In der vorliegenden Untersuchung wurde ein arbeitspsychologisches Problem thematisiert, dass in Mensch-Maschine-Systemen auftritt. <br /> In Mensch-Maschine-Systemen werden Informationen in kodierter Form ausgetauscht. Diese inhaltlich verkürzte Informationsübertragung hat den Vorteil, keine lange Zustandsbeschreibung zu benötigen, so dass der Mensch auf die veränderten Zustände schnell und effizient reagieren kann. Dies wird aber nur dann ermöglicht, wenn der Mensch die kodierten Informationen (Kodes) vorher erlernten Bedeutungen zuordnen kann. Je nach Art der kodierten Informationen (visuelle, akustische oder alphanumerische Signale) wurden Gestaltungsempfehlungen für Kodealphabete entwickelt. <br /> Für Operateure resultiert die mentale Belastung durch Dekodierungsprozesse vor allem aus dem Umfang des Kodealphabetes (Anzahl von Kodezeichen), der wahrnehmungsmäßigen Gestaltung der Kodes und den Regeln über die Zuordnung von Bedeutungen zu Kodezeichen. <br /> <br /> Die Entscheidung über die Güte von Kodealphabeten geschieht in der Arbeitspsychologie in der Regel über Leistungsindikatoren. Dies sind üblicherweise die zur Dekodierung der Kodes benötigte Zeit und dabei auftretende Zuordnungsfehler. Psychophysiologische Daten werden oft nicht herangezogen.<br /> Fraglich ist allerdings, ob Zeiten und Fehler allein verlässliche Indikatoren für den kognitiven Aufwand bei Dekodierungsprozessen sind, da im hochgeübten Zustand bei gleichen Alphabetlängen, aber unterschiedlicher Kodezeichengestaltung sich häufig die mittleren Dekodierungszeiten zwischen Kodealphabeten nicht signifikant unterscheiden und Fehler überhaupt nicht auftreten. <br /> Die in der vorliegenden Arbeit postulierte Notwendigkeit der Ableitung von Biosignalen gründet sich auf die Annahme, dass mit ihrer Hilfe zusätzliche Informationen über die mentale Beanspruchung bei Dekodierungsprozessen gewonnen werden können, die mit der Erhebung von Leistungsdaten nicht erfasst werden. Denn gerade dann, wenn sich die Leistungsdaten zweier Kodealphabete nicht unterscheiden, können psychophysiologische Daten unterschiedliche Aspekte mentaler Beanspruchung erfassen, die mit Hilfe von Leistungsdaten nicht bestimmt werden können. <br /> Daher wird in Erweiterung des etablierten Untersuchungsansatzes vorgeschlagen, Biosignale als dritten Datenbereich, neben Leistungsdaten und subjektiven Daten mentaler Beanspruchung, abzuleiten, um zusätzliche Informationen über die mentale Beanspruchung bei Dekodierungsprozessen zu erhalten.<br /> Diese Annahme sollte mit Hilfe der Ableitung von Biosignalen überprüft werden. <br /> <br /> Der Begriff mentaler Beanspruchung wird in der bisherigen Literatur nur unzureichend definiert und differenziert. Daher wird zur Untersuchung dieses Konzepts, die wissenschaftliche Literatur berücksichtigend, ein erweitertes Modell mentaler Beanspruchung vorgestellt.<br /> Dabei wird die mentale Beanspruchung abgegrenzt von der emotionalen Beanspruchung. Mentale Beanspruchung wird weiterhin unterschieden in psychomotorische, perzeptive und kognitive Beanspruchung. Diese Aspekte mentaler Beanspruchung werden jeweils vom psychomotorischen, perzeptiven oder kognitiven Aufwand der zu bearbeitenden Aufgabe ausgelöst.<br /> <br /> In der vorliegenden Untersuchung wurden zwei zentrale Fragestellungen untersucht:<br /> Einerseits wurde die Analyse der anwendungsbezogenen Frage fokussiert, inwieweit psychophysiologische Indikatoren mentaler Beanspruchung über die Leistungsdaten (Dekodierungszeiten und Fehleranzahl) hinaus, zusätzliche Informationen zur Bestimmung der Güte von Kodealphabeten liefern. <br /> Andererseits wurde der Forschungsaspekt untersucht, inwieweit psychophysiologische Indikatoren mentaler Beanspruchung die zur Dekodierung notwendigen perzeptiven und kognitiven Aspekte mentaler Beanspruchung differenzieren können. Emotionale Beanspruchung war nicht Gegenstand der Analysen, weshalb in der Operationalisierung versucht wurde, sie weitgehend zu vermeiden. Psychomotorische Beanspruchung als dritter Aspekt mentaler Beanspruchung (neben perzeptiver und kognitiver Beanspruchung) wurde für beide Experimentalgruppen weitgehend konstant gehalten.<br /> <br /> In Lernexperimenten hatten zwei anhand eines Lern- und Gedächtnistests homogenisierte Stichproben jeweils die Bedeutung von 54 Kodes eines Kodealphabets zu erwerben. Dabei wurde jeder der zwei unahbhängigen Stichproben ein anderes Kodealphabet vorgelegt, wobei sich die Kodealphabete hinsichtlich Buchstabenanzahl (Kodelänge) und anzuwendender Zuordnungsregeln unterschieden. Damit differierten die Kodealphabete im perzeptiven und kognitiven Aspekt mentaler Beanspruchung.<br /> Die Kombination der Abkürzungen entsprach den in einer Feuerwehrleitzentrale verwendeten (Kurzbeschreibungen von Notfallsituationen). In der Lernphase wurden den Probanden zunächst die Kodealphabete geblockt mit ihren Bedeutungen präsentiert. <br /> Anschließend wurden die Kodes (ohne deren Bedeutung) in sechs aufeinanderfolgenden Prüfphasen randomisiert einzeln dargeboten, wobei die Probanden instruiert waren, die Bedeutung der jeweiligen Kodes in ein Mikrofon zu sprechen. <br /> Während des gesamten Experiments wurden, neben Leistungsdaten (Dekodierungszeiten und Fehleranzahl) und subjektiven Daten über die mentale Beanspruchung im Verlauf der Experimente, folgende zentralnervöse und peripherphysiologische Biosignale abgeleitet: Blutdruck, Herzrate, phasische und tonische elektrodermale Aktivität und Elektroenzephalogramm. Aus ihnen wurden zunächst 13 peripherphysiologische und 7 zentralnervöse Parameter berechnet, von denen 7 peripherphysiologische und 3 zentralnervöse Parameter die statistischen Voraussetzungen (Einschlusskriterien) soweit erfüllten, dass sie in die inferenzstatistische Datenanalyse einbezogen wurden.<br /> <br /> Leistungsdaten und subjektive Beanspruchungseinschätzungen der Versuchsdurchgänge wurden zu den psychophysiologischen Parametern in Beziehung gesetzt. Die Befunde zeigen, dass mittels der psychophysiologischen Daten zusätzliche Erkenntnisse über den kognitiven Aufwand gewonnen werden können.<br /> <br /> Als weitere Analyse wurden die Kodes post hoc in zwei neue Kodealphabete eingeteilt. Ziel dieser Analyse war es, die Unterschiede zwischen beiden Kodealphabeten zu erhöhen, um deutlichere reizbezogene psychophysiologische Unterschiede in den EEG-Daten zwischen den Kodealphabeten zu erhalten. Dazu wurde diejenigen, hinsichtlich ihrer Bedeutung, parallelen Kodes in beiden Kodealphabeten ausgewählt, die sich in der Dekodierungszeit maximal voneinander unterschieden. Eine erneute Analyse der EEG-Daten erbrachte jedoch keine Verbesserung der Ergebnisse.<br /> <br /> Drei Hauptergebnisse bezüglich der psychophysiologischen Parameter konnten festgestellt werden:<br /> Das erste Ergebnis ist für die psychophysiologische Methodik bedeutsam. Viele psychophysiologische Parameter unterschieden zwischen den Prüfphasen und zeigen damit eine hinreichende Sensitivität zur Untersuchung mentaler Beanspruchung bei Dekodierungsprozessen an. Dazu gehören die Anzahl der spontanen Hautleitwertsreaktionen, die Amplitude der Hautleitwertsreaktionen, das Hautleitwertsniveau, die Herzrate, die Herzratendifferenz und das Beta-2-Band des EEG. Diese Parameter zeigen einen ähnlichen Verlauf wie die Leistungsdaten. Dies zeigt, dass es möglich ist, die hier operationaliserte Art mentaler Beanspruchung in Form von Dekodierungsprozessen psychophysiologisch zu analysieren.<br /> <br /> Ein zweites Ergebnis betrifft die Möglichkeit, Unterschiede mentaler Beanspruchung zwischen beiden Gruppen psychophysiologisch abzubilden:<br /> Das Hautleitwertsniveau und das Theta-Frequenzband des Spontan-EEG zeigten Unterschiede zwischen beiden Stichproben von der ersten Prüfphase an. Diese Parameter indizieren unterschiedlichen kognitiven Aufwand in beiden Stichproben über alle Prüfphasen.<br /> <br /> Das wichtigste Ergebnis betrifft die Frage nach einem Informationsgewinn bei Einsatz psychophysiologischer Methoden zur Bewertung der Güte von Kodealphabeten: <br /> Einen tatsächlichen Informationsgewinn gegenüber den Leistungsdaten zeigte die Amplitude der elektrodermalen Aktivität und die Herzraten-Differenz an. Denn in den späteren Prüfphasen, wenn sich die Leistungsdaten beider Kodealphabete nicht mehr unterschieden, konnten unterschiedliche Ausprägungen dieser psychophysiologischen Parameter zwischen beiden Kodealphabeten verzeichnet werden. Damit konnten unterschiedliche Aspekte mentaler Beanspruchung in beiden Kodealphabeten in den späteren Prüfphasen erfasst werden, in denen sich die Leistungsdaten nicht mehr unterschieden. <br /> <br /> Alle drei Ergebnisse zeigen, dass es, trotz erheblichen technischen und methodischen Aufwands, sinnvoll erscheint, bei der Charakterisierung mentaler Belastungen und für die Gestaltung von Kodealphabeten auch psychophysiologische Daten heranzuziehen, da zusätzliche Informationen über den perzeptiven und kognitiven Dekodierungsaufwand gewonnen werden können. / In this study a problem from the work psychology was focussed, which appears in human-machine systems.<br /> In human-machine systems informations were exchanged as codes. Using this kind of shortened information transmission needs no long description of the system state, so that the operator can react to the changed system state in a quick and efficient way. This is possible only in this case, if the operator has learned the meaning of the codes before. For the different kinds of coded informations (visual, acoustic or alphanumeric signals) special recommendations for their design were developed.<br /> Mental workload caused by decoding processes resulting from the size of the code alphabet, the percepted design of the codes, and the rules about the allocation of code meanings.<br /> <br /> The decision about the validity of code alphabets in work psychology is normally made by indicators of performance, which are the decoding times and decoding mistakes. Nearly all studies do not refer to psychophysiological data. <br /> It is questioned, if times and mistakes alone are valid indicators for the cognitive cost, because in well learned state and for the same size of the code alphabet but different design of the codes, the decoding times between code alphabets are not significantly different, and mistakes do not appear.<br /> This study postulates a necessity for the registration of psychophysiological data, so that additionally informations, which are not included in the performance data, can be examined. If the performance data does not differ between two code alphabets, psychophysiological data measures different aspects of mental workload, which could not be detected by performance data. To enlarge the established approach, it is recommended to registrate biosignals as a third domain of data to get additional informations about decoding processes.<br /> These hypotheses should be verified by registration of biosignals.<br /> <br /> There are vague definitions and deficient differentiations of the concept of mental workload in the scientific publications. To examine mental workload an enlarged model of mental workload is presented. Mental workload is delimited from emotional strain. Furthermore mental workload is differentiated in psychomotoric, perceptive, and cognitive aspects. These aspects of mental workload are caused by the psychomotoric, perceptive, and cognitive cost, which are initiated by the assigned task.<br /> <br /> Two main questions were examined in this study. <br /> First question refers to applied research. Do psychophysiological indicators of mental workload provide more information about the validity of code alphabets than performance data?<br /> The second question refers to what extent psychophysiological indicators of mental workload necessary for the decoding process could differentiate the perceptive and cognitive aspects of mental workload. <br /> <br /> >The emotional strain was not the objective of this study, therefore it was excluded from the experimental design.<br /> Psychomotoric workload as the third aspect of mental workload was a constant value for both experimental samples.<br /> <br /> In two learning experiments two samples with identical habituational memory performance were instructed to learn the meaning of 54 codes of a code alphabet. Both samples was presented another code alphabet, which differed in the number of included letters and the allocation rules. Thus the two code alphabets differed in the perceptive and in the cognitive aspect of mental workload.<br /> The combination of abbreviations was comparable to those used in a fire station. In a learning phase the code alphabets were presented with their meanings. Afterwards the codes were presented without their meanings in six following tests phases. Subjects were instructed to answer in a microphone. <br /> During the whole experiment performance data, subjective data of perceived strain, and psychophysiological data were registrated. The psychophysiological data contained: blood pressure, heart rate, phasic and tonic electrodermal activity, and the EEG. Thirteen peripherphysiological and seven EEG parameters were extracted from these raw data. Seven peripherphysiological and three EEG parameters accomplished the statistical premises and were included to further statistical analysis.<br /> Performance data and subjective data were set in relation to the psychophysiological parameters. The outcomes showed that using psychophysiological data generate additional informations about the cognitive cost.<br /> <br /> For further analysis the code items were divided into two new code alphabets. The intention of this analysis was to maximize the difference between the two code alphabets to get more stimuli based psychophysiological differences in the EEG data. This analysis included those pairs of codes with identical meaning and maximum difference in their decoding time. This further analysis did not improve the outcomes. <br /> <br /> Three main outcomes in respect to the psychophysiological data were detected. <br /> The first one is an important outcome for psychophysiological methodology. Many psychophysiological parameters differ between the test phases and thus show a sufficient sensitivity to examine mental workload in decoding processes. The number of spontaneous electrodermal responses, the amplitude of electrodermal responses, the electrodermal level, the heart rate, the heart rate difference, and the beta-2 frequency band of the EEG belong to these parameters. These parameters show a similar distribution like performance data. This shows the possibility of the operationalized mental workload through decoding processes analysable with psychophysiological methods.<br /> A second outcome concerns the possibility to show differences in mental workload between both samples in psychophysiological parameters:<br /> The electrodermal level and the theta frequency band of the EEG showed differences between both samples beginning from the first test phase. These parameters indicate different cognitive cost in both samples in all test phases.<br /> <br /> The most important outcome regards to the profit of information by using psychophysiological methods to test the validity of code alphabets. The amplitude of the electrodermal responses and the heart rate difference shows a surplus of information compared to performance data. Thus in later test phases, in which the performance data did no longer differ, different characteristics of psychophysiological parameters between both code alphabets were registrated. Therefore different aspects of mental workload could be quantified.<br /> <br /> All three outcomes showed that, nevertheless of the considerable technical and methodological expenditure, it is reasonable to use psychophysiological data to design code alphabets, because it supplies additional information about the perceptional and cognitive cost of the decoding processes.

Assessment of heat strain considers an individual's tolerance and indicates the risk and physiological cost of working in hot environments. This study evaluated the discrimination ability of metrics of heat strain. The null hypotheses were that (1) the metrics individually could not discriminate between acceptable and unacceptable heat strain, (2) there were no significant differences among these metrics, and (3) there were no significant differences in the applicability of the metrics due to clothing or heat stress level. The experimental design was a case crossover. Clothing and heat stress level were potential confounders. Two clothing ensembles were work clothes and vapor-barrier coveralls with hood. Two heat stress levels for a moderate metabolic rate were 5°C-WBGT and 10°C-WBGT above the Threshold Limit Value adjusted for clothing. Eight male and four female acclimated individuals (age 18-36 years) participated. Four experimental trials were randomized in sequence. The transition point, when a participant's status changed from control (acceptable heat strain) to case (unacceptable), was the first occurrence of rectal temperature equal to or greater than 38.5°C, heart rate equal to or greater than 90% of maximum, or volitional fatigue. The metrics were rectal, ear canal, oral, and disk temperatures, heart rate including moving time averages of 5, 10, 20, 30 and 45 minutes, recovery heart rate, and physiological strain index. The data at the transition point were the case data; the data 10 minutes prior to that point were the control data. Analyses used primarily receiver operating characteristic (ROC) curves, which indicated the ability to distinguish acceptable from unacceptable heat strain. Further analyses included factorial analysis of variance and exact conditional logistic regression. Based on the ROC curve analyses, the physiological metrics can distinguish between acceptable and unacceptable heat strain with average area under the curves between 0.529 and 0.861. While there were no differences among the metrics based on the 95% confidence intervals of the areas under the curve, the results were compromised by low power. Based on ANOVA and logistic regression, clothing did not influence the metrics. There were insufficient data to evaluate the role of heat stress level.

L’objectif de la présente thèse était de caractériser le sommeil d’un groupe clinique d’enfants et d’adolescents ayant un trouble d’anxiété comme diagnostic primaire et le comparer à un groupe témoin. Dans un premier temps, nous avons vérifié si le profil de la fréquence cardiaque nocturne des enfants et des adolescents pouvait être regroupé selon le diagnostic. Pour ce faire, la fréquence cardiaque nocturne de 67 adolescents anxieux et 19 sujets non anxieux a été enregistrée à l’aide d’un équipement ambulatoire. Les résultats de cette étude montrent que le profil de la fréquence cardiaque nocturne chez les enfants anxieux varie selon le diagnostic. Alors que les adolescents non anxieux montrent un profil de la fréquence cardiaque nocturne plat, on retrouve les associations suivantes chez les adolescents ayant un trouble anxieux : a) un profil croissant de la fréquence cardiaque chez les adolescents ayant un trouble d’anxiété de séparation; b) un profil décroissant de la fréquence cardiaque chez les adolescents ayant un trouble d’anxiété généralisé; c) un profil en forme de U chez les adolescents ayant un trouble d’anxiété sociale. De plus, une association significative a été observée entre le diagnostic et la présence de fatigue matinale. L’association d’un profil de la fréquence cardiaque nocturne avec un diagnostic d’anxiété suggère la présence d’une dysrégulation de la modulation chronobiologique du système nerveux autonome. Étant donné que le profil de la fréquence cardiaque nocturne s’exprime différemment selon le diagnostic, qu’en est-il de l’architecture du sommeil? Dans un deuxième temps, nous avons enregistré le sommeil en laboratoire d’un groupe clinique de 19 jeunes ayant un trouble d’anxiété comme diagnostic primaire, avec comorbidités et médication et comparé à 19 jeunes non anxieux. Les résultats de cette étude ont montré que les participants du groupe anxieux ont une latence au sommeil plus longue, une latence au sommeil paradoxal plus longue et une durée d’éveil plus longue lorsque comparé au groupe témoin. L’évaluation subjective de la qualité du sommeil chez le groupe d’adolescents anxieux montre que leur auto-évaluation reflète les valeurs enregistrées en laboratoire. Nous avons également observé chez le groupe anxieux une fréquence cardiaque moyenne plus élevée et un index plus élevé d’apnée-hypopnée, bien que non pathologique. Nous avons également observé une association positive entre l’anxiété de trait et l’indice d’apnée-hypopnée et la latence au sommeil, ainsi qu’une association positive entre l’anxiété manifeste et la latence au sommeil paradoxal. Ces résultats suggèrent que le sommeil chez cette population est altéré, que des signes d’hypervigilance physiologique sont présents et qu'une association existe entre ces deux paramètres. Finalement, dans la troisième étude de cette thèse, nous avons analysé l’activité cardiaque pendant le sommeil en utilisant les paramètres temporels et fréquentiels de la variabilité cardiaque chez un groupe clinique de dix-sept enfants et adolescents ayant un trouble d’anxiété comme diagnostic primaire avec comorbidité et médication, et comparé à un groupe non anxieux. Les résultats ont montré que les participants du groupe anxieux, lorsque comparés au groupe non anxieux, présentent des intervalles interbattements plus courts, un indice temporel de la variabilité cardiaque représentant la branche parasympathique moindre, une activité des hautes fréquences normalisées moindre et un ratio basse fréquence sur haute fréquence augmenté. Plusieurs corrélations ont été observées entre les mesures cliniques de l’anxiété et les mesures de la variabilité cardiaque. Ces résultats viennent ajouter à la littérature actuelle un volet descriptif clinique à ce jour non documenté, soit l’impact de l’anxiété pathologique chez un groupe clinique d’enfants et d’adolescents sur le processus normal du sommeil et sur la régulation de la fréquence cardiaque. En résumé, les résultats de ces trois études ont permis de documenter chez un groupe clinique d’enfants et d’adolescents ayant de l’anxiété pathologique, la présence d’une altération circadienne du profil de la fréquence cardiaque, d’une architecture altérée du sommeil ainsi qu’une dysrégulation du système nerveux contrôlant l’activité cardiaque. / The aim of this thesis was to characterize, in a clinical group of children and adolescents with anxiety disorder as a primary diagnostic, the sleep period and to compare it to a control group. Firstly, we have verified if the nocturnal sleep pattern of children and adolescents could be grouped by psychiatric disorders. Sixty-seven children and adolescents with anxiety disorders and nineteen non anxious match controls were monitored using ambulatory recording equipment. Results showed that nocturnal heart rate pattern of anxious adolescents would vary accordingly with the diagnosis. While non anxious adolescents exhibit a flat nocturnal heart rate pattern through the night, anxious participants showed the following associations: a) increased nocturnal heart rate pattern associated with separation anxiety disorder; b) decreased nocturnal heart rate pattern associated with generalized anxiety disorder; and c) U shape nocturnal heart rate pattern associated with social phobia. Moreover, a significant association was found between anxiety diagnosis and presence of morning fatigue. The association between nocturnal heart rate patterns with anxiety suggests that the circadian modulation of heart rate is dysregulated, but what about the sleep macrostructure? Secondly, we have monitored in a sleep laboratory a clinical sample of nineteen adolescents with pathological anxiety, comorbidity and medication, and compared it to nineteen non anxious match controls. Results showed that anxious participants had longer sleep latency, longer REM sleep latency and longer awake period during sleep when compared to control participants. Compared to control participants, anxious patients subjectively reported sleep disturbances, manifested objective sleep disorders and presented no adaptation to the laboratory environment. Moreover, higher nocturnal heart rate and higher apnea-hypopnea index were observed in anxious group when compared to non anxious group. Significant positive associations were observed between Trait anxiety and apnea-hypopnea index as well as for sleep latency while manifest anxiety was associated to REM sleep latency. Results suggest that sleep of children and adolescents with pathological anxiety is altered, that signs of physiological hypervigilance are observed and that both are associated. Following previous results, we have analyzed in a third study heart rate variability during nocturnal sleep using both, times and frequency domains in a clinical sample group of seventeen children and adolescents with anxiety disorder as primary diagnostic with comorbidity and medication. Results showed that anxious when compared to non anxious, had a shorter interbeat interval, and had lower rMSSD values, less high frequency in normalized units and higher low frequency/high frequency ratio. Correlations were observed between clinical anxiety scores and time and frequency domains of heart rate variability. These results add to the growing body of literature that pathological anxiety in a clinical group of children and adolescents impact on sleep process and heart rate regulation during sleep. Overall findings add to the growing body of recent clinical literature, a sleep alteration description of a clinical sample of children and adolescents. From the three studies of this thesis, results showed that circadian heart rate pattern is altered, that sleep architecture is altered, and that the time and frequency domain of nocturnal heart rate variability is altered in a clinical group of children and adolescents with pathological anxiety.

The potential to track changes in training status and fitness levels of especially team sport participants by making use of more time efficient and accessible methods such as heart rate variability (HRV) and heart rate recovery (HRR) cannot be overlooked and needs to be considered. However, studies that have investigated this aspect in team sport participants are scarce. It is against this background that the main objectives of this study were firstly, to determine the relationships between HRV and HRR as well as the fitness levels of a cohort of university-level rugby players. The second objective was to determine the validity of the BioForce Heart Rate Variability System to determine the HRV of a cohort of university-level rugby players. Twenty-four university-level rugby players (age: 20.1 ± 0.41 years; body stature: 182.7 ± 6.2 cm; body mass: 89.7 ± 12.7 kg) of a South African university’s Rugby Institute participated in the first part of the study. During the test day players’ fasting baseline HRV (baseline HRV) values were taken. This was followed by the measurement of the post-breakfast HRV (Pre-Yo-Yo IR1 HRV). Players were then required to perform the Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IR1) while they were fitted with a portable Cosmed K4b2 gas analyser apparatus and a Fix Polar Heart Rate Transmitter Belt. After completion of the test, HRR was taken on 1 and 3 minutes and followed by the measurement of HRV (Post-Yo-Yo IR1 HRV). For the second part of the study a group of twenty u/21 university-level rugby players (age: 20.06 ± 0.40 years; body stature: 181.8 ± 5.5 cm; body mass: 91.1 ± 10.7 kg) of a South African university’s Rugby Institute were recruited to participate in this study. HRV was measured simultaneously by the Actiheart monitor system as well as the BioForce Heart Rate Variability System over three times periods: during the morning in a fasting state just after players had woken up (baseline); in the morning just after the players ate breakfast (pre-anaerobic); after completion of a high-intensity anaerobic training session (post-anaerobic) and after completion of a 20 min recovery session (post-recovery). Significant correlations (p ≤ 0.05) were found between Pre-Yo-Yo IR1 HRV and heart rate (HR) at the respiratory compensation point (RCP-HR (bpm)) (r = -0.468) as well as oxygen uptake at the RCP (RCP- 2max VO (% of 2max VO )) (r = 0.476), respectively. A forward stepwise regression analysis showed that HR at ventilatory threshold 1 (VT1-HR (bpm)) contributed significantly (p ≤ 0.05) to the post-Yo-Yo IR1 HRV with a variance of 39.8%. Final Yo-Yo IR1 level also contributed significantly (p ≤ 0.05) to 3 minute post-Yo-Yo IR1 HRR with a variance of 16.5%. For the second part of the study the majority of significant relationships (p < 0.05) between the Actiheart and Bioforce obtained HRV results were observed for the post-recovery period (Mean RR, SDNN, RMSSD and Peak LF power), followed by the pre-anaerobic period (Mean R-R and SDNN) and the baseline period (LF:HF ratio). No significant relationships were observed between the HRV results of the two apparatuses during the post-anaerobic period. In conclusion, HRV and HRR may have the potential to act as affordable and easy measurement tools of team sport participants’ fitness levels. However, the study results suggested that the BioForce Heart Rate Variability System that is used to obtain team sport participants’ HRV is especially valid to determine HRV after recovery periods that follow hard training sessions. The results do however cast a shadow of doubt over the accuracy of this apparatus when used directly after hard training sessions. / MSc (Sport Science), North-West University, Potchefstroom Campus, 2014

Emotions are an integral part of the human experience and their interpretation can provide valuable but also misleading clues about oneself and other people’s state of mind. Negative emotional states can be perceived as uncomfortable and – when experienced chronically – can develop into anxiety and mood disorders. The more pervasive these disorders the more severely they affect and disable a person’s everyday functioning and often their sleep as well. According to Lang and colleagues (1998), emotions may be expressed verbally, behaviorally, and physiologically, i.e., emotions can be reported, observed, and objectively measured. Each measurement approach provides important, unique, and often conflicting information that can be used in the assessment and treatment evaluation of psychological disorders affecting the emotions. Autonomic measures have been used to indicate the physiological components of emotions, such as those along the worry-anxiety-fear-panic spectrum. Worry has been shown to suppress cardiac responses to imaginal feared material (see Borkovec, Alcaine, & Behar, 2004) and reduce autonomic variability (Hoehn-Saric, McLeod, Funderburk, & Kowalski, 2004; Hoehn-Saric, McLeod, & Zimmerli, 1989). Results for panic and anticipatory anxiety are less conclusive but theoretically these states should go along with increased autonomic arousal. Abnormal autonomic arousal might also be present during sleep as both panic disorder and worrying have been associated with sleeping difficulties. However, most empirical research has been confined to the laboratory where high internal validity is achieved at the cost of poor ecological validity. Thus, the purpose of this doctoral dissertation is to extend and validate laboratory findings on worry, anticipatory anxiety, and panic using ambulatory monitoring. Twenty-four hour monitoring not only can give valuable insights into a person’s daytime emotional experience but also allows observing how these emotions might affect their sleep in their natural environment. In the following chapter, the reader will be introduced to a conceptual framework that ties together worry, anxiety, fear, and panic, and related anxiety disorders (section 2.1), to autonomic arousal and electrodermal and cardiac arousal in particular (section 2.2), to sleep and its relation to autonomic arousal and anxiety disorders (section 2.3), and to ambulatory monitoring (section 2.4). After illustrating the aims of this thesis (chapter 3), chapters 4 to 6 present the results of three empirical studies conducted as part of this doctoral research. The first study deals solely with electrodermal monitoring and how it is affected by confounding variables in an ambulatory context (chapter 4). The next study then seeks to investigate the relationship between electrodermal arousal and anticipatory anxiety and panic in a sample of panic disorder patients and healthy controls. The last study focuses primarily on the effect of trait and state worry on subjective and objective sleep and electrodermal and cardiac arousal in a group of high and low worriers. Chapters 7 to 9 summarize and integrate the findings from these three empirical studies, discuss methodological limitations, and provide an outlook into future research.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 5 uppsatser.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-06-22T17:42:42Z No. of bitstreams: 1 jussarareginapereirabritto.pdf: 2008279 bytes, checksum: 81f1e8b058921cfb73367f7e41a7ae65 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-08-07T19:23:25Z (GMT) No. of bitstreams: 1 jussarareginapereirabritto.pdf: 2008279 bytes, checksum: 81f1e8b058921cfb73367f7e41a7ae65 (MD5) / Made available in DSpace on 2017-08-07T19:23:25Z (GMT). No. of bitstreams: 1 jussarareginapereirabritto.pdf: 2008279 bytes, checksum: 81f1e8b058921cfb73367f7e41a7ae65 (MD5) Previous issue date: 2014-08-25 / Os amputados traumáticos de membros inferiores apresentam maior morbidade e mortalidade por doenças cardiovasculares quando comparados à população geral. Entretanto, os fatores de risco para esse aumento de morbidade, bem como os mecanismos patofisiológicos responsáveis, ainda não estão bem esclarecidos. O objetivo do presente estudo foi testar as hipóteses que o uso da prótese em amputados transtibiais traumáticos aumenta a pressão arterial (PA) e a frequência cardíaca (FC) e diminui a variabilidade da frequência cardíaca (VFC), na postura supina (PS) e postura ortostática (PO). Foram avaliados 20 indivíduos adultos, do sexo masculino, sendo 10 com amputações transtibiais unilaterais traumáticas e 10 indivíduos sem amputações (controles). O registro da FC, para o cálculo das medidas de VFC, foi realizado por meio do monitor de frequência cardíaca Polar® modelo RS300CX e a PA foi aferida pelo método auscultatório e oscilométrico. Os grupos foram avaliados em repouso, na PS e PO, sendo os amputados submetidos ao protocolo com e sem a prótese. Para comparações intragrupo foi realizada a ANOVA 2x2 de medidas repetidas e testes t pareados; e na comparação entre grupos, utilizou-se o teste t de Student para amostras independentes. O grupo amputados, com e sem a prótese, foi observado que a FC é maior na PO comparada a PS, (82,5 ± 11,1 vs. 66,8 ± 6,7 bpm respectivamente) e que ao utilizarem a prótese a FC foi maior comparada à condição sem prótese, (76,8 ± 9,0 vs. 72,5 ± 8,0 bpm respectivamente). Analisando as variáveis autonômicas dos amputados na PO comparada a PS, eles apresentaram menores valores de iRR (763,0 ± 100,3 vs. 911,0 ± 89,9; p < 0,001), rMSSD (23,0 ± 14,0 vs. 37,7 ± 21,5; p = 0,001), pNN50 (5,9 ± 9,4 vs. 16,8 ± 18,6; p = 0,01) e HF (24,5 ± 15,0 vs. 42,8 ± 18,8; p = 0,02) e maiores valores de LF (77,1 ± 12,7 vs. 57,2 ± 18,8; p = 0,04) e LF/HF (5,9 ± 5,7 vs. 2,1 ± 1,7; p = 0,07). Quanto ao uso de prótese, foram observados menores valores de iRR (814,6 ± 92,2 vs. 859,4 ± 92,2; p = 0,001), rMSSD (26,6 ± 14,8 vs. 34,2 ± 20,1; p = 0,002) e pNN50 (8,9 ± 11,9 vs. 13,7 ± 15,4; p = 0,005) em comparação com a condição sem prótese. Comparando ao grupo controle, a FC dos amputados com o uso da prótese foi maior tanto na PS quanto na PO, ao passo que quando a prótese foi retirada, essa diferença desaparecia. Conclui-se que o uso da prótese altera as variáveis hemodinâmicas por meio do aumento da FC e da PA e das variáveis autonômicas por meio da redução da VFC. / The traumatic lower limb amputees have higher morbidity and mortality from cardiovascular disease compared to the general population. However, the risk factors for this increased morbidity, as well as the pathophysiological mechanisms responsible are not well understood. The aim of this study was to test the hypothesis that the use of the prosthesis in transtibial amputees traumatic increases blood pressure (BP) and heart rate (HR) and decreased heart rate variability (HRV) in the supine posture (PS) and standing position (PO). 20 individuals, males, 10 with unilateral transtibial amputations and traumatic amputations 10 individuals without (controls) were evaluated. The registration of the FC, for the calculation of measures of HRV was performed by means of the heart rate Polar ® RS300CX model and BP monitor was checked by auscultation and oscillometry. The groups were evaluated at rest, the PS and PO, being amputees undergoing the protocol with and without the prosthesis. For intragroup comparisons 2x2 ANOVA repeated measures and paired t tests were performed; and comparison groups was used for independent samples Student's t test. The amputee group, with or without the prosthesis, it was found that FC is larger compared to PO the PS (82.5 ± 11.1 vs. 66.8 ± 6.7 beats per minute respectively) and that when using the prosthesis HR was higher compared to unaided, (76.8 ± 9.0 vs. 72.5 ± 8.0 bpm respectively). Analyzing the autonomic variables of amputees in PO compared to PS, they had lower values of RR intervals (763.0 ± 100.3 vs. 911.0 ± 89.9, p <0.001), rMSSD (23.0 ± 14.0 vs. 37.7 ± 21.5, p = 0.001), pNN50 (5.9 ± 9.4 vs. 16.8 ± 18.6, p = 0.01) and HF (24.5 ± 15.0 vs. 42.8 ± 18.8, p = 0.02) and higher values of LF (77.1 ± 12.7 vs. 57.2 ± 18.8, p = 0.04) and LF / HF (5.9 ± 5.7 vs. 2.1 ± 1.7, p = 0.07). Regarding the use of prosthesis, lower values of RR intervals (814.6 ± 92.2 vs. 859.4 ± 92.2, p = 0.001) were observed, rMSSD (26.6 ± 14.8 vs. 34.2 ± 20.1, p = 0.002) and pNN50 (11.9 ± 8.9 vs. 13.7 ± 15.4, p = 0.005) compared to the unaided. Compared to the control group, HR amputees using prostheses was higher both in PS as in PO, whereas when the prosthesis was removed, this difference disappeared. We conclude that the use of the prosthesis alters hemodynamic variables by increasing HR and BP and autonomic variables by reduced HRV.

Este trabalho teve por objetivo avaliar a modulação autonômica da freqüência cardíaca (FC) durante o repouso, nas posições supina e sentada, e durante teste de esforço físico dinâmico descontínuo do tipo degrau (TEFDD-D) em mulheres jovens e pós-menopausa sem (PMSRH) e com reposição hormonal (PMCRH); determinar o limiar de anaerobiose (LA) a partir da análise das respostas de FC e pela análise dos índices de RMSSD (raiz quadrada da média dos quadrados das diferenças entre os intervalos R-R normais sucessivos), em milissegundos (ms), e comparar o grau de correlação entre estas duas metodologias de análise. Foram estudadas 11 jovens (24 ± 2,77 anos), 13 PMSRH (57 ± 5,28) e 9 PMCRH (55 ± 5,40 anos). O TEFDD-D foi realizado em cicloergômetro, sendo iniciado com a potência de 15 W e com incrementos de 5 em 5 W. A FC (bpm) e os intervalos R-R (ms) foram captados em tempo real, por um período de 360s em repouso, em cada posição, e durante 60s em repouso sentado no cicloergômetro, 240s em exercício e 60s em recuperação, em cada potência do TEFDD-D. Foram calculados as médias da FC (bpm) e os índices de RMSSD dos intervalos R-R (ms) para as condições de repouso e durante 180s do exercício nas potências estudadas; cálculo da variação da FC (bpm) no início do exercício e do tempo (s) desta variação. A determinação do LA foi feita pelo ajuste do modelo matemático e estatístico semiparamétrico (SPM) aos dados de FC e pelos índices de RMSSD dos intervalos R-R (ms). Os testes estatísticos utilizados foram: Wilcoxon, Kruskall-Wallis, Friedman, Dunn e o teste de correlação de Spearman, nível de significância de 5%. Durante o repouso, as jovens apresentaram valores dos índices de RMSSD significativamente (p<0,05) superiores em relação aos outros 2 grupos. As variações da FC das jovens no início do exercício foram maiores que as dos grupos PMSRH e PMCRH, enquanto que o tempo de variação da FC foi similar entre os 3 grupos. Na transição do repouso para o exercício, a FC aumentou progressivamente, enquanto que a variabilidade da freqüência cardíaca (VFC) diminuiu. Na comparação intergrupo dos índices de RMSSD, obtidos em cada nível de potência, foi observada diferença significativa (p<0,05) apenas em 35W. Tanto pelo modelo SPM, como pela análise dos índices de RMSSD, as jovens atingiram o LA em potências superiores comparativamente as PMSRH e PMCRH. Os grupos PMSRH e PMCRH apresentaram resultados similares. Não foram observadas diferenças significativas (p>0,05) na comparação dos 2 métodos. O teste de correlação de Spearman mostrou uma associação significativa (p<0,05) entre os mesmos. Estes dados sugerem que após a menopausa ocorre uma diminuição da modulação vagal sobre o coração tanto em repouso como durante o exercício físico, decorrente do processo do envelhecimento e da redução da capacidade física. A terapia de reposição hormonal não teve nenhuma influência sobre os resultados. As duas metodologias de análise do LA se mostraram similares, sugerindo que a mudança de inclinação da resposta da FC ocorre em níveis de esforço em que a VFC se encontra significativamente reduzida. / The objectives of the present study were to assess the autonomic modulation of the heart rate (HR) at rest, in the supine and sitting position, and during a step type discontinuous dynamic physical effort (STDDPE) in young and postmenopausal women not receiving (PMWtHR) and receiving hormonal replacement treatment (PMWHR); to determine the anaerobiosis threshold (AT) based on the analysis of HR response and the RMSSD indices (square root of the mean squared differences of successive R-R intervals), in milliseconds (ms), and to compare the degree of correlation between these two analysis methodologies. The study was conducted on 11 young women (24 ± 2.77 years), 13 PMWtHR (57 ± 5.28) and 9 PMWHR (55 ± 5.40 years). The STDDPE was performed on a bicycle ergometer at an initial power of 15 W, followed by power increments of 5 W. HR (bpm) and R-R intervals (ms) were obtained in real time over a period of 360 s under resting conditions in each position, during 60 s in the sitting rest position on the bicycle ergometer, 240 s during exercise and 60 s during recuperation at each STDDPE power. Mean HR (bpm) and RMSSD indices of the R-R intervals (ms) were calculated for the resting condition and during 180 s of exercise in the powers studied; the HR variation (bpm) and its time (s) were also calculated in the beginning of exercise. AT was determined by the semiparametric mathematical and statistical model (PMS) and by the RMSSD indices of the R-R intervals (ms). Data were analyzed statistically by the Wilcoxon, Kruskal-Wallis, Friedman, Dunn and Spearman correlation tests, with the level of significance set at 5%. During rest, young women presented significantly higher RMSSD indices (p<0.05) than the other 2 groups. The HR variations in young women in the beginning of the exercise were higher than the ones from the PMWtHR and PMWHR groups, whereas HR variations time was similar for the 3 groups. During the transition from rest to exercise HR increased progressively and HRV decreased. Intergroup comparison of RMSSD indices, obtained in each level of power, showed a significant difference (p<0.05) only at 35 W power. On both PMS model and RMSSD indices analysis, young women reached AT at a higher power compared to PMWtHR and PMWHR groups. The PMWtHR and PMWHR groups presented similar results. No significant differences (p>0.05) were observed when the methods were compared. The Spearman correlation test showed a significant association (p<0.05) between methods. These data suggest that after menopause there is a decrease in vagal modulation of the heart both at rest and during physical exercise due to the aging process and the reduction in physical capacity. Hormonal replacement therapy had no effect on the results. Both methodologies of AT analysis were similar, suggesting that the change in the HR response occurs in levels of effort in which the HRV is significantly reduced.

Physical health can be measured in several ways both based on subjective experiences and with objective tools. However, mental health can only be measured through subjective experiences and sensations, which can be biased. Therefore, researchers adopted the notion of an objective tool to assess well-being as a complement to existing self-reported scales and suggested that heart rate variability (HRV) might be an indicator of well-being. Hence, this thesis investigates the relationship between subjective well-being (SWB) and HRV, particularly high frequency-HRV (HF-HRV). Three hypotheses, which included different forms of well-being, were developed to test the relationship. And the hypotheses were: Cognitive well-being correlates positively with HF-HRV. Positive affect correlates positively with HF-HRV, and negative affect correlates negatively with HF-HRV. A total of 19 healthy Swedish females aged from 20-35 participated and answered questionnaires measuring SWB. After they completed the SWB-scales, their heart rate was measured and then converted into HF-HRV data. The findings revealed no correlations between the cognitive SWB and HF-HRV, neither to affective SWB.

The aim of this master’s thesis is to analyse methods that are used for monitoring athlete’s activities and a description of current technical solutions with a focus on heart rate and respiratory rate monitoring. The presented solution shows the possibilities of using available open source SW and HW technologies and their implementation in the design of an integrated tool for monitoring sports activities with the iOS operating system.