subjects participated in a 30-min gaming session, playing the soccer simulation game FIFA 20 or the tactical, first-person multiplayer shooter Counter-Strike: Global Offensive. Respiratory and cardiovascular parameters, as well as energy expenditure, blood glucose, lactate, and cortisol, were determined pre-, during, and post-gaming. Results: There were no significant changes in oxygen uptake, carbon dioxide output, energy expenditure, stroke volume, or lactate levels. Heart rate, blood glucose and cortisol decreased through the intervention until reaching their minimum levels 10 min post-gaming (Cortisol pre : 3.1 ± 2.9 ng/ml, Cortisol post : 2.2 ± 2.3 ng/ml, p < 0.01; HR min0.5 : 82 ± 11 bpm, HR post : 74 ± 13 bpm, p < 0.01). Conclusion: A 30-min esports intervention does not positively affect energy expenditure or metabolism in amateur esports players. Therefore, it cannot provide the same health-promoting effects as traditional sports participation, but could in the long-term rather cause the same potentially health-damaging effects as purely sedentary behavior. However, it does not trigger a negative stress response in the players. Deliberate physical activity and exercise routines adapted to these demands should therefore be part of the daily life of amateur esports players.
... In their study, Wang and Morgan (1992) did not observe any difference in RQ between internal, external imaged exercise, and CTRL session. Troubat et al. (2009) investigated the influence of a psychologically stressful situation (i.e., chess game) on substrate oxidation (Troubat et al., 2009). They observed an increase in RQ at the onset of the game and then a decrease during the game. ...
... In their study, Wang and Morgan (1992) did not observe any difference in RQ between internal, external imaged exercise, and CTRL session. Troubat et al. (2009) investigated the influence of a psychologically stressful situation (i.e., chess game) on substrate oxidation (Troubat et al., 2009). They observed an increase in RQ at the onset of the game and then a decrease during the game. ...
Article
Full-text available
Motor imagery (MI) for health and performance strategies has gained interest in recent decades. Nevertheless, there are still no studies that have comprehensively investigated the physiological responses during MI, and no one questions the influence of low-level contraction on these responses. Thus, the aim of the present study was to investigate the neuromuscular, autonomic nervous system (ANS), and cardiometabolic changes associated with an acute bout of MI practice in sitting and standing condition. Twelve young healthy males (26.3 ± 4.4 years) participated in two experimental sessions (control vs. MI) consisting of two postural conditions (sitting vs. standing). ANS, hemodynamic and respiratory parameters, body sway parameters, and electromyography activity were continuously recorded, while neuromuscular parameters were recorded on the right triceps surae muscles before and after performing the postural conditions. While MI showed no effect on ANS, the standing posture increased the indices of sympathetic system activity and decreased those of the parasympathetic system ( p < 0.05). Moreover, MI during standing induced greater spinal excitability compared to sitting posture ( p < 0.05), which was accompanied with greater oxygen consumption, energy expenditure, ventilation, and lower cardiac output ( p < 0.05). Asking individuals to perform MI of an isometric contraction while standing allows them to mentally focus on the motor command, not challenge balance, and produce specific cardiometabolic responses. Therefore, these results provide further evidence of posture and MI-related modulation of spinal excitability with additional autonomic and cardiometabolic responses in healthy young men.
... Chess has been traditionally used as a model in the study of cognitive processes such as memory, decision making or problem solving [1,2] due to the benefits of its practice on mathematical problem-solving ability or logic [3,4]. Previous studies have investigated the mental load and brain activation areas during chess games [5,6] showing that frontal, temporal and parietal areas have predominately activated [7][8][9]. ...
... Previous studies have investigated the mental load and brain activation areas during chess games [5,6] showing that frontal, temporal and parietal areas have predominately activated [7][8][9]. Moreover, previous researches have focused on the study of cognitive load in the autonomic modulation or electroencephalographic (EEG) signal [2,[10][11][12][13]. Furthermore, the expertise paradigm has been explored in chess. ...
Article
The aim of the present study was to analyze the heart rate variability (HRV) and the electroencephalographic (EEG) power spectrum in low and high performance chess players during easy and difficult chess endgames. A total of 28 chess players participated in this cross-sectional study. Participants were divided into two groups according to their ELO level (rating system used by the international chess federation): 1) high level chess players (more than 1600 of ELO score); and 2) low level chess players (ELO less than 1599 of ELO score). Chess players had to complete two easy and two difficult endgames while the electroencephalographic activity and heart rate variability were assessed. High level chess players exhibit more alpha EEG power spectrums (p-value>0.05) during difficult than during easy chess endgames in the occipital area (O1 and O2 electrodes). Moreover, high performance players showed a reduced autonomic modulation (p-value>0.05) during the difficult chess endgames which low performance players did not reach. These results could suggest that high level chess players adapt their neurophysiological response to the task demand.
... Some studies examine the heart rates when subjects are under strain. For instance, Troubat et al. (2009) record changes in heart rate and metabolism among chess players and show heart rate rises during mental stress. ...
... However, we found no difference in cognitive energy expenditure (CEE), nor in test response accuracy, between Ε4 carriers and non-carriers ( Fig. 4g and Supplemental Fig. 9). To our knowledge, only two other studies have attempted to utilize IC to quantify the contribution of cerebral activation (i.e. a mental task) to whole body metabolic measures [49,50]. While we did not observe an APOE effect on metabolic measures during the cognitive challenge, we did find that IC is a sensitive tool to evaluate metabolic changes due to mental stress, as all participants showed a significant increase in energy expenditure (Fig. 4f). ...
Article
Full-text available
Background Cerebral glucose hypometabolism is consistently observed in individuals with Alzheimer’s disease (AD), as well as in young cognitively normal carriers of the Ε4 allele of Apolipoprotein E (APOE), the strongest genetic predictor of late-onset AD. While this clinical feature has been described for over two decades, the mechanism underlying these changes in cerebral glucose metabolism remains a critical knowledge gap in the field. Methods Here, we undertook a multi-omic approach by combining single-cell RNA sequencing (scRNAseq) and stable isotope resolved metabolomics (SIRM) to define a metabolic rewiring across astrocytes, brain tissue, mice, and human subjects expressing APOE4. Results Single-cell analysis of brain tissue from mice expressing human APOE revealed E4-associated decreases in genes related to oxidative phosphorylation, particularly in astrocytes. This shift was confirmed on a metabolic level with isotopic tracing of ¹³ C-glucose in E4 mice and astrocytes, which showed decreased pyruvate entry into the TCA cycle and increased lactate synthesis. Metabolic phenotyping of E4 astrocytes showed elevated glycolytic activity, decreased oxygen consumption, blunted oxidative flexibility, and a lower rate of glucose oxidation in the presence of lactate. Together, these cellular findings suggest an E4-associated increase in aerobic glycolysis (i.e. the Warburg effect). To test whether this phenomenon translated to APOE4 humans, we analyzed the plasma metabolome of young and middle-aged human participants with and without the Ε4 allele, and used indirect calorimetry to measure whole body oxygen consumption and energy expenditure. In line with data from E4-expressing female mice, a subgroup analysis revealed that young female E4 carriers showed a striking decrease in energy expenditure compared to non-carriers. This decrease in energy expenditure was primarily driven by a lower rate of oxygen consumption, and was exaggerated following a dietary glucose challenge. Further, the stunted oxygen consumption was accompanied by markedly increased lactate in the plasma of E4 carriers, and a pathway analysis of the plasma metabolome suggested an increase in aerobic glycolysis. Conclusions Together, these results suggest astrocyte, brain and system-level metabolic reprogramming in the presence of APOE4, a ‘Warburg like’ endophenotype that is observable in young females decades prior to clinically manifest AD.
... Higher RLC (N = 72) Mean (SE) g/100 g fat g/100 ml milk g/100 g fat g/100 ml milk g/100 g fat g/100 ml milk www.nature.com/scientificreports/ As a consequence, as demonstrated in a study on metabolic changes during mental stress, there is a shift in the utilization of the substrate, from oxidizing mainly glucose at the beginning to oxidizing mainly lipids at the end of process 44 . Such a shift may result in differential access to the metabolic substrate for milk synthesis, leaving less substrate available for milk carbohydrate synthesis and more substrate for milk fat synthesis. ...
Article
Full-text available
We studied a sample of 146 Polish, exclusively breastfeeding mothers and their healthy born on time infants to explore the effect of perinatal psychosocial stress on breast milk composition. Maternal perinatal stress was assessed using Recent Life Changes Questionnaire summarizing stressful events from the previous six months. Stress reactivity was determined by administering the cold pressor test and measuring cortisol in saliva samples taken during the test. Breast milk sample was taken to measure energy, protein, fat, lactose, and fatty acid content. Analyses revealed that stress reactivity was positively associated with milk fat and long-chain unsaturated fatty acids and negatively associated with milk lactose. Perinatal psychosocial stress negatively affected energy density, fat as well as medium-chain and long-chain saturated fatty acids in milk. These results, together with previous studies, advocate monitoring maternal psychological status during the peripartum to promote breastfeeding and healthy infant nutrition.
Article
Puerperium may lead to memory and executive/attentional complaints that interfere with women’s daily life. This might be prevented by dietary compounds, such as neuroprotective polyphenols. Their bioactivity depends on their effects on lipid metabolism in different tissues, such as the brain, fat, and breast. Thus, a polyphenol-related cognitive improvement may be associated with changes of lipids in human milk, which are key for infant neurodevelopment. A cross-sectional study was conducted on 75 postpartum women from Córdoba (Argentina), involving several neuropsychological tests. Diet was registered to identify polyphenol intake and food pattern adherence, with sociodemographic and other psychological variables (insomnia, stress, subjective cognitive complaints) being also studied. Triacylglycerols, cholesterol, and their oxidative forms were analyzed as milk biomarkers. Multivariate statistical methods were applied. Results confirmed that women who consumed polyphenols presented better executive/attentional performance (i.e., higher correct responses, conceptual level responses, complete categories, verbal fluency; lower attentional interferences, and perseverative errors) and word retention with lower interference. Polyphenols were positively associated with milk lipids, which were higher in women with better cognition. Furthermore, they had lower oxidized triacylglycerols. In conclusion, polyphenolic intake during postpartum may improve executive/attentional functioning, memory, and milk lipid profile.
Article
A growing literature identifies associations between subjective and biometric indicators of wellbeing. These associations, together with the ability of subjective wellbeing metrics to predict health and behavioral outcomes, have spawned increasing interest in wellbeing as an important concept in its own right. However, some social scientists continue to question the usefulness of wellbeing metrics. We contribute to this literature in three ways. First, we introduce a biometric measure of wellbeing – pulse – that hs been little used. Using nationally representative data on 165,000 individuals from the Health Survey for England and Scottish Health Surveys we show that its correlates are similar in a number of ways to those for happiness, and that it is highly correlated with wellbeing metrics, as well as self-assessed health. Second, we examine the determinants of pulse rates in mid-life (age 42) among the 9,000 members of the National Child Development Study, a birth cohort born in a single week in 1958 in Britain. Third, we track the impact of pulse measured in mid-life (age 42) on health and labor market outcomes at age 50 in 2008 and age 55 in 2013. The probability of working at age 55 is negatively impacted by pulse rate a decade earlier. The pulse rate has an impact over and above chronic pain measured at age 42. General health at 55 is lower the higher the pulse rate at age 42, while those with higher pulse rates at 42 also express lower life satisfaction and more pessimism about the future at age 50. Taken together, these results suggest social scientists can learn a great deal by adding pulse rates to the metrics they use when evaluating people’s wellbeing.
Article
Background: A construction method has emerged in which a camera is installed around a construction machine, and the operator remotely controls the machine while synchronizing the vibration of the machine with the images seen from the operator's seat using virtual reality (VR) technology. Indices related to changes in heart rate (HR) and physical vibration, such as heart rate variability (HRV) and multiscale entropy (MSE), can then be measured among the operators. As these indices are quantitative measures of autonomic regulation in the cardiovascular system, they can provide a useful means of assessing operational stress. Objective: In this study, we aimed to evaluate changes in HR and body vibration of machine operators and investigate appropriate methods of machine operation while considering the psychological load. Methods: We enrolled 9 remote operators (18-50 years old) in the experiment, which involved 42 measurements. A construction machine was driven on a test course simulating a construction site, and three patterns of operation-riding operation, remote operation using monitor images, and VR operation combining monitor images and machine vibration-were compared. The heartbeat, body vibration, and driving time of the participants were measured using sensing wear made of a woven film-like conductive material and a three-axis acceleration measurement device (WHS-2). We used HRV analysis in the time and frequency domains, MSE analysis as a measure of the complexity of heart rate changes, and the ISO (International Standards Organization) 2631 vibration index. Multiple regression analysis was conducted to model the relationship among the low frequency (LF)/high frequency (HF) HRV, MSE, vibration index, and driving time of construction equipment. Efficiency in driving time was investigated with a focus on stress reduction. Results: Multiple comparisons conducted via the Bonferroni test and Kruskal-Wallis test showed statistically significant differences (P=.05) in HRV-LF/HF, the vibration index, weighted acceleration, motion sickness dose value (MSDVz), and the driving time among the three operation patterns. The riding operation was found to reduce the driving time of the machine, but the operation stress was the highest in this case; operation based on the monitor image was found to have the lowest operation stress but the longest operation time. Multiple regression analysis showed that the explanatory variables (LH/HF), RR interval, and vibration index (MSDVz by vertical oscillation at 0.5-5 Hz) had a negative effect on the driving time (adjusted coefficient of determination R2=0.449). Conclusions: A new method was developed to calculate the appropriate operating time by considering operational stress and suppressing the physical vibration within an acceptable range. By focusing on the relationship between psychological load and physical vibration, which has not been explored in previous studies, the relationship of these variables with the driving time of construction machines was clarified.
Article
Full-text available
In order to devise and evaluate standardized specimen collection procedures, we studied the influence of psychological stress on the results of commonly analysed blood components: creatine kinase, lactate dehydrogenase, total protein and albumin in serum and blood picture. In addition, serum cortisol was assayed. Two kinds of stress were used: the Stroop test, a colour conflict task, and the thrill caused by the first jump of new parachutists. More changes were observed after the parachutist test than after the Stroop test. There was a difference in the responses of males and females. Females were more sensitive, especially to the parachutist test. Most of the changes observed were interpreted as being caused by haemoconcentration, possibly related to muscular tension. Cortisol, commonly used to indicate the level of stress, did not react much and is therefore not a good index of psychological stress.
Article
Full-text available
The purpose of this paper is to point out some limits and inconsistencies in the table of nonprotein respiratory quotient that is universally used. This table, developed by Lusk in 1924, was derived from biochemical and physical data that are now outdated. A new table of nonprotein respiratory quotient, consistent with modern chemical and physical data, is proposed. The revised table is based on (a) the average composition of human triacylglycerol stores, (b) energy potential of fatty acids and glucose, and (c) the volumes occupied by one mole of oxygen or carbon dioxide (which are not ideal gases) under STPD conditions.
Article
We have studied the following stress model: the tension caused by sitting for the theoretical part of the driving license examination. Volunteers were investigated twice, after their driving license examination and after a (stress-free) control session. The effects of the stress were investigated by studying the blood picture (differential counts), serum concentration of cortisol, and cytokine production in stimulated blood cells. Relationships between the subjective perception of stress and the physiological reaction were also investigated.This stress induced significant increase in the concentrations of cortisol and hemoglobin, and in the values of hematocrit and MCV, and in the lipopolysaccharide-induced release of IL-1beta and -6. The subjective feelings of irritability and wakefulness were also significantly higher after the exam. A significant relationship was found between the changes in the stimulated production of IL-1beta and irritability. The responsiveness to psychological stress might be influenced by the temporary mood of the subjects.
Article
In recent studies of the structure of affect, positive and negative affect have consistently emerged as two dominant and relatively independent dimensions. A number of mood scales have been created to measure these factors; however, many existing measures are inadequate, showing low reliability or poor convergent or discriminant validity. To fill the need for reliable and valid Positive Affect and Negative Affect scales that are also brief and easy to administer, we developed two 10-item mood scales that comprise the Positive and Negative Affect Schedule (PANAS). The scales are shown to be highly internally consistent, largely uncorrelated, and stable at appropriate levels over a 2-month time period. Normative data and factorial and external evidence of convergent and discriminant validity for the scales are also presented. (PsycINFO Database Record (c) 2010 APA, all rights reserved)
Article
In this study, we used spectral analysis of short-term R-R and systolic arterial pressure (SAP) variabilities to estimate the changes in neural control of the circulation produced by psychological stress. The 0.1 Hz low-frequency (LF) component of R-R and SAP variabilities provided a quantitative index of the sympathetic activity controlling heart rate and vasomotion. Conversely the high-frequency (HF) respiratory component of R-R variability provided an index of vagal tone. In conscious dogs we used the seemingly stressful situation of being accompanied for the first time to the experimental laboratory as a stimulus. In human subjects we used mental arithmetic. In both cases LF of R-R and SAP variabilities increased significantly suggesting enhanced sympathetic activity both to the SA node and the vasculature. In man, the index α, a measure of the overall gain of baroreceptor mechanisms, was found to be reduced during mental arithmetic. Spectral analysis of cardiovascular variabilities thus suggests that in man and in conscious dogs psychological challenges induce a profound re-arrangement of neural control of the circulation, which appears to be characterised by sympathetic predominance and which can be monitored by this technique.
Article
We review the recent literature examining lipid changes during stressful experiences, and the psychological and constitutional differences that influence lipid levels at rest and that may modulate lipid response to stress. Mild forms of chronic or episodic stress are apparently not associated with alterations in lipids and lipoproteins, but severe forms of real or perceived stress do appear to alter lipid levels. Acute laboratory stress is frequently associated with short-term alterations in lipids and lipoproteins, but the significance of these changes is unclear. Several individual characteristics, such as heightened neuroendocrine or autonomic reactivity to stressors, Type A component behavior, and other aspects of personality, appear to be associated with an atherogenic lipid profile. Stress may influence lipid concentrations and metabolism through a variety of physiological and behavioral mechanisms, but none have been clearly elucidated. Future research should concentrate on understanding these mechanisms.
Article
Reduced heart rate (HR) variability is associated with increased risk of cardiac arrest in patients with coronary artery disease. In this study, the power spectral components of HR variability and their circadian pattern in 22 survivors of out-of-hospital cardiac arrest not associated with acute myocardial infarction were compared with those of 22 control patients matched with respect to age, sex, previous myocardial infarction, ejection fraction and number of diseased coronary arteries. Survivors of cardiac arrest had significantly lower 24-hour average standard deviation of RR intervals than control patients (29 +/- 10 vs 51 +/- 15 ms, p less than 0.001), and the 24-hour mean high frequency spectral area was also lower in survivors of cardiac arrest than in control patients (13 +/- 7 ms2 x 10 vs 28 +/- 14 ms2 x 10, p less than 0.01). In a single cosinor analysis, a significant circadian rhythm of HR variability was observed in both groups with the acrophase of standard deviation of RR intervals and high-frequency spectral area occurring between 3 and 6 A.M. which was followed by an abrupt decrease in HR variability after arousal. The amplitude of the circadian rhythm of HR variability did not differ between the groups. Thus, HR variability is reduced in survivors of cardiac arrest but its circadian rhythm is maintained so that a very low HR variability is observed in the morning after awakening, corresponding to the time period at which the incidence of sudden cardiac death is highest.
Article
In this study, we used spectral analysis of short-term R-R and systolic arterial pressure (SAP) variabilities to estimate the changes in neural control of the circulation produced by psychological stress. The 0.1 Hz low-frequency (LF) component of R-R and SAP variabilities provided a quantitative index of the sympathetic activity controlling heart rate and vasomotion. Conversely the high-frequency (HF) respiratory component of R-R variability provided an index of vagal tone. In conscious dogs we used the seemingly stressful situation of being accompanied for the first time to the experimental laboratory as a stimulus. In human subjects we used mental arithmetic. In both cases LF of R-R and SAP variabilities increased significantly suggesting enhanced sympathetic activity both to the SA node and the vasculature. In man, the index alpha, a measure of the overall gain of baroreceptor mechanisms, was found to be reduced during mental arithmetic. Spectral analysis of cardiovascular variabilities thus suggests that in man and in conscious dogs psychological challenges induce a profound re-arrangement of neural control of the circulation, which appears to be characterised by sympathetic predominance and which can be monitored by this technique.