This study investigates the effects of isotonic and isometric exercises on heart rate and blood pressure and seeks to determine the relationship of these effects to physical work capacity.

Electrodermal responding (EDR) and heart rate (HR) were assessed for seven subjects participating in a reaction time task consequated with monetary bonuses (250, 100, and 10), monetary penalties (250,100, and 10), and a monetary neutral value (00). Unlike previous research employing group designs and a tonic measure (i.e., mean over long periods of time), this study utilized a single-subject design and a phasic measure (i.e., mean over 2-s intervals). Heart rate data was too variable for meaningful analysis. EDR data showed that the peak levels of EDR were higher for penalties than for the corresponding values of bonuses (e.g., -250 vs. +250) for most subjects. Similarly, peak levels of EDR were generally higher during sessions in which consequences were presented than in sessions during which consequences were absent.

This study presents the findings of an investigation of the effects of two different treatments, progressive relaxation and cerebral electrotherapy, on heart rate. With progressive relaxation, the subject relaxes by following instructions. With cerebral electrotherapy, relaxation is due to an external source of stimulation. Decreases in heart rate for subjects receiving progressive relaxation were compared with decreases for subjects receiving cerebral electrotherapy. A placebo group was used to evaluate the effects of both treatments independently. While decreases in heart rate were observed for both treatments, only progressive relaxation produced decreases significantly greater than those of the placebo group. However, decreases in heart rate produced by progressive relaxation were not significantly greater than decreases produced by cerebral electrotherapy.

Writing about a personal traumatic event has been found to have psychological and physical health benefits. Focusing on traumatic memories in writing may be a form of exposure. In imagery exposure and trauma writing, greater physiological reactivity was predictive of better outcomes. Given the importance of physiological output in emotional processing, response training was developed and found to be effective in increasing appropriate physiological reactivity in imagery exposure. If response training amplifies physiological reactivity and the benefits of writing, the hypothesis that writing is a form of exposure would be strengthened, and training may be a valuable tool to improve the efficacy of psychotherapy approaches that use writing as a form of exposure. The present study examined whether response training enhances the benefits of trauma writing. In this study, participants wrote for 20 minutes on three occasions about a personal traumatic event (n = 113) or a trivial topic (n = 133) and received response imagery training (n = 79), stimulus imagery training (n = 84) or no training (n = 83). Heart rate and skin conductance were recorded in sessions one and three throughout a 10-minute baseline, writing, and a ten-minute recovery period. Self-reported trauma symptoms and emotion were assessed in each session. One month after completing the sessions, participants completed follow-up assessments of psychological and physical health outcomes. As predicted, trauma writing elicited greater physiological reactivity and self-reported trauma symptoms and emotion than neutral writing. Response training amplified physiological reactivity to trauma writing more than neutral writing, without amplifying levels of self-reported emotion or trauma symptoms. The physiological reactivity and self-reported emotion elicited by trauma writing habituated across sessions and response training enhanced these effects. Finally, increased heart rate predicted better outcomes for all trauma writers; however, response trained trauma writers who evidenced greater heart rate showed the greatest reductions in trauma, depression and physical illness symptoms at follow-up. These results support previous research which found that greater physiological reactivity was predictive of writing outcomes. The findings are the first to demonstrate that response training facilitates emotional processing and thus may be a beneficial adjunct to trauma writing.

Writing about personal traumatic experiences is associated with beneficial effects on physical and psychological symptoms compared with writing about emotionally neutral events. However, not everyone benefits from trauma writing to the same extent. The present study hypothesized that the effectiveness of trauma writing may be moderated by emotion regulation, as indexed by respiratory sinus arrhythmia (RSA). Research also shows that greater physiological reactivity is predictive of better trauma writing outcomes. Given the importance of physiological output in emotional processing, response training was developed and found to increase appropriate physiological reactivity. Because higher RSA is thought to indicate a more flexible response style including processing both emotional and physiological cues, it was hypothesized that trauma writers with higher resting RSA who received response training (as opposed to stimulus or no training) would have the best outcomes. It was also predicted that higher resting RSA would be related to lower baseline levels of depression, posttraumatic stress disorder (PTSD), physical illness symptoms, heart rate, and skin conductance. In the current study, participants wrote for 20 minutes on three occasions about a personal traumatic event (n = 113) or a neutral topic (n = 133) and received response training (n = 79), stimulus training (n = 84) or no training (n = 83). Heart rate and skin conductance were recorded in sessions one and three during a 10-minute baseline, 20-minute writing, and 10-minute recovery period. Self-reported trauma symptoms were assessed in each session. At baseline and one month after completing the sessions, participants filled out assessments of depression, PTSD, and physical illness symptoms. As predicted, participants with higher resting RSA who wrote about a trauma had greater reductions in symptoms of PTSD at post-writing session three. Higher resting RSA was also related to lower levels of resting heart rate and skin conductance. No relation was found between RSA and baseline symptoms of depression, PTSD, and physical illness. This study also found no effect of resting RSA as a moderator of response training outcomes.

PROBLEM STATEMENT: Growing evidence indicates that psychological stress contributes to cardiovascular diseases through complex neuroendocrine mechanisms. Psychological stress leads to several physiological responses including increased heart rate (HR) and blood pressure (BP) as well as decreased heart rate variability (HRV) through alterations in the autonomic nervous system (ANS), specifically increased sympathetic nervous system (SNS) activity and decreased parasympathetic nervous system (PNS) activity. Meditation is thought to induce an innate relaxation response leading to reduced psychological stress. Findings from past studies have provided inconclusive evidence regarding the direction and strength of relationships among stress, BP, HRV, and meditation practice. PROCEDURES: A cross-sectional descriptive-correlational design was used to examine relationships among perceived stress, BP, HRV and meditation practice in meditators. A convenience sample of 71 meditators at two meditation centers in the southeast United States was used. Sample size was based on a power analysis. Each participant was asked to complete meditation, perceived stress, and demographic questionnaires. Participants' BP was measured before meditation and HRV was recorded during a 30 minute meditation session. Finally, BP was recorded after meditation. RESULTS: Participants were predominantly female (55%), Caucasian/white (94%), and Buddhist (76%), with 93% having at least college graduate. Most participants practiced soto zen or vipassana meditation (45% and 30%, respectively). The average length of total meditation practice was 103.66 months. Participants practiced meditation an average of once a day for 4 days a week with mean session duration of 34 minutes. Most participants had a low level of perceived stress and normal HRV. There was a statistically significant decrease in mean systolic BP after meditation (t = 5.31, p CONCLUSIONS: The results suggested meditators had low levels of perceived stress and that meditation had an effect on systolic BP and perceived current stress. Future research needs to include longitudinal studies to elucidate the cumulative effects of consistent meditation practice on psychological and physiological outcomes.

Over the last 20 years, much work has focused on computer-aided clinical decision support systems due to a rapid increase in the need for management and processing of medical knowledge. Among all fields of medicine, trauma care has the highest need for proper information management due to the high prevalence of complex, life-threatening injuries. In particular, hemorrhage, which is encountered in most traumatic injuries, is a dominant factor in determining survival in both civilian and military settings. This complication can be better managed using a more in-depth analysis of patient information. Trauma physicians must make precise and rapid decisions, while considering a large number of patient variables and dealing with stressful environments. The ability of a computer-aided decision making system to rapidly analyze a patient’s condition can enable physicians to make more accurate decisions and thereby significantly improve the quality of care provided to patients. The first part of this study is focused on classification of highly complex databases using a hierarchical method which combines two complementary techniques: logistic regression and machine learning. This method, hereafter referred to as Classification Using Significant Features (CUSF), includes a statistical process to select the most significant variables from the correlated database. Then a machine learning algorithm is used to identify the data into classes using only the significant variables. As the main application addressed by CUSF, a set of computer-assisted rule-based trauma decision making system are designed. Computer aided decision-making system not only provides vital assistance for physicians in making fast and accurate decisions, proposed decisions are supported by transparent reasoning, but also can confirm a physicians’ current knowledge, enabling them to detect complex patterns and information which may reveal new knowledge not easily visible to the human eyes. The second part of this study proposes an algorithm based on a set of novel wavelet features to analyze physiological signals, such as Electrocardiograms (ECGs) that can provide invaluable information typically invisible to human eyes. These wavelet-based method, hereafter referred to as Signal Analysis Based on Wavelet-Extracted Features (SABWEF), extracts information that can be used to detect and analyze complex patterns that other methods such as Fourier cannot deal with. For instance, SABWEF can evaluate the severity of hemorrhagic shock (HS) from ECG, while the traditional technique of applying power spectrum density (PSD) and fractal dimension (FD) cannot distinguish between the ECG patterns of patients with HS (i.e. blood loss), and those of subjects undergoing physical activity. In this study, as the main application of SABWEF, ECG is analyzed to distinguish between HS and physical activity, and show that SABWEF can be used in both civilian and military settings to detect HS and its extent. This is the first reported use of an ECG analysis method to classify blood volume loss. SABWEF has the capability to rapidly determine the degree of volume loss from hemorrhage, providing the chance for more rapid remote triage and decision making.

Background: The majority of Americans - especially women - do not meet physical activity recommendations. Having physical activity goals has been associated with physical activity participation, and physical activity recommendations set by public health experts can be viewed as externally set goals. However, past research has shown that goals that are specific rather than ambiguous are more likely to be achieved, and variations in recommendations over time and across sources may have created perceived goal ambiguity.Objectives: This study aimed to (1) examine the extent of physical activity recommendation knowledge among adults in the United States, (2) quantify perceptions of the ambiguity of these recommendations, (3) determine whether knowledge of physical activity recommendations is associated with physical activity level, and (4) investigate whether perceived ambiguity of recommendations moderates the relationship between recommendation knowledge and activity. An additional objective was to explore demographic differences in any associations detected.Methods: SUDAAN was used to weight data from the 2005 Health Information National Trends Survey (HINTS) (N=5,586) to represent the U.S. population. Descriptive statistics were calculated, and logistic regression was used to determine crude and adjusted odds ratios.Results: An estimated 31% of Americans had accurate knowledge of recommendations, and 35% reported engaging in physical activity at the recommended level. An estimated 75% perceived the recommendations as ambiguous. The odds of reporting accurate knowledge of recommendations were significantly higher among women than among men (OR 1.53,95% CI 1.22-1.93), but accurate knowledge of recommendations was associated with physical activity at the recommended level only among men (OR 1.67,95% CI 1.06-2.64). Perceived ambiguity did not moderate the association between knowledge and activity level in any analysis.Conclusions: These findings support disseminating updated physical activity recommendations as indicated by the scientific evidence base. Future research should explore: (1) how to boost knowledge of recommendations, particularly in men, (2) factors that would enable women to act on such knowledge, and (3) gender differences in other determinants of physical activity.

In many applications of random-effects models to longitudinal data, such as heart rate variability (HRV) data, a normal-mixture distribution seems to be more appropriate than the normal distribution assumption. While the random-effects methodology is well developed for several distributions in the exponential family, the case of the normal-mixture has not been dealt with adequately in the literature. The models and the estimation methods that have been proposed in the past assume the conditional model (fixing the random-effects) to be normal and allow a mixture distribution for the random effects (Xu and Hedeker, 2001, Xu, 1995). The methods proposed in this dissertation assume the conditional model to be a normal-mixture while the random-effects are assumed to be normal. This is primarily to fit the HRV data, which seems to follow a normal-mixture within subjects. Another advantage of this model is that the estimation becomes much simpler through the use of an EM-algorithm. Existing methods and software such as the PROC MIXED in SAS are exploited to facilitate the estimation procedure.A simulation study is performed to examine the properties of the random-effects model with normal-mixture distribution and the estimation of the parameters using the EM-algorithm. The study shows that the estimates have similar properties to the usual normal random-effects models. The between subject variance parameter seems to require larger numbers of subjects to achieve reasonable accuracy, which is typical in all random-effects models.The HRV data is used to illustrate the random-effects normal-mixture method. These data consist of 9 subjects who completed a series of five speech tasks (Cacioppo et al., 2002). For each of the tasks, a series of RR-intervals was collected during baseline, preparation, and delivery periods. Information about their age and gender were also available. The random-effects mixture model presented in this dissertation treats the subjects as random and models age, gender, task, type, and task × type as fixed-effects. The analysis leads to the conclusion that all the fixed effects are statistically significant. The model further indicates a two-component normal-mixture with the same mixture proportion across individuals fit the data adequately.

La variabilité du rythme cardiaque « Heart Rate Variability (HRV) » consiste en des fluctuations perpétuelles du rythme cardiaque autour de sa fréquence moyenne. L’analyse de l’HRV constitue un biomarqueur du fonctionnement du système nerveux autonome (SNA), par l’intermédiaire de ses effets sur le cœur. De nombreuses études ont montré qu’une diminution de l’HRV est associée à un pronostic péjoratif, notamment dans le post infarctus et dans l’insuffisance cardiaque (IC). Nous nous sommes proposés d’élargir le champ d’investigation de l’HRV à de nouveaux domaines d’application, qu'il s'agisse de pathologies cardiaque ou extra cardiaque. Nous avons ciblé des contextes pathologiques dans lesquels le SNA joue un rôle important : 1-Accidents sur la Voie Publique (AVP) et le risque de développement d’un syndrome de stress post traumatique (PTSD). 2-Effet de la douleur et de l’analgésie péridurale sur l’HRV maternelle au cours de l’accouchement. 3-Lien avec les polymorphismes génétique des récepteurs bêta adrénergiques (β;-AR) chez des patients présentant une dysfonction ventriculaire gauche et implanté d’un défibrillateur automatique implantable (DAI) en prévention secondaire. L'analyse temporelle de l'HRV sur 24 heures est un facteur prédictif de survenue d'un PTSD et aussi de sa sévérité chez les victimes d'AVP. L'indice de variabilité est le meilleur paramètre prédictif de PTSD à 6 mois, avec une aire sous la courbe de 0.92 (IC 95% : 0.785; 1.046). Le seuil de 2.19% confère une sensibilité de 85,7 £ et une spécificité e 81.8 % pour prédire la survenue d'un PTSD. les valeurs prédictives positives et négatives sont de 75 % et 90 % respectivement. L'ANI, reflétant l'influence de la ventilation sur le rythme cardiaque, permet une mesure objective de la douleur chez les parturientes. Enfin, les patients ayant subi les substitutions Arg (pour Gly) en 16 et Gln (pour Glu) en 27 pour les récepteurs β2-AR, présentent une HRV plus faible que les patients ayant la forme sauvage du gène. / The heart rate variability (HRV) has arisen as a promising simple and non invasive biomarker of autonomic nervous system (ANS) function, through its effects on the heart. Multiple studies have shown that the decrease in the HRV is associated usually with poor prognosis. We proposed to further investigate the HRV in other domains of clinical application, including cardiac or extra-cardiac pathologies. In particular, the pathological contexts in which the ANS plays an important role :1-Traffic road accident (RTA) and the risk of development of post traumatic stress disorders (PTSD) in survivors.2-Effect of pain and of epidural analgesia on maternal HRV during childbirth.3-Genetic polymorphisms of beta adrenergic receptors (β-AR) in patients with left ventricular dysfunction and implanted with an implantable cardioverter defibrillator (ICD) for secondary prevention. At first, our study is the first to show that the temporal analysis of 24-h HRV is not only a predictive factor of the occurrence of PTSD but also its severity among victims of RTA AVP. The variability index was the best predictor of PTSD with the area under the receiver-operating curve for discriminating PTSD at 6 month at 0.92 (95% CI:0.785;1.046). Acut-off at 2.19% yielded a sensitivity of 85.7% and a specificity of 81.8% for PTSD. Positive and negative predictive values were respectively 75% and 90%. At next, we showed that the ANI, which reflects the influence of ventilation on heart rate, allows an objective measure of pain in conscious subjects? At last, we found that patients with the substitutions Arg (instead of Gly) at position 16 and Gln (instead of Glu) at position 27 for β2-AR have a lower HRV value than patients with wild type receptor.