The purpose of this study was to disentangle the psychobiological mechanisms and social-evaluative conditions that mediate the process by which the Autonomic Nervous System reacts in male and female humans. We used the original Trier Social Stress Test, as well as two modifications to this original social stressor: a punishment modification and a reward modification. We obtained measures of autonomic (heart rate and respiratory sinus arrhythmia; HR and SA respectively) reactivity before, during and after the stress test. To distinguish the contribution of the different modifications and any additional difference in reactivity due to gender, the participants were randomly separated into the three modifications, where N=35 (17 male) for the no modification group, N=12 (7 male) for the punishment condition, and N=13 (8 male) for the reward condition. All participants exhibited ANS reactivity to the stressor; females exhibited the most magnified response to all modifications. Overall, the most ANS reactivity was found within the reward condition, with the no modification group exhibiting the least amount of reactivity. This suggests that the reward paradigm was the most salient of all the stressors. Evidence indicated that the ANS stress response system is highly sensitive to potential for gain and reward, especially in females.

Die vorliegende Arbeit untersuchte die Entwicklung nieder-und hochfrequenter rhythmischer kardiorespiratorischer gesunder Säuglinge. An 15 Probanden erfolgten im Schlaf im ersten Lebenshalbjahr jeweils 13 Messungen mit EKG-Ableitung und induktionsplethysmographischer Registrierung der thorakalen Atemexkursion. Schlafstadienbezogen erfolgten: · die Messung der Amplitude der respiratorischen Sinusarrhythmie (RSA), · die Bestimmung der größten negativen Korrelation zwischen Atemsignal und Herzperiodendauer-Zeitreihe (Kreuzkorrelationskoeffizient, KKK) mit der dazugehörigen Phasenverschiebung mittels Berechnung der Kreuzkorrelationsfunktion und · die Auswertung der Kohärenzspektren von Atmung und Herzaktion. RSA und KKK im ruhigen Schlaf nehmen im Verlauf des ersten Lebenshalbjahres zu. Der Verlauf ist nicht geradlinig, sondern weist signifikante Minima in den ersten Lebenstagen und am Ende der dritten Lebenswoche auf. Die Phasenverschiebung zwischen Atmung und RSA zeigt im ruhigen Schlaf Maxima am 7. und 21. Lebenstag ohne deutlichen Trend innerhalb des Beobachtungszeitraumes. RSA und KKK sind vom ersten Lebenstag an mit Atemfrequenz und Herzfrequenz negativ korreliert. RSA und KKK sind schlafstadienabhängig. Im Gegensatz zum ruhigen Schlaf konnte im aktiven Schlaf weder eine meßbare RSA, noch ein signifikanter KKK gefunden werden. Im Kohärenzspektrum waren jedoch ab dem 150. Lebenstag auch im aktiven Schlaf signifikante gemeinsame Rhythmen im Atemfrequenzbereich nachweisbar. Mit Hilfe der Kohärenzspektren konnten gemeinsame niederfrequente Rhythmen in Atmung und Herzaktion nur in 5.1 % aller Messungen im ruhigen Schlaf und nur in 3.1 % im aktiven Schlaf nachgewiesen werden. Die untersuchten Parameter der Interaktion von Atmung und Herzfrequenz Neugeborener unterscheiden sich von denen Erwachsener in den Absolutwerten. Für RSA und Phasenverschiebung konnte zeigte sich jedoch, daß sich die Werte Erwachsener und Neugeborener nur an verschiedenen Punkten einer gemeinsamen "Arbeitskurve" befinden. Die Ergebnisse lassen auf eine schon zum Zeitpunkt der Geburt vorhandene Reife der kardiorespiratorischen Interaktion schließen. / In the present paper the development of rhythmic cardiorespiratory interactions in low and high frequency ranges were investigated in healthy infants. Data come from a longitudinal study of 14 infants, who were examined for 13 times during sleep during the first 6 months of live. The electrocardiogram and the thoracic respiratory effort were recorded. For quiet and active sleep the following parameters of cardiorespiratory interaction were analysed: · the amplitude of respiratory sinus arrhythmia (RSA), · the highest negative correlation (KKK) and the corresponding phase delay between respiratory signal and time series of heart period duration by means of calculating the cross correlation function and · the coherence in the low and high frequency range. RSA and KKK increase in the first 6 months of live. The course is not linear and has maxima in the first days and at the end of third week. The phase delay shows maxima at 7 th and 21 st day. RSA and KKK are negatively correlated with the respiratory rate and the heart rate from the first day of life up to the 6 th month of life. RSA and KKK depend on sleep state. In opposition to quiet sleep in active sleep neither a measurable RSA nor a significant KKK were found. Contrary, the coherence spectra showed common rhythms in the frequency range of the respiratory rate in the 5 th and 6 th month during active sleep. In the low frequency range common rhythms were observed only seldom, i.e. in 5.1 % of all measurements during quiet sleep and in 3.1 % during active sleep. The analysed parameters of cardiorespiratory interaction of newborns are different from that of adults regarding the absolute values. However the data suggest that the values of newborns and adults represent only different adjustments of a comparable control system. The results indicate a mature cardiorespiratory interaction in healthy newborns.

Abstract A cardiorespiratory system is highly regulated via the autonomic nervous system (ANS), whose function can be quantified noninvasively by analyzing electrocardiogram (ECG), blood pressure (BP) and respiration signals. Several conditions and illnesses are linked with imbalance of the ANS. This thesis aimed to develop methods for describing the ANS regulation of a cardiovascular system from short-term cardiorespiratory measurements. More specifically, the role of breathing rate and its effects on traditional frequency domain based cardiovascular indexes describing ANS control is addressed. The main contributions are as follows: 1) an adaptive filtering based method to remove respiratory influences from cardiovascular signals and indexes was developed. The adaptive filter reduced the bias caused by low respiration rate, enabling the usage of spontaneous respiration measurement protocol over controlled respiration. 2) Methods to quantify respiratory sinus arrhythmia (RSA) index from cardiovascular signals were developed as well: two methods utilizes adaptive filtering and either the measured respiration signal or the ECG-derived respiration signal and one method uses independent component analysis. Developed RSA index methods allow varying respiration rates making them physiologically more accurate than traditional high frequency power with fixed respiration rate, often used as RSA index. 3) Tools for studying the power and the frequency of low frequency (LF) oscillations of cardiovascular signals were developed, including a time-frequency representation for analyzing varying data. An experimental study was conducted with patients of continuum of cardiovascular risks. According to results, aging decreased the frequency of LF oscillation, whereas coronary artery disease decreased it further. 4) Two new ECG-derived respiration (EDR) methods utilizing decomposition techniques were developed. The proposed methods yielded statistically significant improvements over previously developed EDR methods. EDR method enables to get respiratory information from ECG, which in its turn reduces needed modalities in ANS quantification. This thesis provides methods to quantify indexes describing the ANS function more accurately by acknowledging the respiration effects. The results of this thesis may be utilized in various application areas, ranging from clinical to physiology research up to commercial health, wellness and sport products. / Tiivistelmä Autonominen hermosto säätelee tarkasti sydän- ja verenkiertoelimistöä sekä hengitystä. Autonomisen hermoston toimintaa voidaan analysoida laskennallisin menetelmin noninvasiivisesti mitatuista elektrokardiogrammi- (EKG, sydänsähkökäyrä), verenpaine- ja hengityssignaaleista. Useita tekijöitä ja sairauksia voidaan yhdistää autonomisen hermoston epätasapainoon. Väitöskirjassa kehitettiin menetelmiä sydän- ja verisuonijärjestelmän autonomisen säätelyn kuvaamiseksi lyhytaikaisista kardiorespiratorisista tallenteista. Erityistä huomiota on kiinnitetty hengityksen vaikutukseen perinteisiin taajuustasosta laskettaviin muuttujiin, jotka kuvaavat autonomisen hermoston toimintaa. Väitöskirjan päätuloksia ja -tuotoksia ovat: 1) uusi adaptiiviseen suodatukseen pohjautuva laskennallinen menetelmä hengitysvaikutuksien poistamiseksi sydän- ja verisuonisignaaleista. Adaptiivinen suodatin vähensi matalan hengitystaajuuden aiheuttamaa vääristymää hermoston toimintaa kuvaavista parametreistä. Uusi menetelmä mahdollistaa kontrolloimattoman eli vapaan hengitystaajuus-protokollan käytön autonomisen hermoston toiminnan mittauksissa. 2) Uusia menetelmiä respiratorisen sinus arrytmian (RSA) määrittämiseksi sydän- ja verisuonisignaaleista. Kehitetyissä menetelmistä kahdessa käytetään adaptiivista suodatusta hyödyntäen joko mitattua hengityssignaalia tai EKG:stä johdettua hengityssignaalia. Kolmas menetelmä pohjautuu itsenäisten komponenttien analyysiin. Kehitetyt menetelmät RSA:n laskemiseksi sallivat hengitystaajuuden vaihtelun mittauksien aikana, mikä tekee ne fysiologisesti tarkemmaksi kuin perinteisesti käytetty korkeataajuinen (HF) komponentti, joka lasketaan taajuustasossa tietyltä kaistalta riippumatta hengitystaajuudesta. 3) Kehitettiin ja sovellettiin menetelmiä EKG:n ja verenpaineen matalataajuisten (LF) heilahtelujen tutkimista varten. Yhdessä tutkimuksessa sovellettiin aika-taajuustason esitystapaa vaihtelevan datan analysoimiksi. Kokeellinen tutkimus tehtiin aineistolla, joka oli jatkumo sydän- ja verisuonitautien riskejä omaavista potilaista jo sairastuneisiin potilaisiin. Ikääntyminen pienensi matalataajuisen heilahtelun taajuutta ja sepelvaltimosairaus pienensi sitä edelleen. 4) Kaksi uutta hajotelmatekniikoita hyödyntävää menetelmää, joilla lasketaan EKG:stä hengitysvirtausignaali-estimaatti (EDR). Kehitettyjen EDR-menetelmien suorituskyky osoittautui tilastollisesti paremmaksi kuin aikaisemmat menetelmät. Koska hengityssignaali ja -taajuus voidaan johtaa suoraan EKG:stä, tarvittavien mittaussensoreiden määrää vähenee. Lisäksi EDR:ää voidaan hyödyttää autonomisen hermoston toimintaa kuvaavien parametrien estimoinnissa. Väitöskirja tarjoaa menetelmiä autonomisen hermoston toiminnan mittaamiseksi huomioiden erityisesti hengityksen vaikutus estimoitaviin parametreihin. Väitöskirjan tuloksia voidaan soveltaa useissa kardiorespiratorisia signaaleja hyödyntävissä sovelluksissa aina kliinisestä työstä fysiologian tutkimukseen ja kaupallisiin hyvinvointi-, terveys- ja urheilusovelluksiin. / Huomautus/Notice Painetussa virheellinen ISBN: 978-952-62-2312-4, oikea 978-952-62-2310-0. Printed version has incorrect ISBN: 978-952-62-2312-4, it should be 978-952-62-2310-0.

Made available in DSpace on 2016-06-02T20:19:03Z (GMT). No. of bitstreams: 1 1052.pdf: 1426257 bytes, checksum: 302057355291e83990486aed5f396a65 (MD5) Previous issue date: 2004-12-22 / Universidade Federal de Minas Gerais / The purpose of the present study was to evaluate the effects of the aging and the regular physical activity on the autonomic control of heart rate (HR) at rest and during deep breath test (DBT) in healthy men. Nine young sedentary (mean = 22.67 ±2.45 years), sixteen young active (mean = 22.38 ±2.13 years), eight sedentary older (mean = 63.5 ±2.39 years) and eight older active (mean = 61 ±1.6 years) men were studied. Electrocardiogram was continuously recorded during 15 minutes (rest), 4 minutes (DBT, with breath rate at 5 to 6 cycles/minute) and 1 minute (recovery) in supine position. The HR (bpm) and the R-R intervals (RRi) (ms) were analyzed by time (RMSSD index) and frequency domain methods. The power spectral components were expressed as absolute (a) and normalized units (nu) at low (LF) and high (HF), and as the LF/HF. The HR and the RRi were analyzed by the respiratory sinus arrhythmia (RSA) indices: expiration/inspiration ratio (E/I) and inspiration-expiration difference (&#8710;IE). The HR was lower in the activity groups than to the matched-age sedentary groups. The older sedentary group had lower heart rate variability (HRV), E/I and &#8710;IE than young ones. The older active group showed higher RMSSD and HF component than matched-age sedentary group (45.04 and 28.78 ms, 58,167 and 12,218 ms2/Hz, P<0.05; respectively). No differences were found between young and older active groups for RMSSD (61.71 and 45.04 ms, respectively) and HRV (TP:130,816 and 125,710, LFa:33,295 and 32,611, HFa:84,346 and 58,167, ms2/Hz, respectively) and DBT indices (E/I: 1.40 and 1.35, &#8710;IE: 23 and 18, respectively). The results show that aging associates with inactivity reduces the HRV. However, the regular physical activity increases the HRV, independent of age, suggesting attenuation the effects of the aging in the autonomic control of the heart rate. / O presente estudo teve como objetivo avaliar os efeitos da idade e da atividade física regular sobre o controle autonômico da freqüência cardíaca (FC) durante o repouso e durante a manobra para acentuar a arritmia sinusal respiratória (MASR) em homens saudáveis. Participaram do presente estudo, 9 jovens sedentários (média= 22,67 ±2,45 anos), 16 jovens ativos (média= 22,38 ±2,13 anos), 8 idosos sedentários (média= 63,5 ±2,39 anos) e 8 idosos ativos (média= 61 ±1,6 anos). O traçado eletrocardiográfico foi registrado durante 15 minutos (repouso com respiração espontânea), 4 minutos (MASR, com freqüência respiratória mantida entre 5 a 6 ciclos/minuto) e 1 minuto de recuperação. A freqüência cardíaca (FC), em bpm, e os intervalos RR (iR-R), em ms, foram analisados pelo domínio do tempo (índice RMSSD) e pelo domínio da freqüência. Os componentes da potência espectral foram expressos em valores absolutos (a) e em unidades normalizadas (un) para a densidade total de potência (DTP), as bandas de baixa freqüência (BF), alta freqüência (AF) e razão BF/AF. A FC obtida durante a manobra MASR foi analisada a partir dos índices: razão expiração/inspiração dos iR-R (E/I) e de sua variação durante a inspiração-expiração (&#8710;IE). Os grupos ativos apresentaram valores inferiores de FC de repouso em comparação aos controles sedentários de mesma idade. O grupo idoso sedentário apresentou menor variabilidade da variabilidade da freqüência cardíaca (VFC), E/I e &#8710;IE que o grupo jovem sedentário. O grupo idoso ativo mostrou valores superiores de RMSSD e da banda de HF em relação ao grupo sedentário idoso (45,04 e 28,78 ms, 58.167 e 12.218 ms2/Hz, p<0,05; respectivamente). Diferenças estatísticas não foram encontradas entre o grupo jovem ativo e idoso ativo para o RMSSD (61,71 e 45,04 ms, respectivamente) e para a VFC (DTP: 130.816 e 125.710, LFa: 33.295 e 32.611, HFa: 84.346 e 58.167, ms2/Hz, respectivamente) e para os índices da ASR (E/I: 1,40 e 1,35, &#8710;IE: 23 e 18, respectivamente). Para os grupos sedentários foi observado correlação negativa entre os índices DTP, AFa, E/I e &#8710;IE e a idade (p<0,05), sendo que o mesmo não pode ser observado nos grupos ativos. Os resultados sugerem que o envelhecimento associado ao sedentarismo provoca reduções na VFC, representadas pela diminuição da atividade vagal sobre o coração, determinada tanto pela análise no domínio da freqüência como pelos índices da arritmia sinusal respiratória. Entretanto, a atividade física regular aumenta a VFC, independentemente da idade, e atenua as alterações, decorrentes do processo de envelhecimento, no controle autonômico da freqüência cardíaca.

Made available in DSpace on 2016-06-02T20:19:28Z (GMT). No. of bitstreams: 1 DissMDBS.pdf: 1917686 bytes, checksum: 9d2cd0affae35c5474a851d16fe9b2e0 (MD5) Previous issue date: 2006-03-23 / Universidade Federal de Minas Gerais / The purpose of the present study was to evaluate the effects of physiotherapeutic intervention on the autonomic control of heart rate through heart rate variability (HRV) indices at rest (supine and seated positions), during deep breath test (DBT), during an exercise protocol and during walking, in patients with acute myocardial infarction (AMI) submitted to phase I of cardiac rehabilitation. Second, evaluate the effects of an inspiratory muscle training (IMT) on the maximal inspiratory pressure (PImax) and on the magnitude of respiratory sinus arrhythmia (RSA). Initially, thirty five patients of both genders were studied in the 1st stage of the cardiovascular physiotherapy (CPT), however, only eighteen of them performed all six stages of treatment (mean = 56± 13 year). These patients, who were admitted to the Coronary Care Unit (CCU) (two days) and the ward (four days) of the Santa Casa de Misericórdia de São Carlos with noncomplicated AMI, were hemodynamically stable and used conventional medications. The 1st stage was initiated 22± 5 hours after the CCU admission and the progression to other 5 stages was done based in the daily clinical evolution of each patient. This stage included 10 minutes of rest (pre and post-exercise protocol), 4 minutes of deep breathing test and 5 minutes of exercise protocol (active-assisted low extremities exercises) in the supine position. Furthermore, the 6th stage included 10 minutes of rest in the supine position (pre and post-intervention), 4 minutes of deep breathing test, 5 minutes of rest in the seated position (pre and post-intervention), 5 minutes of active low extremities exercises in the orthostatic position and 15 minutes of walking. The instantaneous heart rate (HR) and the R-R interval (RRi) were acquired by a HR monitor (Polar S810) during all stage and the blood pressure (BP) was measured before and after each stage. Additionally, the PImax was measured (in the seated position) through a manuvacuometer at the pre and post-IMT, which was performed at the 2nd to 6th stages. The intensity of IMT was settled at 40% of PImax pressure load. The HRV was analyzed by time (RMSSD and RMSM indices) and frequency (Fast Fourier Transform) domain methods. The power spectral density was expressed as normalized units (nu) at low (LF) and high (HF) frequencies, and as the LF/HF. Results: The cumulative effect of physiotherapeutic intervention caused increase of AFnu (p<0.05) and decrease of LFnu (p<0.05) when they were evaluated at the rest pre-intervention in the supine position and during exercise protocol of 1st and 6th stages. Additionally, decreased LF/HF was also observed at rest pre-intervention in the supine position. However, no changes were observed for these indices when the 1st and 6th stages were compared to during the RSA, in the rest post-intervention (supine position) and in the rest pre and post-intervention (seated position), and the 4th and 6th stages were compared to during the walking. In the time domain, RMSM and RMSSD diminished at 1st to 6th stages for rest post-intervention in supine position. The IMT augmented the PImax in 46% (P<0.05), but increased PImax and the RSA magnitude did not correlate among them. Conclusion: The CPT realized in the phase I of the cardiac rehabilitation caused increase in the vagal activity and decrease the sympathetic activity during rest and exercises conditions, since the beta-blockade and IECA medications dosages were not altered. Additionally, the intensity used in the IMT was able to improve the PImax, but it did not influence on the RSA magnitude. Financial support: FAPESP (04/05788-6) and CNPq (478799/2003-9). / O presente estudo teve como principal objetivo avaliar a modulação do sistema nervoso autônomo no coração, por meio do comportamento da variabilidade da freqüência cardíaca (VFC) em repouso, supino e sentado, durante manobra para acentuar a arritmia sinusal respiratória (ASR), exercício e deambulação em pacientes com infarto agudo do miocárdio (IAM) antes e após serem submetidos à fisioterapia: fase I da reabilitação cardiovascular. Como objetivo secundário foi avaliada a pressão inspiratória máxima (PImáx) antes e após um programa de treinamento muscular inspiratório (TMI), bem como, a influência do TMI na magnitude da ASR. Foram estudados 35 pacientes na 1ª etapa (controle) e 18 antes e após a fisioterapia cardiovascular (FTCV), com idade média de 56±13 anos, de ambos os sexos, internados na Unidade Coronariana (UCO) (2 dias) e enfermaria da Irmandade Santa Casa de Misericórdia de São Carlos (4 dias) com IAM não complicado. Todos estavam hemodinamicamente estáveis e em uso de medicações convencionais. Foram submetidos a 1ª etapa após 22±5 horas da chegada na UCO e progrediram na FTCV até a 6ª etapa, diariamente, baseado na evolução clínica. A 1ª etapa foi composta de 10 minutos (min) de repouso supino pré (R1) e pós-intervenção (R2), 4 min da manobra para acentuar a ASR (MASR) e 5 min de exercícios ativos-assistidos de membros inferiores (MMII) na postura supina. Já a 6ª etapa foi composta de 10 min de R1 e R2, 4 min da MASR, 5 min de repouso sentado pré (RS1) e pós-intervenção (RS2), 5 min de exercícios ativos de MMII na postura em pé e 15 min de deambulação. Os intervalos R-R (iRR) e a freqüência cardíaca (FC) foram obtidos, batimento a batimento, pelo freqüencímetro Polar® S810i e a pressão arterial (PA) foi aferida antes, durante e após a FTCV. A medida da PImáx foi realizada com um manovacuômetro, na posição sentada, na 2ª etapa e reavaliada na 6ª etapa. O TMI foi realizado, na posição sentada, da 2ª até a 6ª etapa, sendo que a carga pressórica foi de 40% da PImáx obtida na 2ª etapa. A VFC foi analisada nos domínios do tempo (DT - índices RMSSD e RMSM dos iRR em ms) e da freqüência (DF por meio da análise espectral), a qual forneceu as bandas de baixa freqüência (BF) e alta freqüência (AF), expressas em unidades normalizadas (un), e a razão BF/AF. Resultados: Com relação ao efeito cumulativo das seis etapas da FTCV, no DF, houve diminuição da BFun e aumento da AFun no R1 e durante o exercício e diminuição da razão BF/AF no R1 da 1ª para a 6ª etapa, não havendo alterações destas variáveis durante a MASR e no R2 da 1ª para a 6ª etapa, no RS1 e RS2 da 2ª para 6ª etapa e durante a deambulação da 4ª para 6ª etapa. No DT, os índices RMSSD e RMSM diminuíram no R2 da 1ª para a 6ª etapa. Houve aumento de 46% da PImáx com o TMI (p<0,05) e não houve correlação entre o aumento da PImáx e a magnitude de resposta da ASR. Conclusões: A FTCV fase I aplicada aos pacientes com IAM promoveu aumento da atuação vagal e redução da atuação simpática tanto na condição de repouso supino como durante a execução de exercício, uma vez que a dosagem das medicações betabloqueadores e inibidoras da enzima conversora de angiotensina permaneceram inalteradas durante o estudo. Ainda, o TMI promoveu aumento da PImáx na intensidade aplicada, no entanto, não influenciou a magnitude de resposta da ASR Suporte Financeiro: FAPESP Proc. 04/05788- 6, CNPq Proc. 478799/2003-9.

Made available in DSpace on 2016-06-02T20:18:10Z (GMT). No. of bitstreams: 1 2010.pdf: 2854762 bytes, checksum: b0421ce836a4726be750d7bf5a373fb9 (MD5) Previous issue date: 2008-08-18 / Universidade Federal de Sao Carlos / The ageing process is known to affect different tissues and systems. It is well-established that age-associated changes in cardiovascular structure and function are related to the risk of cardiovascular diseases. Because of the vast amount of cardiovascular modifications observed with ageing, the present study focused on three important topics: heart rate variability (HRV), blood pressure variability (BPV) and endothelial dysfunction. Furthermore, we also investigated the effects of physical activity (endurance and strength) on the autonomic control of heart rate (HR), which might be used as non-pharmacological therapy. Thirty five young subject between 18 and 30 years old (14 sedentary men, 5 sedentary women and 16 active men) and thirty eight middleaged/older subjects between 55 and 70 years old (16 sedentary men, 14 sedentary women and 8 active men) were studied. In addition, the subjects are distributed among 3 different studies. In the first one, the effects of the ageing process and active life-style on the autonomic control of HR were investigated in young and middleaged/older subjects. Electrocardiogram was recorded during 15 minutes of rest and 4 minutes of controlled breathing (5 to 6 cycles/min) in the supine position. HR and RR intervals were analyzed by time and frequency domain methods. The active groups presented lower HR and higher HRV (time domain) than the sedentary groups, whereas both middle-aged/older groups showed lower HRV (frequency domain). Additionally, interaction between ageing and life-style effects was observed for respiratory sinus arrhythmia (ASR) indexes (calculated during the controlled breathing test). The sedentary middle-aged/older group presented lower ASR magnitude than the other groups studied. The results suggest that ageing reduces HRV, however, regular physical activity improves vagal modulation on the heart and, consequently, attenuates the effects of ageing on the autonomic control of HR. In the second study, we aimed to investigate if strength training is able to improve cardiac autonomic control in healthy middle-aged/older men. HRV was evaluated before and after 12 weeks of isokinetic eccentric strength training (2days/week, 2-4 sets of 8-12 repetitions at 75-80% peak torque), involving knee flexion and extension. Strength training decreased the systolic blood pressure and increased the torque. However, an autonomic imbalance towards sympathetic modulation predominance was induced by an unknown mechanism. In the third study, we evaluated the effect of ageing on the BPV and endothelial function. We also sought for correlations between increased BPV and impaired endothelium dependent-dilation (EDD) in the middle-aged/older group. Intra-brachial artery BPV and conduit vessel EDD (brachial artery flow-mediated dilation, FMD) were determined in healthy young and middle-aged/older subjects. Moreover, endothelial function of resistance vessels was evaluated by venous occlusion plethysmoghaphy in the middle-aged/older group. The young group presented lower systemic oxidative stress, lower systolic BPV and higher FMD compared with the middle-aged/older group. After split this group according to the BPV, lower FMD was observed in the middleaged/older group with higher BPV. In addition, FMD was inversely correlated to BPV. The lower BPV group showed a great reduction (55%) in the forearm blood flow responses when NG-monometyl-L-arginine (nitric oxide inhibitor) was co-infused with acetylcholine (vs 14% in the higher BPV group). The results suggest that ageing process increases BPV and reduces endothelial function. Additionally, middle-aged/older subjects with higher BPV also have impaired EDD compared with their peers with lower BPV. General Conclusions: the results from the studies described above suggest that ageing process causes decrease of HRV, increase of BPV and decrease of endothelial function. Moreover, aerobic exercise has a cardioprotector effect, since it was able to attenuate the ageing effects on the cardiac vagal modulation. This same benefit, however, was not observed after 12 weeks of eccentric strength training. On the other hand, the strength training program performed by healthy older subjects modified the sympato-vagal balance toward the sympathetic modulation. Finally, systolic BPV oscillations seem to have a narrow relationship with vasodilation mediated by nitric oxide. Then, more studies are needed to clarify the cause-effect relation between those important variables. / O envelhecimento é um processo complexo que causa alterações em vários sistemas do organismo. Em relação ao sistema cardiovascular, modificações na sua estrutura e função estão diretamente relacionadas com o risco aumentado de desenvolvimento de doenças cardiovasculares em idosos. Dentre as diversas alterações cardiovasculares observadas com o envelhecimento, apenas as relacionadas à variabilidade da freqüência cardíaca (VFC), variabilidade da pressão arterial (VPA) e disfunção endotelial foram abordadas no presente estudo. Além disso, foram também investigados os efeitos de dois tipos distintos de exercício físico, ou seja, de resistência aeróbia e de força muscular, sobre o controle autonômico da freqüência cardíaca (FC) de sujeitos saudáveis, como uma forma alternativa de terapia não-farmacológica. Participaram do presente estudo: 35 sujeitos jovens na faixa etária de 18 a 30 anos (14 homens sedentários, 5 mulheres sedentárias e 16 homens ativos) e 38 sujeitos meia-idade/idosos na faixa etária de 55 a 70 anos (16 homens sedentários, 14 mulheres sedentárias e 8 idosos ativos), os quais estão distribuídos em 3 estudos distintos. No primeiro estudo, os efeitos do envelhecimento e do estilo de vida sobre o controle autonômico da FC foram investigados em jovens e meiaidade/idosos com padrão de vida sedentário ou ativo. O sinal eletrocardiográfico foi obtido durante 15 minutos de repouso e 4 minutos de respiração controlada (5-6 ciclos/min), ambos na posição supina. A FC e os intervalos RR foram analisados no domínio do tempo e da freqüência. Adicionalmente, os índices da arritmia sinusal respiratória (ASR) também foram calculados. Os grupos ativos apresentaram menor FC e maior VFC (domínio do tempo) em relação aos grupos sedentários, enquanto que ambos os grupos idosos apresentaram menor VFC (domínio da freqüência). Além disso, foi observado interação entre idade e estilo de vida, já que a magnitude da ASR foi menor no grupo meia-idade/idoso sedentário comparativamente aos demais grupos. Os resultados indicam que a VFC reduz com o aumento da idade. Entretanto, a atividade física regular produz efeitos positivos sobre a modulação vagal cardíaca e, conseqüentemente, atenua os efeitos do envelhecimento sobre o controle autonômico da FC. No segundo estudo, foi avaliado se o treinamento de força excêntrica é capaz de modificar o controle autonômico da FC de idosos saudáveis. A VFC foi avaliada, durante o repouso supino e sentado, após 12 semanas de treinamento de força isocinética excêntrica (extensão e flexão do joelho, 2 dias/semana, 2-4 séries de 8-12 repetições, 75-80% do pico de torque). O treinamento de força foi capaz de aumentar o torque muscular e reduzir a pressão arterial (PA) sistólica de idosos saudáveis. Entretanto, o mesmo causou um desbalanço simpato-vagal, em direção a predominância simpática, o qual foi produzido por mecanismos desconhecidos. No terceiro estudo, foi avaliado se a VPA está aumentada com o avançar da idade e, ainda, se a mesma tem alguma relação com reduções na vasodilatação endotélio-dependente (VED) em sujeitos meiaidade/idosos saudáveis. A VPA intra-arterial e a VED (dilatação mediada por fluxo, DMF) da artéria braquial (i.e., vaso de condutância) foram avaliadas em sujeitos jovens e meia-idade/idosos de ambos os sexos. Adicionalmente, o grupo meia-idade/idoso também foi submetido à pletismografia de oclusão venosa para avaliar a função endotelial dos vasos de resistência. Os jovens apresentaram menor estresse oxidativo sistêmico, menor VPA sistólica e maior DMF, comparativamente ao grupo meia-idade/idoso. Quando esse grupo foi dividido de acordo com a VPA, observou-se DMF reduzida no grupo com alta VPA. Adicionalmente, a DMF mostrou correlação inversa com a VPA. Em relação aos vasos de resistência, o grupo com baixa VPA mostrou redução de 55% na resposta do fluxo sangüíneo quando NG-monometil-L-arginina (inibidor da produção de óxido nítrico) foi co-infudido com acetilcolina (vs 14% no grupo com alta VPA). Os resultados indicam que o envelhecimento causa redução da função endotelial e aumento da VPA. Além disso, sujeitos meia-idade/idosos com alta VPA apresentam DMF reduzida quando comparados aos seus pares com baixa VPA. Conclusão geral: os resultados obtidos nos três estudos sugerem que o envelhecimento causa redução na VFC, aumento da VPA e redução da função endotelial. Além disso, a atividade física aeróbia possui um efeito cardioprotetor, já que essa foi capaz de atenuar os efeitos do envelhecimento sobre a modulação vagal cardíaca. Entretanto, esses efeitos benéficos não foram observados com o treinamento de força excêntrica, pois 12 semanas de treinamento alteraram o balanço simpato-vagal em direção a modulação simpática. Por fim, o aumento nas oscilações da PA sistólica mostrou uma estreita relação com a vasodilatação mediada pelo óxido nítrico, a qual necessita de maiores investigações no sentido de determinar a relação de causa e efeito entre essas duas importantes variáveis.

The present study examined the ability of a Virtual Reality (VR) public speaking task to elicit physiological arousal in adults with SAD (n=25) and Controls (n=25). A behavioral assessment paradigm was employed to address three study objectives: (a) to determine whether the VR task can elicit significant increases in physiological response over baseline resting conditions (b) to determine if individuals with SAD have a greater increase from baseline levels of physiological and self-reported arousal during the in vivo speech task as opposed to the VR speech task and (c) to determine whether individuals with SAD experience greater changes in physiological and selfreported arousal during each speech task compared to controls. Results demonstrated that the VR task was able to elicit significant increases in heart rate, skin conductance, and respiratory sinus arrhythmia, but did not elicit as much physiological or self-reported arousal as the in vivo speech task. In addition, no differences were found between groups. Clinical implications of these findings are discussed

<p>The last two decades have shown a boom in the field of wearable sensing technology. Particularly in the consumer industry, growing trends towards personalized health have pushed new devices to report many vital signs, with a demand for high accuracy and reliability. The most common technique used to gather these vitals is photoplethysmography or PPG. PPG devices are ideal for wearable applications as they are simple, power-efficient, and can be implemented on almost any area of the body. Traditionally PPGs were utilized for capturing just heart rate, however, recent advancements in hardware and digital processing have led to other metrics including respiratory rate (RR) and peripheral oxygen saturation (SpO2), to be reported as well. Our research investigates the potential for wearable devices to be used for outpatient apnea monitoring, and particularly the ability to detect opioid misuse resulting in respiratory depression. Ultimately, the long-term goal of this work is to develop a wearable device that can be used in the rehabilitation process to ensure both accountability and safety of the wearer. This document details contributions towards this goal through the design, development, and evaluation of a device called “Kick Ring”. Primarily, we investigate the ability of Kick Ring to record heartrate (HR), RR, and SpO2. Moreover, we show that the device can calculate RR in real time and can provide an immediate indication of abnormal events such as respiratory depression. Finally, we explore a novel method for reporting apnea events through the use of several PPG characteristics. Kick Ring reliably gathers respiratory metrics and offers a combination of features that does not exist in the current wearables space. These advancements will help to move the field forward, and eventually aid in early detection of life-threatening events.</p>