Michael H. Smolensky's research while affiliated with University of Texas at Austin and other places

Publications (335)

Article
Atherosclerosis, a chronic inflammatory disease of the arteries that appears to have been as prevalent in ancient as in modern civilizations, is predisposing to life-threatening and life-ending cardiac and vascular complications, such as myocardial and cerebral infarctions. The pathogenesis of atherosclerosis involves intima plaque buildup caused b...
Article
The pharmacodynamics of hypertension medications can be significantly affected by circadian rhythms in the biological mechanisms of the 24 h blood pressure (BP) pattern. Hypertension guidelines fail to recommend the time of day when patients, including those who require treatment with multiple medications, are to ingest BP-lowering therapy. We cond...
Article
Sudden cardiac death (SCD), the unexpected death due to acquired or genetic cardiovascular disease, follows distinct 24-hour patterns in occurrence. These 24-hour patterns likely reflect daily changes in arrhythmogenic triggers and the myocardial substrate caused by day/night rhythms in behavior, the environment, and endogenous circadian mechanisms...
Article
Sudden cardiac death (SCD) is the sudden, unexpected death due to abrupt loss of heart function secondary to cardiovascular disease. In certain populations living with cardiovascular disease, SCD follows a distinct 24-hour pattern in occurrence, suggesting day/night rhythms in behavior, the environment, and endogenous circadian rhythms result in da...
Article
Borbély proposed an interacting two-component model of sleep regulation comprising a homeostatic Process S and a circadian Process C. The model has provided understanding of the association between core body temperature (CBT) as a key element of Process C that is deterministic of sleep onset and offset. However, it additionally provides a new persp...
Article
Several prospective studies consistently report elevated asleep blood pressure (BP) and blunted sleep-time relative systolic BP (SBP) decline (non-dipping) are jointly the most significant prognostic markers of cardiovascular disease (CVD) risk, including heart failure (HF); therefore, they, rather than office BP measurements (OBPM) and ambulatory...
Article
The pharmacokinetics (PK) – absorption, distribution, metabolism, and elimination – and pharmacodynamics (PD) of hypertension medications can be significantly affected by circadian rhythms. As a consequence, the time when blood pressure (BP) lowering medications are ingested, with reference to the staging of all involved circadian rhythms modulatin...
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This article summarizes the current literature and documents new evidence concerning drug-drug interactions (DDI) stemming from pharmacogenomic and circadian rhythm determinants of therapies used to treat common cardiovascular diseases (CVD), such as atherosclerosis and hypertension. Patients with CVD often have more than one pathophysiologic condi...
Article
Circadian rhythms impact cardiac and vascular pathophysiology, resulting in 24-hour patterning of symptoms and life-threatening/ending events (chronopathology), plus kinetics and dynamics of medications (chronopharmacology), resulting in administration-time differences in efficacy and safety. Scheduling medications according to circadian rhythm det...
Article
Combined evidence of published prospective outcome trials and meta-analyses substantiate elevated asleep blood pressure (BP) and blunted sleep-time relative BP decline (non-dipping), regardless of wake-time office BP and awake or 24h BP means, are jointly the most highly significant independent prognostic markers of cardiovascular disease (CVD) ris...
Article
Pharmacokinetics of hypertension medications is significantly affected by circadian rhythms that influence absorption, distribution, metabolism and elimination. Furthermore, their pharmacodynamics is affected by ingestion-time differences in kinetics and circadian rhythms comprising the biological mechanism of the 24 h blood pressure (BP) pattern....
Article
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Background: Performance of wrist actigraphy in assessing sleep not only depends on the sensor technology of the actigraph hardware but also on the attributes of the interpretative algorithm (IA). The objective of our research was to improve assessment of sleep quality, relative to existing IAs, through development of a novel IA using deep learning...
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Current hypertension guidelines fail to provide a recommendation on when-to-treat, thus disregarding relevant circadian rhythms that regulate blood pressure (BP) level and 24 h patterning and medication pharmacokinetics and pharmacodynamics. The ideal purpose of ingestion-time (chronopharmacology, i.e. biological rhythm-dependent effects on the kin...
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Resumen Introducción y objetivos La presión arterial (PA) ambulatoria predice el riesgo de enfermedad cardiovascular (ECV) mejor que las mediciones clínicas (MCPA). Sin embargo, los modelos actuales de estratificación del riesgo de ECV se basan exclusivamente en las MCPA junto con otros factores tradicionales, como edad, sexo, tabaquismo, dislipem...
Article
Introduction: Hypertension guidelines do not recommend the time to administer blood pressure (BP)-lowering medications, despite multiple prospective clinical trials reporting both improved normalization of BP 24h patterning and reduced cardiovascular disease (CVD) events when ingested at bedtime rather than upon awakening. Areas covered: We revi...
Article
Introduction and objectives: Ambulatory blood pressure (BP) better predicts cardiovascular disease (CVD) outcomes than office BP measurements (OBPM). Nonetheless, current CVD risk stratification models continue to rely on exclusively daytime OBPM along with traditional factors, eg, age, sex, smoking, dyslipidemia, and/or diabetes. Methods: Data...
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Full-text available
Purpose of review: Current hypertension guidelines do not provide recommendation on when-to-treat. Herein, we review the current evidence on ingestion-time differences of hypertension medications in blood pressure (BP)-lowering effects and prevention of cardiovascular disease (CVD) events. Recent findings: The vast (81.6%) majority of the 136 pu...
Article
Daytime office blood pressure (BP) measurements (OBPM), still recommended and utilized today for diagnosis and management of hypertension and categorization of cardiovascular disease (CVD) risk, fail to reveal clinically important features of the mostly predictable BP 24h pattern and leads to a large proportion of individuals being misclassified. M...
Article
Introduction Office blood pressure measurements (OBPM), still used today for diagnosis and management of hypertension, fail to reveal clinically important features of the mostly predictable blood pressure (BP) 24 h pattern, and lead to >45% of individuals being misclassified. Current hypertension guidelines do not provide recommendation on when-to-...
Article
Introduction Several different interpretive algorithms (IAs) are available for scoring actigraphy-obtained body movement data for sleep and wake epochs. Although most have high sensitivity in detecting sleep epochs, they identify wake epochs poorly. We derived a machine learning (ML) based IA that improves differentiation of sleep and wake epoch to...
Article
Background Estimation of sleep parameters by wrist actigraphy is highly dependent on performance of the interpretative algorithm (IA) that converts movement data into sleep/wake scores. Research Questions (1) Does actigraphy mode of operation -- Proportional Integrating Measure (PIM) or Zero Crossing Mode (ZCM), responsive respectively to intensit...
Article
Numerous prospective studies establish that elevated asleep blood pressure (BP) constitutes a significant cardiovascular disease (CVD) risk factor, irrespective of daytime office BP measurements or awake and 24 h BP measurements. Moreover, except for a small number of studies with flawed methodology, multiple clinical trials of high consistency doc...
Article
The rapid emergence of new measurement instruments and methods requires personnel and researchers of different disciplines to know the correct statistical methods to utilize to compare their performance with reference ones and properly interpret findings. We discuss the often-made mistake of applying the inappropriate correlation and regression sta...
Article
Resumen Diversos estudios prospectivos han demostrado de forma concordante que la elevación en la media de descanso de la presión arterial (PA) constituye un factor de riesgo cardiovascular (CV) significativo e independiente de la PA clínica, o de las medias de actividad o de 24 horas derivadas de la monitorización ambulatoria de la PA. Además, múl...
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OBJECTIVE: The study aimed to explore clock hour, day-of-week, and month-of-year patterns of serious falls experienced by non-institutionalized Spanish seniors (age ≥65 years) in relation to associated conventional intrinsic and extrinsic factors. PATIENTS AND METHODS: Intake emergency department records from January 1 to December 31, 2013 of a te...
Article
We compared performance in deriving sleep variables by both Fitbit Charge 2™, which couples body movement (accelerometry) and heart rate variability (HRV) in combination with its proprietary interpretative algorithm (IA), and standard actigraphy (Motionlogger® Micro Watch Actigraph: MMWA), which relies solely on accelerometry in combination with it...
Article
We compared performance of four popular interpretative algorithms (IAs), i.e., Cole–Kripke, Rescored Cole–Kripke, Sadeh, and UCSD, utilized to derive sleep parameters from wrist actigraphy data. We conducted in-home sleep study of 40 healthy adults (17 female/23 male; age 26.7 ± 12.1 years), assessing sleep variables both by Motionlogger® Micro Wat...
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Background Wearable sleep monitors are of high interest to consumers and researchers because of their ability to provide estimation of sleep patterns in free-living conditions in a cost-efficient way. Objective We conducted a systematic review of publications reporting on the performance of wristband Fitbit models in assessing sleep parameters and...
Preprint
Full-text available
BACKGROUND Wearable sleep monitors are of high interest to consumers and researchers because of their ability to provide estimation of sleep patterns in free-living condition in a cost-efficient way. OBJECTIVE We conducted a systematic review of publications reporting performance of wristband Fitbit models in assessing sleep parameters and stages....
Article
The cost-effectiveness of ambulatory blood pressure (BP) monitoring (ABPM) versus traditional office BP measurement (OBPM) for the diagnosis and management of hypertension has been evaluated only by few studies and based solely on the reduction of medical care expenses through avoiding treatment of isolated-office hypertension. Data from the 21963...
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ABSTRACT We assessed the 24-h pattern of operations-related injuries (ORI) experienced by scheduled off- site/on-call French volunteer firefighters (VFF) through analysis of an archival database. Occurrence and severity – evaluated by number of lost work days (LWD) and total medical costs (TMC) – of ORI were explored in terms of risk ratios, respec...
Article
Elevated asleep heart rate (HR) is a risk factor for cardiovascular disease and other-cause morbidity and mortality. We assessed the accuracy of Fitbit Inc. PurePulse® photoplethysmography with reference to three-lead electrocardiography (ECG) in determining HR during sleep. HR of 35 (17 female) healthy adults 25.1 ± 10.6 years of age (mean ± SD) w...
Article
Water-based passive body heating (PBHWB) as a warm shower or bath before bedtime is often recommended as a simple means of improving sleep. We searched PubMed, CINAHL, Cochran, Medline, PsycInfo, and Web of Science databases and extracted pertinent information from publications meeting predefined inclusion and exclusion criteria to explore the effe...
Article
Domestic accidents pose serious threats to the independence of the elderly. We explored associations between domestic accidents and gender, socioeconomic, medical, and environmental factors using data from the European Health Survey 2014 for elderly Spanish female and male nationals. Records of 5960 participants (mean age ± SD: 75.9 ± 7.6 years), 5...
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This consensus report summarizes the negative impact of work-related psychosocial factors and job stressors on the health and wellbeing of shift workers. Psychosocial factors may (a) directly affect work schedules or (b) mediate or moderate relationships between work schedules, circadian factors, and health. In this paper, prominent psychosocial mo...
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The circadian time structure (CTS) has long been the subject of research in occupational medicine, but not to industrial toxicology, including methods of setting threshold limit values (TLVs) and employee biological monitoring. Numerous animal and human investigations document vulnerability to chemical, contagion, and other xenobiotics varies accor...
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Details of serious injuries to children ≤16 yrs. of age that necessitated urgent surgical intervention by the Department of Pediatric Surgery of the University Hospital of Lausanne, Switzerland were recorded into a database registry. Some 15 110 entries listed the precise time of injury, and 3114 (20.6%) of these resulted from participating in spor...
Conference Paper
Full-text available
Multiple workplace xenobiotic, physical, and psychosocial factors can affect employee wellbeing and health, particularly when working nights. The human circadian time structure (CTS) is an unappreciated, yet potentially important consideration to establishing threshold limiting values, employee biological monitoring (BM) procedures, and recommended...
Article
Diagnosis of hypertension – elevated blood pressure (BP) associated with increased cardiovascular disease (CVD) risk – and its management for decades have been based primarily on single time-of-day office BP measurements (OBPM) assumed representative of systolic (SBP) and diastolic BP (DBP) during the entire 24h span. Around-the-clock ambulatory bl...
Article
The circadian time structure (CTS) and its disruption by rotating and nightshift schedules relative to work performance, accident risk, and health/wellbeing have long been areas of occupational medicine research. Yet, there has been little exploration of the relevance of the CTS to setting short-term, time-weighted, and ceiling threshold limit valu...
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Systolic (S) and diastolic (D) blood pressures (BP) [SBP and DBP] are circadian rhythmic with period (τ) in healthy persons assumed to be maintained at 24.0h. We tested this assumption in a sample of 30 healthy career (mean >12 yrs) 30-to-46 yr-old male Caucasian French firefighters (FFs) categorized into three groups according to work schedule and...
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The invention of electric light has facilitated a society in which people work, sleep, eat, and play at all hours of the 24-hour day. Although electric light clearly has benefited humankind, exposures to electric light, especially light at night (LAN), may disrupt sleep and biological processes controlled by endogenous circadian clocks, potentially...
Article
The bases for bedtime hypertension chronotherapy (BHCT) as superior chronoprevention against cardiovascular disease (CVD) are: (1) correlation between blood pressure (BP) and various risks is greater for ambulatory BP monitoring (ABPM) than office BP measurements (OBPM); (2) asleep BP mean is a better predictor of CVD risk than ABPM awake and 24-ho...
Article
Consistent evidence of numerous studies substantiates the asleep blood pressure (BP) mean derived from ambulatory BP monitoring (ABPM) is both an independent and a stronger predictor of cardiovascular disease (CVD) risk than are daytime clinic BP measurements or the ABPM-determined awake or 24-hour BP means. Hence, cost-effective adequate control o...
Article
We are pleased to read the recently featured Cardiology News article published in Circulation .1 The article highlights research findings demonstrating the important role that circadian clock genes play in regulating cardiac and vascular physiology and, based on animal experiments, the negative consequences of circadian disruption on recovery after...
Article
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This fact-finding expedition explores the perspectives and knowledge of the origin and functional relevance of the 7 d domain of the biological time structure, with special reference to human beings. These biological rhythms are displayed at various levels of organization in diverse species – from the unicellular sea algae of Acetabularia and Gonia...
Article
Background: A potentially important factor yet to receive adequate study is the time when hospital falls occur. A prior study conducted before the system-wide introduction of preventive measures revealed a biphasic 24-hour pattern of hospital falls with major peak in the morning. Objectives: The purpose was to identify the temporal patterning of...
Article
Biological processes are organized in time as innate rhythms defined by the period (τ), phase (peak [Φ] and trough time), amplitude (A, peak-trough difference) and mean level. The human time structure in its entirety is comprised of ultradian (τ < 20 h), circadian (20 h > τ < 28 h) and infradian (τ > 28 h) bioperiodicities. The circadian time struc...
Article
Correlation between blood pressure (BP) and target organ damage, vascular risk, and long-term patient prognosis is greater for measurements derived from around-the-clock ambulatory BP monitoring than in-clinic daytime ones. Numerous studies consistently substantiate the asleep BP mean is both an independent and much better predictor of cardiovascul...
Article
Full-text available
Cereus peruvianus (Peruvian apple cactus) is a large erect and thorny succulent cactus characterized by column-like (cereus [L]: column), that is, candle-shaped, appendages. For three successive years (1100 days), between early April and late November, we studied the flowering patterns of eight cacti growing in public gardens and rural areas of nor...
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Biological rhythmicity is presumed to be an advantageous genetic adaptation of fitness and survival value resulting from evolution of life forms in an environment that varies predictably-in-time during the 24 h, month, and year. The 24 h light/dark cycle is the prime synchronizer of circadian periodicities, and its modulation over the course of the...
Article
In most persons, blood pressure (BP) rises slowly during late sleep; increases rapidly upon morning awakening and commencement of diurnal activity; exhibits two -- morning and afternoon/early evening -- daytime peaks; minor midday nadir, and decline during nighttime sleep by 10 to 20% in systolic BP and somewhat lesser amount in diastolic BP relati...
Chapter
Correlation between blood pressure (BP) and target organ damage, cardiovascular disease (CVD) risk, and long-term prognosis is greater for ambulatory BP monitoring (ABPM) than daytime in-clinic measurements. Additionally, consistent evidence from numerous studies substantiates that ABPM-determined asleep BP mean is an independent and stronger predi...
Chapter
Blood pressure (BP) exhibits significant 24 h variation; in most normotensive and uncomplicated hypertensive persons, BP declines during the first half of nighttime sleep by 10–20 % from its daytime mean level, starts rising in the second half of sleep, further increases with commencement of diurnal activity, and peaks in the afternoon or early eve...
Article
Correlation between blood pressure (BP) and target organ damage, vascular risk and long-term patient prognosis is greater for measurements derived from around-the-clock ambulatory BP monitoring than in-clinic daytime ones. Numerous studies consistently substantiate the asleep BP mean is both an independent and a much better predictor of cardiovascu...
Article
Full-text available
New information has become available since the ISC, AAMCC, and SECAC released their first extensive guidedelines to improve the diagnosis and treatment of adult arterial hypertension. A critical assessment of evidence and a comparison of what international guidelines now propose are the basis for the following statements, which update the recommend...
Article
The aminoglycoside antibiotic gentamicin can cause both ototoxicity and nephrotoxicity, the severity of which varies with circadian time of daily treatment. However, it is not yet resolved if such drug-induced adverse effects are independent or interdependent phenomena. Two groups of 9 female Sprague-Dawley rats (200-250 g), each housed separately...
Article
Routine exposure to artificial light at night (ALAN) in work, home, and community settings is linked with increased risk of breast and prostate cancer (BC, PC) in normally sighted women and men, the hypothesized biological rhythm mechanisms being frequent nocturnal melatonin synthesis suppression, circadian time structure (CTS) desynchronization, a...
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The purpose of this pilot study was to explore the utility of the mammalian swine model under simulated intensive care unit (sICU) conditions and mechanical ventilation (MV) for assessment of the trajectory of circadian rhythms of sedation requirement, core body temperature (CBT), pulmonary mechanics (PM) and gas exchange (GE). Data were collected...
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Simon Folkard in 1997 introduced the phrase black time to draw attention to the fact that the risk of driving accidents (DA) is greater during the night than day in usually diurnally active persons. The 24 h temporal pattern in DA entails circadian rhythms of fatigue and sleep propensity, cognitive and physical performance, and behavior that are co...
Conference Paper
Background. We aimed to determine if the risk of work related injuries (WRI) of French Volunteer Firefighters (VFF) and their severity are greater during the night than day. Studies on VFF are a major interest of the French civil security program since they constitute 78% of the total number of 244 900 French firefighters. VFF maintain a regular jo...
Article
Phototherapy, ie, bright light therapy, is an effective and safe treatment of major depressive disorder (MDD). It exerts rapid mood-elevating activity, similar to antidepressant medications, most likely mediated through both monoaminergic and circadian system melatonergic mechanisms. We assessed the efficiency of bright light therapy as an adjuvant...
Article
Two undesired effects of the aminoglycoside antibiotic gentamicin are ototoxicity and nephrotoxicity. This study investigated if these adverse effects vary according to the circadian time of its administration. This study entails laboratory animal research. Four groups of Sprague-Dawley rats were synchronized to a 12:12 light/dark schedule. Each gr...