Since blood pressure is a significant parameter to examine people's physical attributes and it is useful to indicate cardiovascular diseases, the measurement/estimation of blood pressure has gained increasing attention. The continuous, cuff-less and non-invasive blood pressure estimation is required for the daily health monitoring. In recent years, studies have been focusing on the ways of blood pressure estimation based on other physiological parameters. It is widely accepted that the pulse transit time (PTT) is related to arterial stiffness, and can be used to estimate blood pressure.<p> A promising signal processing technology, Hilbert-Huang Transform (HHT), is introduced to analyze both ECG and PPG data, which are applied to calculate PTT. The relationship between blood pressure and PTT is illustrated, and the problems of calibration and re-calibration are also discussed. The proposed algorithm is tested based on the continuous data from MIMIC database. To verify the algorithm, the HHT algorithm is compared with other used processing technique (wavelet transform). The accuracy is calculated to validate the method. Furthermore, we collect data using our own developed system and test our algorithm.

The purpose of this investigation was to quantify the acute pressor response to caffeine at rest and during exercise, and to compare responses for different reportings of caffeine consumption and sensitivity. Eight young men with high use (HU) consumption patterns (<600 mg/day) and eight with low use (LU) patterns (<90 mg/day) participated. Caffeine (C) (4.5 mg/kg fat free mass) and placebo (P) were administered, double-blind and counterbalanced. Systolic (SBP), diastolic blood pressure (DBP) and heart rate (HR) were monitored during baseline, 40 minutes of absorption and graded treadmill walking. Oxygen consumption (V02) and rating of perceived exertion (RPE) were monitored during exercise. No significant differences were found for the responses to C between HU and LU nor between sensitive and not sensitive groups. Following a 12 hour abstinence, caffeine significantly increase SBP and DBP at absorption compared to P (11/9 mm Hg). The increase was additive with exercise for SBP but not DBP. Caffeine significantly increased VO2 compared to P. No significant differences were found for HR nor RPE between C and P trials. The present data indicate chronic caffeine consumption does not build tolerance to the acute pressor response to caffeine ingestion, the resting pressor response is additive with the pressor response to exercise for SBP, and individual perceptions of caffeine sensitivity are not accurate predictors of pressor responses. / School of Physical Education

Our study investigated the potential for a combination of diabetes and nicotine treatment to affect blood pressure in the rat. We used streptozotocin injection and oral nicotine feeding as models of type-1 diabetes and smoking respectively. Blood pressure was assessed using the indirect tail-cuff technique. In an attempt to further characterize our experimental model, we also observed body weight, plasma glucose and the contractility of aortic segments in various treatment groups. Our data was expressed as mean ± SEM, and significance was regarded as P < 0.05. We found that a combination of streptozotocin and nicotine treatment resulted in a significant elevation of systolic blood pressure compared with either treatment alone, or control. Furthermore, assessment of aortic contractility showed alteration of reactivity to both phenylephrine and sodium nitroprusside as a result of the combination treatment. We also observed a trend for our combination treatment to exacerbate the elevation of plasma glucose level seen in streptozotocin induced diabetic rat models. This study serves as an experimental basis to underline the importance of cessation of tobacco use for individuals with diabetes mellitus.

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Thesis (M.S.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains v, 84 p. : ill. Vita. Includes abstract. Includes bibliographical references (p. 43-47).

Purpose: Cardiovascular events and complications are the major causes of death in patients with end-stage renal disease (ESRD)¹⁻³. Antihypertensive agents that block the renin-angiotensin-aldosterone system (RAAS) are considered first-line therapy in patients with ESRD as these patients have a propensity for RAAS overactivation⁴⁻⁷. Studies show that aldosterone receptor blockade reduces BP in patients with chronic kidney disease (CKD) and helps prevent negative outcomes from continued renal cellular damage⁸⁻¹⁰. Spironolactone, an aldosterone antagonist, has the potential to provoke hyperkalemia. Consequently, current guidelines do not recommend spironolactone to manage hypertension in ESRD because of this risk⁶⁻⁷. Our primary objectives were to determine the change in BP and serum potassium levels following spironolactone use. Methods: This study was a retrospective, pre-post cohort study in ESRD patients with difficult-to-control BP receiving HD. Patients prescribed spironolactone (25 mg to 50 mg) between January 2009 and January 2013 were identified using an e-prescribing record from three HD clinics in San Antonio, TX. Patients were included if they were prescribed spironolactone as 'add-on' therapy to control BP for at least 8 weeks. Results: Seventy patients were evaluated and the majority of them were overweight, diabetic, Hispanic females with a mean 65 years of age. Mean SBP and DBP decreased from baseline to week 8 [-20.74 mmHg (p < 0.0001) and -9.7 mmHg (p < 0.0426), respectively]. Mean serum potassium levels increased by an average of 0.18 mEq/L (4.5 mEq/L to 4.68 mEq/L, p = 0.09). Data analysis revealed that only 9 of 70 patients had a serum potassium level > 5.5 mEq/L at week 8. There were no adverse cardiac events reported as a result of these potassium concentrations. A two-fold decrease in SBP was seen in patients with a body mass index (BMI) > 25 kg/m² compared to patients with a BMI of ≤ 25 kg/m². At the end of the study, 23 patients (33%) achieved the goal BP for healthy adults of < 140/90 mmHg. Conclusion: These findings demonstrated that using spironolactone use in ESRD patients receiving HD can be effective and safe. / text

While it is now understood that long-standing hypertension is predictive of later cognitive decline and risk for dementia, little research attention to date has focused on whether the short-term dynamics of blood pressure exert immediate influence on cognitive functioning. The present study contributes to this growing field with a conceptual replication and extension of work by Gamaldo, Weatherbee and Allaire (2008). A sample of 27 older adults (M=70.2 years) completed daily assessments of blood pressure, psychological stress and cognitive functioning for 14 consecutive days. Multilevel models conditional on demographic factors were applied to simultaneously estimate between- and within-person effects across three metrics of blood pressure (systolic, diastolic and pulse pressure) and five measures of cognitive functioning. To follow a suggestion proposed by Gamaldo et al., the model was extended to include main effect and blood pressure interaction terms for stress at both levels. In secondary analyses, within-person mediation models were applied to explore blood pressure as a mediator between stress and cognition. Results from the first model demonstrated a direct, positive association between occasion diastolic pressure and episodic memory. A cross-level interaction term revealed that processing speed was impaired on high-diastolic pressure days for those with high diastolic pressure on average. We found no evidence that occasion blood pressure mediated the association between stress and cognition. Overall, our results align with the hypothesis that age-related changes to vascular structures impair the carrying capacity of blood vessels and that occasions of increased blood pressure provide additional force to overcome these limitations, delivering larger quantities of blood and oxygen to cerebral tissue. We conclude that upward fluctuations in diastolic pressure may be cognitively beneficial for older adults; diastolic pressure is the most sensitive metric for detection of within-person associations with cognition; and episodic memory and processing speed exhibit sensitivity to occasion blood pressure levels. / Graduate

Strong evidence has linked dietary sodium intake to blood pressure, but the effects of sodium intake on cardiovascular diseases (CVD) outcomes remain elusive, especially for older population. We examined the association between estimated usual sodium intake and CVD and all-cause mortality in a nationally representative sample of 4068 US adults aged 51 and older surveyed in 1988-1994. After a mean follow-up of 12.9 years from 1988 to 2006, 1680 participants died: 734 from CVD; 392 from ischemic heart disease (IHD); and 144 from stroke. In the Cox proportional models adjusted for sociodemographic variables and CVD risk factors, sodium intake was not significantly associated with all-cause, CVD, IHD and stroke mortality. No significant interactions were observed between sodium intake and sex, race/ethnicity, hypertension status, body mass index or physical activity for any of the outcomes studied. However, among Mexican-Americans sodium intake was significantly and linearly associated with CVD mortality.

The primary purpose of the present study was to determine the acute hemodynamic responses to twenty-three select yoga postures in advanced and novice yoga practitioners. Additionally, we sought to determine if trunk flexibility is related to arterial stiffness. Using a cross-sectional study design, 37 apparently healthy adults (26 females and 11 males; 22-71 years old) were divided into two groups according to level of yoga experience. Beat-to-beat measures of blood pressure, stroke volume, cardiac work-load, cardiac output, and total peripheral resistance were measured using a finger plethysmograph during the yoga routine. Baseline measures of trunk flexibility (sit-and-reach scores and inclinometer measurements) and arterial stiffness (carotid-femoral pulse wave velocity) were also compared. Yoga postures elicited significant increases in heart rate, blood pressure and cardiac output (P<0.05) for both groups. There was no difference in blood pressure responses between the two groups throughout the yoga testing session. Lumbar flexion, as measured by an inclinometer, was significantly (P<0.01) and inversely associated with cfPWV (r=-0.52). / text

Obstructive sleep apnea (OSA) is a disease characterized by nighttime airflow limitation, hypoxemia, arousal from sleep, and elevated sympathetic activity and blood pressure. With time, this nighttime dysfunction gives rise to daytime hypertension and a heightened risk for cardiovascular disease. Current treatment options for OSA are not always effective for all patients and the gold-standard intervention, continuous positive airway pressure, has discouraging compliance rates. The work set forth in this dissertation has as its focus a novel intervention for sleep apnea known as inspiratory muscle training (IMT). IMT improves respiratory function and cardiovascular health but has not been implemented previously as a treatment for OSA. As such, Study 1 implements IMT in individuals with mild and moderate OSA, with the objective of assessing the effects of training on the cardio- respiratory parameters of this disease. We randomly assigned 24 individuals with mild- moderate OSA into one of two groups: training vs. placebo, to assess the effects of 6 weeks of training on overnight polysomnography, subjective sleep quality, blood pressure, circulating inflammatory T cells, and plasma catecholamine content. Our results show IMT- related improvements in sleep quality, reduction in the number of arousals from sleep and in periodic limb movements following 6 weeks of training. Most important, IMT was associated with a significant reduction in systolic (~12 mmHg) and diastolic (~5 mmHg) blood pressure, relative to sleep apneics who undertook 6 weeks of placebo training. Additionally, individuals in the training group exhibited ~30% lower levels of sympathetic activity, as measured by plasma catecholamines, relative to placebo trained peers. The mechanism(s) that underlie the IMT-related reductions in blood pressure and sympathetic activity remain to be determined. However, in an effort to determine the precise respiratory stimulus that contributes to the results obtained in Study 1, we subsequently assessed the specific respiratory components of IMT to determine which component (large intrathoracic pressures and/or large lung volumes) likely contributes to the reduction in blood pressure in Study 1. The results of this study conducted in normotensive adults show that respiratory training that entails either large negative or positive intrathoracic pressures reduces systolic and diastolic blood pressure in healthy young adults. Importantly, neither the generation of large lung volumes alone nor performance of daily paced breathing is sufficient to lower blood pressure. Study 3 is a methodologic study that has as its focus upper airway electromyography (EMG) and the utility of assessing EMG activity across a range of conditions and breathing tasks in wakefulness. Because OSA traditionally has been viewed as the result of neuromuscular dysfunction of the upper airway that occurs during sleep, the aim of this work was to develop a "fingerprint" of healthy electromyographic activities during the day in healthy adults across a range of breathing tasks, body positions, and from two different muscle compartments of the upper airway. The findings from this study demonstrate regional differences in muscle activity that vary as a function of body position and task. These data from healthy subjects provide the basis of comparison for subsequent studies in individuals with obstructive sleep apnea.