Joshua M. Bock

Joshua M. Bock
Mayo Clinic - Rochester · Department of Cardiovascular Diseases

Ph.D. - Integrative Physiology

About

50
Publications
2,383
Reads
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221
Citations
Additional affiliations
May 2020 - present
Mayo Clinic
Position
  • PostDoc Position
August 2016 - May 2020
University of Iowa
Position
  • Graduate Assistant
August 2014 - May 2016
Ball State University
Position
  • Graduate Assistant
Education
August 2016 - May 2020
University of Iowa
Field of study
  • Rehabilitation Science
August 2014 - May 2016
Ball State University
Field of study
  • Clinical Exercise Physiology
January 2010 - January 2014
Salisbury University
Field of study
  • Exercise Science

Publications

Publications (50)
Article
Aging is associated with increased peripheral chemoreceptor activity, reduced nitric oxide (NO) bioavailability, as well as attenuation of cardiovagal baroreflex sensitivity (BRS), collectively increasing the risk of cardiovascular disease. Evidence suggests NO may attenuate peripheral chemoreflex sensitivity and increase BRS. Exogenous inorganic n...
Article
Key points: Contraction-mediated blunting of postjunctional α-adrenergic vasoconstriction (functional sympatholysis) is attenuated in skeletal muscle of ageing males, brought on by altered postjunctional α1 - and α2 -adrenergic receptor sensitivity. The extent to which postjunctional α-adrenergic vasoconstriction occurs in the forearms at rest and...
Article
Shear-mediated dilation in peripheral conduit arteries is blunted with sympathetic nervous system (SNS) activation; however, the effect of SNS activation on shear-mediated dilation in carotid arteries is unknown. We hypothesized that SNS activation reduces shear-mediated dilation in common and internal carotid arteries (CCA and ICA, respectively) a...
Article
Habitual aerobic exercise attenuates elevated vasoconstriction during acute exercise (functional sympatholysis) in older men; however, this effect remains unknown in postmenopausal women (PMW). This study tested the hypothesis that, PMW who participate in habitual aerobic exercise, demonstrate a greater functional sympatholysis compared to their un...
Article
Peripheral artery disease (PAD) is characterized by functional and vascular impairments as well as elevated levels of inflammation which are associated with reduced nitric oxide (NO) bioavailability. Inorganic nitrate supplementation boosts NO bioavailability potentially improving functional and vasodilatory capacities and may reduce inflammation....
Article
Background Patients with type 2 diabetes mellitus (T2DM) have increased cardiovascular risk partially due to elevated blood pressure (BP). As low levels of nitric oxide (NO) may contribute to increased BP, we studied the effects of increasing NO bioavailability via 8wks of supplementation with beetroot juice containing inorganic nitrate/nitrite (4....
Article
In America, Black adults are 30% more likely to die from cardiovascular disease (CVD) compared to White adults, and more than half of this racial disparity in CVD-related mortality may be attributed to the substantially greater prevalence of high blood pressure (BP) in Black adults. Furthermore, compared to White adults with hypertension, Black adu...
Article
Stimuli that evoke pain stimulate the sympathetic nervous system leading to downstream vascular and hemodynamic adjustments. In clinical populations and older individuals, the perception of pain is associated with cardiovascular responses (e.g., heart rate, blood pressure, and arterial stiffness). However, there are extensive inter-individual diffe...
Article
Insufficiency or irregularity in sleep is associated with high blood pressure (BP) and aortic stiffness, both of which are independent predictors of all-cause and cardiovascular mortality. The cardiovascular ramifications of short and irregular sleep are well documented in shift workers, but the health implications of possible differences between s...
Article
Full-text available
Objective To determine whether continuous positive airway pressure (CPAP) adherence reduces health care–related costs or use in patients with obstructive sleep apnea (OSA) and comorbid cardiovascular disease (CVD). Patients A total of 23 million patients with CVD were identified in the Medicare fee-for-service database. Of the 65,198 who completed...
Article
Excessive daytime sleepiness (EDS) is classically viewed as a consequence of insufficient sleep or a symptom of sleep disorders. Epidemiological and clinical evidence have shown that patients reporting EDS in tandem with sleep disorders (e.g., obstructive sleep apnoea) are at greater cardiovascular risk than non-sleepy patients. While this may simp...
Article
Full-text available
Background: Ambulatory overnight oximetry (OXI) has emerged as a cost-effective initial test for sleep disordered breathing. Obesity is closely associated with obstructive sleep apnea (OSA); however, whether body mass index (BMI) or waist-to-hip ratio (WHR) predicts abnormal overnight OXI remains unknown. Methods: We performed a retrospective cross...
Article
Background & Aims Peripheral artery disease (PAD) is characterized by elevated blood pressure (BP), low nitric oxide availability (NO), and exaggerated pressor responses to sympatho-excitatory stressors. Inorganic nitrate reduces peripheral BP in healthy and chronically diseased populations. The objective of this study was to investigate the effect...
Article
Aims Patients with type 2 diabetes mellitus (T2DM) have reduced vasodilatory responses during exercise partially attributable to low nitric oxide (NO) levels. Low NO contributes to greater α-adrenergic mediated vasoconstriction in contracting skeletal muscle. We hypothesized boosting NO bioavailability via 8wks of active beetroot juice (BRA, 4.03mm...
Article
While the contribution of several physiological systems to arterial blood pressure regulation has been studied extensively, the role of normal and disrupted sleep as a modifiable determinant of blood pressure control, and in the pathophysiology of hypertension, has only recently emerged. Several sleep disorders, including sleep apnea and insomnia,...
Article
Purpose: We sought to determine if individually calibrated machine learning models yielded higher accuracy than a group calibration approach for physical activity intensity assessment. Methods: Participants (n = 48) wore accelerometers on the right hip and nondominant wrist while performing activities of daily living in a semistructured laborato...
Article
Full-text available
Purpose: Excessive daytime sleepiness is highly prevalent and has been associated with increased risk of cardiovascular diseases, but evidence for its association with cardiovascular mortality is limited and inconsistent. We aimed to determine whether excessive daytime sleepiness is independently associated with cardiovascular mortality in general...
Article
Full-text available
Microvascular endothelial dysfunction precipitates cardiovascular disease mortality in patients with type 2 diabetes mellitus (T2DM). However, the relationship between glycemic management and microvascular endothelial function of these patients remains ill defined. We investigated the association between skeletal muscle microvascular endothelial fu...
Article
Patients with obstructive sleep apnea (OSA) experience repetitive partial or complete airway collapse during sleep resulting in nocturnal hypoxia-normoxia cycling, and are at increased cardiovascular risk. The number of apneas and hypopneas indexed per hour of sleep (AHI) along with the associated intermittent hypoxia predict the increased cardiova...
Article
Aging causes deleterious changes in resting conduit artery shear patterns and reduced blood flow during exercise partially attributable to reduced nitric oxide (NO). Inorganic nitrate increases circulating NO bioavailability and may therefore improve age-associated changes in shear rate as well as exercise hyperemia. 10 older adults (67±3yrs) consu...
Article
The present study is the first to examine the acute effects of inorganic nitrate supplementation on resting blood pressure and cardiopulmonary responses to hypoxia (e.g., peripheral chemoreflex sensitivity) in patients with obstructive sleep apnea (OSA). Our data indicate inorganic nitrate supplementation attenuates an early-morning rise in systoli...
Article
TO THE EDITOR: Recent Point (6) and Counterpoint (3) arguments were made on whether or not to control for the menstrual cycle when assessing vascular function.While both sides present valid arguments for and against controlling for the menstrual cycle phase, we believe this answer is ultimately contingent upon the question(s) being addressed. As no...
Article
The balance of angiogenic factors, including vascular endothelial growth factor (VEGF), and angiostatic factors, like thrombospondin-1 (TSP-1) and endostatin, controls striated muscle angiogenic responses to exercise training. The effect of age on circulating levels of these factors following a bout of exercise is unclear. The authors hypothesized...
Article
Patients with type 2 diabetes mellitus (T2DM) exhibit diminished exercise capacity likely attributable to reduced skeletal muscle blood flow (i.e., exercise hyperemia). A potential underlying mechanism of the impaired hyperemic response to exercise could be inadequate blunting of sympathetic-mediated vasoconstriction (i.e., poor functional sympatho...
Article
Physical activity, especially when performed at moderate or vigorous intensity, has short- and long-term health benefits, but measurement of free-living physical activity is challenging. Accelerometers are popular tools to assess physical activity, although accuracy of conventional accelerometer analysis methods is suboptimal. This study developed...
Article
Cyclic intermittent hypoxia (IH) increases cerebral blood velocity. This enhanced velocity augments the commensurate shear stimulus and may subsequently increase cerebrovascular endothelial function. This study aimed to examine the effects of cyclic IH on hypercapnia-induced shear-mediated dilation of the internal carotid artery (ICA); a potential...
Article
Despite recent popularity of wrist-worn accelerometers for assessing free-living physical behaviours, there is a lack of user-friendly methods to characterize physical activity from a wrist-worn ActiGraph accelerometer. Participants in this study completed a laboratory protocol and/or 3–8 hours of directly observed free-living (criterion measure of...
Article
Full-text available
PurposeBlood flow (BF) and vasodilator responses to knee-extension exercise are attenuated in older adults across an exercise transient (onset, kinetics, and steady-state), and reduced nitric oxide bioavailability (NO) has been hypothesized to be a primary mechanism contributing to this attenuation. We tested the hypothesis acute dietary nitrate (N...
Article
Consumption of a single, sugar-sweetened beverage (SSB) impairs vascular endothelial function. Regular aerobic exercise improves endothelium-dependent vasodilation; however, it's unknown if these beneficial-effects persist with frequent SSB consumption. Therefore, the purpose of this study was two-fold; we studied the effects of repetitive SSB cons...
Article
Background: Age-associated arterial stiffening may be the result of greater tonic sympathetic nerve activity. However, age-associated changes in central artery responsiveness to sympathoexcitatory stimuli are understudied. Therefore, we examined changes in central artery stiffness and wave reflection in response to sympathoexcitatory stimuli in yo...
Article
To the Editor: A recent article by Clanton (1) highlights an insightful Viewpoint regarding the emerging role of myoglobin (Mb) as an interstitial Po2 (PiO2) regulator during exercise by switching from a nitric oxide (NO) consumer to an NO producer. We propose a point of contention that the now well-known role of NO in regulating PiO2 during exerci...
Article
This study aimed to elucidate the effect of aging on shear-mediated dilation of the common and internal carotid arteries (CCA and ICA, respectively). Hypercapnia-induced shear-mediated dilation in the CCA and ICA were assessed in ten young (5F/5M, 23±1 years) and ten older (6F/4M, 68±1 years) healthy adults. Shear-mediated dilation was induced by t...
Article
The vasoactive molecule nitric oxide (NO) contributes to regulation of blood pressure (BP) at rest and during exercise. Age-related exaggerated increased BP responses during exercise have been proposed to be due in part to a decreased NO bioavailability and possibly an enhanced skeletal muscle metaboreflex. In the present study we sought to determi...
Article
Purpose: To enable inter- and intra-study comparisons it is important to ascertain comparability among accelerometer models. This study compared raw and count data between hip-worn ActiGraph GT3X+ and GT9X Link accelerometers. Methods: Adults (n=26 [n=15 women]; aged 49.1±20.0 years) wore GT3X+ and Link accelerometers over the right hip for an 8...
Article
Full-text available
Purpose: Modulation of vascular function follows an exercise intensity-dependent pattern in young adults. This study aimed to investigate the potential intensity-dependent effects of an acute bout of exercise on conduit and resistance artery function in healthy older adults. Methods: Eleven healthy older adults (5 males/6 females, 66±1 years) co...
Article
Full-text available
Limited research exists on the reliability of consumer-based physical activity monitors (CPAMs) despite numerous studies on their validity. Consumers often purchase CPAMs to assess their physical activity (PA) habits over time, emphasizing CPAM reliability more so than their validity; therefore, the purpose of this study was to investigate the reli...
Article
This study compared accuracy of energy expenditure (EE) prediction models from accelerometer data collected in structured and simulated free-living settings. Twenty-four adults (mean age 45.8 years, 50% female) performed two sessions of 11 to 21 activities, wearing four ActiGraph GT9X Link activity monitors (right hip, ankle, both wrists) and a met...
Article
Full-text available
During prolonged, submaximal exercise skeletal muscle uses both carbohydrates (CHO) and lipids as substrates to synthesize adenosine triphosphate (ATP); the fundamental unit of energy This article is protected by copyright. All rights reserved

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