Kenneth R Wilund

University of Illinois, Urbana-Champaign, Urbana, Illinois, United States

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Publications (70)216.77 Total impact

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    ABSTRACT: Ventricular and vascular coupling is defined as the ratio of arterial elastance (Ea) to ventricular elastance (Elv) and describes the interaction between the heart and arterial system. There are sex differences in both arterial and ventricular function in response to both acute exercise and aerobic exercise training.
    European journal of applied physiology. 08/2014;
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    ABSTRACT: Abstract The polyphenolic compound resveratrol (RSV) has been studied for its protective effects on a variety of conditions, including cardiovascular disease (CVD), reduced exercise capacity, and bone disease. Individuals with chronic kidney disease suffer from a variety of these comorbid conditions, but the efficacy of RSV supplementation in this population is unknown. The objective of this study was to determine the efficacy of resveratrol feeding on factors related to CVD, aerobic capacity, and bone health in a mouse model of uremia. At 8 weeks of age, 28 female apolipoprotein E(-/-) mice underwent a two-step surgical procedure to induce uremia and were randomized to one of the two treatment groups for 16 weeks: 0.04% w/w resveratrol supplemented diet (group designated as RSV) (n=12) or control diet (group designated as CON) (n=16). Cardiovascular risk was determined by analysis of aortic atherosclerotic lesion area and aortic calcium, aerobic capacity was measured by maximal oxygen consumption/maximal aerobic capacity (VO2max) testing, and bone microarchitecture was assessed by microcomputed tomography. RSV animals had significantly fewer aortic atherosclerotic lesions at the site of the ascending aorta and lower aortic calcium at the branch of the coronary arteries compared with CON. Furthermore, there was a significant decline in VO2max from baseline to final testing in the CON group, but VO2max was preserved in the RSV group. Last, RSV had no significant effect on bone architecture. These data indicate that RSV supplementation improves vascular health and preserves aerobic capacity in a model of uremia, suggesting RSV supplementation could be examined as a therapeutic strategy for a critically ill population.
    Journal of medicinal food 01/2014; · 1.39 Impact Factor
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    ABSTRACT: Acute inflammation reduces flow-mediated vasodilation (FMD) and increases arterial stiffness in young healthy individuals. However, this response has not been studied in older adults. Therefore, the aim of this study was to evaluate the effect of acute induced systemic inflammation on endothelial function and wave reflection in older adults. Furthermore, an acute bout of moderate intensity aerobic exercise can be anti-inflammatory. Taken together, we tested the hypothesis that acute moderate intensity endurance exercise, immediately preceding induced inflammation, would be protective against the negative effects of acute systemic inflammation on vascular function. Fifty-nine healthy volunteers between 55 - 75 years of age were randomized in an exercise or control group. Both groups received a vaccine (induced inflammation) and sham (saline) injection in a counterbalanced crossover design. Inflammatory markers, endothelial function (FMD) and measures of wave reflection and arterial stiffness were evaluated at baseline, 24 hours and 48 hours after injections. There were no significant differences in endothelial function and arterial stiffness between the exercise and control group after induced inflammation. The groups were then analyzed together and we found significant differences in the inflammatory markers 24 and 48 hours post-acute inflammation compared to sham injection. However, FMD, augmentation index normalized for heart rate (AIx75) and β-stiffness did not change significantly. Our results suggest that acute inflammation induced by influenza vaccination did not affect endothelial function in older adults.
    Experimental physiology 01/2014; · 3.17 Impact Factor
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    ABSTRACT: Blood flow restriction (BFR) exercise may be an alternative form of resistance training; however, a side of effect of BFR resistance exercise is acute muscle pain. Typically, BFR exercise studies restrict blood flow with a cuff continuously during the exercise bout, including rest periods. However, others have used intermittent BFR where the cuff is inflated only during sets. We performed two studies to compare intermittent and continuous BFR exercise. In study one, eleven subjects randomly proceeded through three treatments of unilateral leg extensions to failure: (i) continuous BFR, (ii) intermittent BFR and (iii) control (exercise without BFR). Pain measurements were taken immediately after each set. In study two, subjects (n = 32) underwent a 5-week resistance training programme after random assignment to one of the three conditions. Lean mass and strength were assessed at baseline and after training. Continuous BFR resulted in significantly greater pain than intermittent BFR or control. Both BFR conditions resulted in significantly fewer repetitions to failure than control. This suggests that an acute bout of intermittent BFR exercise may produce as much muscle fatigue as an acute bout of continuous BFR exercise, but with less pain. With training, maximal knee extension (P = 0·033) and maximum knee flexion (P = 0·007) strength increased among all groups. There were no significant differences between groups in strength or lean mass. These results suggest that short-term low-load resistance training increases muscle strength to a similar extent as low-load resistance training without BFR.
    Clinical Physiology and Functional Imaging 11/2013; · 1.33 Impact Factor
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    ABSTRACT: African American (AA) men have higher arterial stiffness and augmentation index (AIx) than Caucasian (CA) men. Women have greater age-associated increases in arterial stiffness and augmentation index (AIx) than men. This study examined racial and sex differences in arterial stiffness and central hemodynamics at rest and following an acute bout of maximal exercise in young healthy individuals. One hundred young, healthy individuals (28 AA men, 24 AA women, 25 CA men and 23 CA women) underwent measurements of aortic blood pressure (BP) and arterial stiffness at rest, 15 minutes and 30 minutes following an acute bout of graded maximal aerobic exercise. Aortic BP and AIx were derived from radial artery applanation tonometry. Aortic stiffness (carotid-femoral) was measured via pulse wave velocity. Aortic stiffness (P < 0.05) following an acute bout of maximal cycling exercise increased in AA but not in CA, after controlling for BMI. Aortic BP decreased following exercise in CA but not in AA (p< 0.05). Women exhibited greater reductions in AIx following maximal aerobic exercise compared to men (p< 0.05). Race and sex impact the vascular and central hemodynamic response to exercise. Young AA and CA exhibited differential responses in central stiffness and central BP following acute maximal exercise. Premenopausal women had greater augmented pressure at rest and following maximal aerobic exercise than men. Future research is needed to examine the potential mechanisms.
    AJP Heart and Circulatory Physiology 11/2013; · 4.01 Impact Factor
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    ABSTRACT: The current investigation examined whether patients undergoing hemodialysis (HD) have reduced standing postural control performance during simultaneous cognitive task performance (i.e. dual task cost (DTC)) compared to age-gender matched controls. 19 persons undergoing HD and 19 age, gender, and body mass index (BMI) matched controls participated in the investigation. All participants performed 2 trials of quiet standing balance and 2 postural trials in which they performed a cognitive task. Postural control was indexed with various measures of the center of pressure (COP) trajectory. The change in postural control with a cognitive task (e.g. dual task cost DTC) was quantified as a change in the center of COP parameters of postural control from quiet standing to the cognitive condition. The primary observations were that (1) HD patients had significantly greater postural sway than age, gender, BMI matched controls (p's<0.05); (2) HD patients had a greater DTC than the controls during quiet standing (p's<0.05). The observations highlight that HD participants have poor postural control that is further exacerbated by a simultaneous performance of a cognitive task. It is possible that this impaired postural control places HD participants at elevated fall risk. Further study is necessary to determine contributing factors to an increased DTC in this population and whether targeted interventions such as exercise can reduce DTC.
    Gait & posture 10/2013; · 2.58 Impact Factor
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    ABSTRACT: Intensive care unit (ICU)-acquired weakness is common and characterized by muscle loss, weakness, and paralysis. It is associated with poor short-term outcomes, including increased mortality, but the consequences of reduced long-term outcomes, including decreased physical function and quality of life, can be just as devastating. ICU-acquired weakness is particularly relevant to elderly patients who are increasingly consuming ICU resources and are at increased risk for ICU-acquired weakness and complications, including mortality. Elderly patients often enter critical illness with reduced muscle mass and function and are also at increased risk for accelerated disuse atrophy with acute illness. Increasingly, intensivists and researchers are focusing on strategies and therapies aimed at improving long-term neuromuscular function. β-Hydroxy-β-methylbutyrate (HMB), an ergogenic supplement, has shown efficacy in elderly patients and certain clinical populations in counteracting muscle loss. The present review discusses ICU-acquired weakness, as well as the unique physiology of muscle loss and skeletal muscle function in elderly patients, and then summarizes the evidence for HMB in elderly patients and in clinical populations. We subsequently postulate on the potential role and strategies in studying HMB in elderly ICU patients to improve muscle mass and function.
    Journal of Parenteral and Enteral Nutrition 09/2013; · 2.49 Impact Factor
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    ABSTRACT: There is minimal data on the gait of hemodialysis (HD) patients with and without diabetes. This investigation examined spatiotemporal parameters of gait in HD patients with and without diabetes compared with age-matched, sex-matched, and BMI-matched controls. The effect of muscle weakness on gait in HD patients was also examined. Eighteen HD patients and 18 age-matched, sex-matched, and BMI-matched controls completed two walking trials along a 7.9 m long pressure sensitive pathway. The HD participants were divided into groups based on their diabetic status (eight patients without diabetes and 10 with diabetes). Spatiotemporal markers of gait, including variability metrics, were determined. Knee strength was quantified only in the HD groups. Overall HD patients had a worse gait compared with controls (P<0.01). Furthermore, HD patients with diabetes had an elevated gait variability compared with those without diabetes, even after controlling for muscle strength (P<0.05). Further research is warranted to explore whether increases in lower extremity strength lead to improvements in gait in this population.Es liegen nur sehr wenige Daten zum Gang von Hämodialyse-Patienten (HD) mit oder ohne Diabetes vor. Bei der vorliegenden Untersuchung wurden spatio-temporale Parameter des Gangs bei HD-Patienten mit und ohne Diabetes mit Personen ähnlichen Alters, gleichen Geschlechts und ähnlichen BMI aus einer Kontrollgruppe verglichen. Bei den HD-Patienten wurde auch die Wirkung der Muskelschwäche auf den Gang untersucht. Insgesamt 18 HD-Patienten und 18 Personen ähnlichen Alters, gleichen Geschlechts und ähnlichen BMI aus einer Kontrollgruppe nahmen an zwei Gangstudien entlang eines 7.9 m langen druckempfindlichen Pfads teil. Die Teilnehmer an der HD-Studie wurden entsprechend ihres Diabetes-Status (acht Patienten ohne Diabetes, 10 mit Diabetes) in Gruppen unterteilt. Ermittelt wurden spatio-temporale Marker des Gangs, darunter die Variabilität von Metriken. Die Kniestärke wurde ausschließlich in den HD-Gruppen quantifiziert. Die HD-Patienten wiesen im Vergleich mit der Kontrollgruppe einen insgesamt schlechteren Gang auf (P's<0.01). Darüber hinaus wiesen HD-Patienten mit Diabetes eine höhere Gangvariabilität auf als diejenigen ohne Diabetes, selbst nach der Kontrolle der Muskelkraft (P<0.05). Im Rahmen weiterer Untersuchungen ist zu ermitteln, ob ein Anstieg der Muskelkraft in den unteren Extremitäten bei dieser Population zu einer Verbesserung des Gangs führt.En la actualidad existe un número mínimo de datos sobre la marcha de pacientes con hemodiálisis (HD) con y sin diabetes. En este estudio se examinaron los parámetros espaciotemporales de la marcha de pacientes con HD con y sin diabetes, comparándolos con controles de la misma edad, sexo e IMC. También se analizó el efecto de la debilidad muscular en la marcha de individuos con HD. Dieciocho sujetos con HD y 18 controles de la misma edad, sexo e IMC llevaron a cabo dos pruebas de marcha en una pista de 7.9 m sensible a la presión. Los participantes con HD fueron divididos en dos grupos en función de su condición diabética (ocho pacientes sin diabetes y 10 con diabetes). A continuación, se determinaron los marcadores espaciotemporales de la marcha, incluidas las mediciones de variabilidad. La fuerza de la rodilla se cuantificó solamente en los grupos con HD. En general, los pacientes con HD mostraron una marcha más deficiente que la de los controles (P's<0.01). Por otro lado, los pacientes con HD con diabetes presentaron una variabilidad elevada de la marcha en comparación con los pacientes sin diabetes, incluso después de realizarse las pruebas de fuerza muscular (P<0.05). Es necesario llevar a cabo más estudios que determinen si el aumento en la fuerza de las extremidades inferiores provoca una mejora de la marcha en esta población.Il existe peu de données sur la démarche des patients diabétiques et non-diabétiques sous hémodialyse (HD). Cette étude examinait les paramètres spatio-temporels de la marche chez les patients diabétiques et non-diabétiques sous HD par rapport à des patients témoins d'âge correspondant, appariés en termes de sexe et d'IMC. L'effet de la faiblesse musculaire sur la marche chez les patients sous HD a également été examiné. Dix-huit patients sous HD et 18 patients témoins appariés en termes d'âge, de sexe et d'IMC ont effectué deux tests de marche le long d'un passage de 7.9m sensible à la pression. Les participants sous HD ont été divisés en groupes selon leur état diabétique (huit patients non diabétiques et 10 diabétiques). Les marqueurs spatio-temporels de la démarche, y compris les mesures de variabilité, ont été déterminés. La force du genou n'a été quantifiée que pour les groupes sous HD. Globalement, les patients sous HD présentaient une plus mauvaise démarche que les groupes témoins (P <0.01). En outre, les patients diabétiques sous HD présentaient une variabilité accrue de la démarche par rapport aux non-diabétiques, même après contrôle de la force musculaire (P <0.05). D'autres recherches seront nécessaires pour déterminer si une augmentation de la force des extrémités inférieures conduirait à des améliorations de la démarche chez cette population.
    International journal of rehabilitation research. Internationale Zeitschrift fur Rehabilitationsforschung. Revue internationale de recherches de readaptation 07/2013; · 0.36 Impact Factor
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    ABSTRACT: Background : End-stage renal disease patients experience increased prevalence of cardiovascular disease. Heart-artery interaction may be shifted, impacting blood pressure lability, and exercise tolerance. The coupling ratio consists of the ratio of indexed arterial elastance (EaI, arterial load) to ElvI, a measure of cardiac contractility or stiffness. Our purpose was to explore the relationship between elastances and functional capacity. We hypothesized that arterial stiffness (central pulse wave velocity, PWV) and elastances would be correlated to shuttle walk time. Methods : We used applanation tonometry, ultrasonography, and a shuttle walk test to evaluate our hypothesis. Spearman's correlations were used to assess relationships between variables. Block regression was also performed. Results: Forty-two subjects on maintenance hemodialysis participated. Average age=44±5 years, body surface area=2.01 kg/m(2). Mean EaI=4.45 and mean ElvI=6.89; the coupling ratio=0.82. Mean aortic pulse pressure=51 mmHg and PWV=9.6 m/s. PWV(r=-0.385) and EaI (r=-0.424) were significantly and inversely related to walking time while stroke volume index (SVI) was positively correlated to shuttle walk time (r=0.337), p<0.05 for all. Conclusions: We conclude that, like other clinical populations, both arterial and heart function predict walking ability and represent potential targets for intervention; arterial stiffness and SVI are strongly related to shuttle walk time in patients with ESRD.
    Kidney and Blood Pressure Research 04/2013; 37(2-3):142-150. · 1.60 Impact Factor
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    ABSTRACT: Wasted left ventricular effort (∆Ew) refers to work required of the left ventricle to eject blood that does not result in increased stroke volume and is related to left ventricular hypertrophy. Literature shows that men and women have differing ventricular and vascular responses to and following exercise. Our purpose was to determine how ∆Ew changes post-exercise in men and women and examine potential mechanisms. We hypothesized a reduction in ∆Ew that would be greater in men and that central pulse wave velocity and wave intensity (WIA) would be related to ∆Ew. Blood pressures, central pulse wave velocity (cPWV), and WIA were obtained at rest, 15 and 30 min after maximal exercise. Both sexes reduced ∆Ew post-maximal exercise (p>0.05 for interaction), but women had higher ∆Ew at each time point (p<0.05). The first peak of WIA increased 15 min post-exercise only in women (p<0.05). cPWV was attenuated (p<0.05) in women at 15 min and men at 30 min (p<0.05) post-exercise with a significant time by sex interaction (p<0.05). WIA (1st peak) was correlated (p<0.05) to ∆Ew in both sexes before and 15 min post-exercise, but cPWV was only associated with ∆Ew in men at 30 min post-exercise. We conclude that both sexes decrease ∆Ew after maximal exercise, but vascular and ventricular changes associated with the attenuation of ∆Ew are not uniform between sexes.
    International Journal of Sports Medicine 03/2013; · 2.27 Impact Factor
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    ABSTRACT: The relationship between effective arterial elastance (E(A)) and left ventricular end-systolic elastance (E(LV)) is a determinant of cardiac performance, known as arterial-ventricular coupling (AVC). The purpose of this study was to examine the acute effects of high-intensity interval (HI) and low-intensity steady state (SS) exercise on AVC. Twenty-three (13 men, 10 women) young (26 years), endurance-trained individuals completed a VO(2) peak test followed by an acute SS and HI exercise bout on separate visits. Before (Pre) and 30- and 60-min after each bout, measures of aortic end-systolic pressure (ESP), left ventricular end-systolic volume and stroke volume were obtained. Across both conditions (HI and SS) and both sexes, at 30 and 60 min post exercise, ESP and E(LV) were reduced from Pre 30 and 60-min exercise (ESP: 86±7, 77±8 and 73±8 mm Hg; E(LV): 4.93±1.53, 4.19±1.38 and 4.10±1.53 mm Hg ml(-1) m(-2)). E(A) was only reduced at 60 min post exercise (1.90±0.36, 1.78±0.50 and 1.57±0.36). Both E(A) and E(LV) were reduced following acute SS and HI exercise. This is likely because of similar reductions in total peripheral resistance following both exercise bouts. These results suggest that endurance-trained individuals are able to match peripheral vascular changes with changes in left ventricular function following dynamic exercise of different intensities.Journal of Human Hypertension advance online publication, 21 February 2013; doi:10.1038/jhh.2013.7.
    Journal of human hypertension 02/2013; · 2.80 Impact Factor
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    ABSTRACT: Muscle loss is common during aging and chronic diseases, such as cancer and acquired immunodeficiency syndrome. Moreover, muscle loss has been correlated with decreased physical function, quality of life, and mortality in these populations. Therefore, interventions to counteract muscle loss in the elderly and clinical populations are needed. Recently, the efficacy of the leucine metabolite, β-hydroxy-β-methylbutyrate (HMB), to maintain muscle mass has been investigated in these populations. Many studies have found increases in lean mass and strength in the elderly and clinical populations when using HMB; however, not all studies have found beneficial effects of HMB supplementation. The present review summarizes published human studies investigating the efficacy of HMB supplementation in the elderly and clinical populations. In addition, the mechanisms by which HMB may exert its effects are summarized and future research directions are suggested.
    Nutrition 10/2012; · 2.86 Impact Factor
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    ABSTRACT: Aortic reservoir function is a measure of the aorta's ability to distribute blood during diastole, attenuating the pulsatility of blood flow, and is important in balancing cardiac flow. Effects of acute high versus moderate exercise intensity on reservoir function and cardiac energetics is unknown. Eighteen athletes completed a interval (INT) and steady-state (SS) cycling bout at 60% of VO(2) peak. Reservoir function was calculated as the ratio of diastolic run-off to stroke volume and expressed as a percentage. Coronary perfusion pressure was derived from tissue Doppler imaging and echocardiography. Systolic tension-time integral (TTI) from the aortic pressure waveform served as a measure of myocardial oxygen consumption. All measures were made at rest, 30-min postexercise and 60-min postexercise. Average reservoir function before SS was 76%, which was reduced to 62% 30-min post-SS and 67% 60-min post-SS (P<0.05). Significantly greater reductions in reservoir function were seen following INT (from 71% pre-INT to 45% 30-min post-INT and 53% 60-min INT, P<0.05). Estimated coronary perfusion pressure was reduced 30 min following INT but not SS; both bouts reduced coronary perfusion pressure at 60-min postexercise (P<0.05). TTI increased following both INT and SS at 30- and 60-min postexercise with greater increases following INT (P<0.05). Following exercise, reservoir function was associated with TTI (P<0.05), but not coronary perfusion pressure (P>0.05). We conclude that reservoir function is attenuated following acute SS and INT, but these reductions were greater post-INT, suggesting that exercise intensity affects reservoir function. Reduction of reservoir function following exercise is related to TTI, a reflection of myocardial oxygen consumption but apparently not associated with coronary perfusion pressure.
    Clinical Physiology and Functional Imaging 09/2012; 32(5):353-60. · 1.33 Impact Factor
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    ABSTRACT: Shin S, Chung HR, Kistler BM, Fitschen PJ, Wilund KR, Sosnoff JJ. Walking and talking in maintenance hemodialysis patients. OBJECTIVES: To investigate whether there is a reduction in walking with the simultaneous performance of a cognitive task (ie, dual-task cost [DTC]) in persons undergoing hemodialysis (HD), and whether it is greater in persons undergoing HD compared with age-matched controls. DESIGN: Cohort. SETTING: University research laboratory. PARTICIPANTS: Persons undergoing HD (n=14; 5 women, 9 men; mean age ± SD, 50.0±11.8y) and age-matched controls (n=14; 4 women, 10 men; mean age ± SD, 48.5±10.1y) participated in the investigation. INTERVENTIONS: Not applicable. MAIN OUTCOMES MEASURES: Participants walked at a self-selected pace on an electronic pathway, which recorded spatiotemporal parameters of gait, in 4 separate trials and completed a cognitive task in the last 2 trials. The DTC was quantified as the change in spatiotemporal parameters of gait from baseline to the cognitive trials. RESULTS: The HD group had a greater decrease in walking function during the cognitive task, with DTC ranging from 6% to 14%. On average, walking velocity decreased to less than 1m/s in HD patients during the cognitive condition. Baseline walking velocity was found to be moderately correlated with the magnitude of DTC of cadence and step time (ρ=-.44 and .46; P values <.05). CONCLUSIONS: Persons undergoing HD have greater interference between walking and talking compared with controls. Difficulty walking while thinking has implications for everyday life and may be related to the risk of falls. Further work is necessary to determine other contributing factors to elevated DTC in HD patients, and whether DTC can be reduced with targeted interventions.
    Archives of physical medicine and rehabilitation 07/2012; · 2.18 Impact Factor
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    ABSTRACT: OBJECTIVES: Left ventricular end systolic pressure (LV ESP) is important in assessing left ventricular performance and is usually derived from prediction equations. It is unknown whether these equations are accurate at rest or following exercise in a young, healthy population. DESIGN: Measured LV ESP vs. LV ESP values from the prediction equations were compared at rest, 15min and 30min following peak aerobic exercise in 60 participants. METHODS: LV ESP was obtained by applanation tonometry at rest, 15min post and 30min post peak cycle exercise. RESULTS: Measured LV ESP was significantly lower (p<0.05) at all time points in comparison to the two calculated values. Measured LV ESP decreased significantly from rest at both the post15 and post30 time points (p<0.05) and changed differently in comparison to the calculated values (significant interaction; p<0.05). The two LV ESP equations were also significantly different from each other (p<0.05) and changed differently over time (significant interaction; p<0.05). CONCLUSIONS: The two commonly used prediction equations did not accurately predict either resting or post exercise LV ESP in a young, healthy population. Thus, LV ESP needs to be individually determined in young, healthy participants. Non-invasive measurement through applanation tonometry appears to allow for a more accurate determination of LV ESP.
    Journal of science and medicine in sport / Sports Medicine Australia. 06/2012;
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    ABSTRACT: Aging results in chronic low grade inflammation that is associated with increased risk for disease, poor physical functioning and mortality. Strategies that reduce age-related inflammation may improve the quality of life in older adults. Regular exercise is recommended for older people for a variety of reasons including increasing muscle mass and reducing risk for chronic diseases of the heart and metabolic systems. Only recently has exercise been examined in the context of inflammation. This review will highlight key randomized clinical trial evidence regarding the influence of exercise training on inflammatory biomarkers in the elderly. Potential mechanisms will be presented that might explain why exercise may exert an anti-inflammatory effect.
    Aging and disease. 02/2012; 3(1):130-40.
  • Emily J Tomayko, Hae R Chung, Kenneth R Wilund
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    ABSTRACT: Soy protein consumption and exercise training have been widely studied for their effects on the vasculature and bone in healthy populations, but little is known about the effectiveness of these interventions in chronic kidney disease (CKD). Cardiovascular disease and bone fracture risk are significantly elevated in CKD, and current pharmacological interventions have been unsuccessful in treating these conditions simultaneously. The purpose of this study was to compare the effects of a soy protein diet and endurance exercise training, alone or in combination, on cardiovascular and bone health in a mouse model of renal insufficiency. At 8 weeks of age, 60 female apolipoprotein E(-/-) mice underwent a two-step surgical procedure to induce uremia. These mice were then randomized at 12 weeks of age to one of four treatment groups for the 16-week intervention period: sedentary, control diet (n = 16); sedentary, soy protein diet (n = 18); exercise, control diet (n = 14); and exercise, soy protein diet (n = 12). There were no significant treatment effects on atherosclerotic lesion areas or aortic calcium deposits. We demonstrated a significant main effect of both diet and exercise on relative bone volume, trabecular number, trabecular separation, and trabecular connective density in the proximal femur as measured by microcomputed tomography. There were no treatment effects on trabecular thickness. We also showed a main effect of diet on plasma urea levels. These data suggest that soy protein intake and exercise training exert beneficial effects on properties of bone and plasma urea levels in mice with surgically induced renal impairment.
    Journal of Bone and Mineral Metabolism 06/2011; 29(6):682-90. · 2.22 Impact Factor
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    ABSTRACT: This study examined whether a commercially available fish-oil supplement offers protection from the acute effects of a high-fat meal (HFM) on endothelial function and arterial stiffness. An HFM causes acute impairments in endothelial function, whereas the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have a variety of cardioprotective effects. However, little is known about the efficacy of moderate fish-oil supplementation on the endothelial dysfunction induced by an HFM. Endothelial function (brachial artery flow-mediated dilation (FMD)), forearm blood flow (FBF), total hyperemia, central and peripheral blood pressure, and central artery stiffness were assessed in 20 healthy men (n = 10) and women (n = 10) at rest and 4 h after an HFM supplemented with either placebo or approximately 1 g EPA and DHA. Brachial artery FMD normalized for shear rate was significantly impaired (p = 0.033) following the HFM with placebo but remained unchanged compared with baseline following the HFM with the fish-oil supplement (p = 0.039; condition x time interaction). Resting FBF (p = 0.020) and total hyperemia (p = 0.014) were elevated following the HFM. All other vascular and hemodynamic measurements were unchanged in both trials. Commercially available fish-oil supplements taken with an HFM appear to preserve endothelial function following an HFM.
    Applied Physiology Nutrition and Metabolism 06/2010; 35(3):294-302. · 2.01 Impact Factor
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    ABSTRACT: The acute effect of high-intensity interval exercise (HI) on blood pressure (BP) is unknown although this type of exercise has similar or greater cardiovascular benefits compared to steady-state aerobic exercise (SS). This study examined postexercise hypotension (PEH) and potential mechanisms of this response in endurance-trained subjects following acute SS and HI. Sex differences were also evaluated. A total of 25 endurance-trained men (n = 15) and women (n = 10) performed a bout of HI and a bout of SS cycling in randomized order on separate days. Before exercise, 30 min postexercise, and 60 min postexercise, we measured brachial and aortic BP. Cardiac output (CO), stroke volume (SV), end diastolic volume (EDV), end systolic volume (ESV), and left ventricular wall-velocities were measured using ultrasonography with tissue Doppler capabilities. Ejection fraction and fractional shortening (FS), total peripheral resistance (TPR), and calf vascular resistance were calculated from the above variables and measures of leg blood flow. BP, ejection fraction, and FS decreased by a similar magnitude following both bouts but changes in CO, heart rate (HR), TPR, and calf vascular resistance were greater in magnitude following HI than following SS. Men and women responded similarly to HI. Although men and women exhibited a similar PEH following SS, they showed differential changes in SV, EDV, and TPR. HI acutely reduces BP similarly to SS. The mechanistic response to HI appears to differ from that of SS, and endurance-trained men and women may exhibit differential mechanisms for PEH following SS but not HI.
    American Journal of Hypertension 04/2010; 23(4):358-67. · 3.67 Impact Factor
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    ABSTRACT: Cardiovascular disease (CVD) mortality rates are greatly elevated in chronic kidney disease patients receiving maintenance haemodialysis therapy. The purpose of this study was to evaluate the efficacy of intradialytic endurance exercise training on novel risk factors that may contribute to this excessive CVD risk. Seventeen haemodialysis patients were randomized to either an intradialytic exercise training (cycling) group (EX; n = 8) or a non-exercising control group (CON; n = 9) for 4 months. At baseline and following the intervention, we measured serum parameters related to CVD risk and renal function, used echocardiography to measure variables related to cardiac structure and function and assessed physical performance by a validated shuttle walk test. Performance on the shuttle walk test increased by 17% in EX (P < 0.05), but did not change in CON. There was no change in serum lipids or inflammatory markers (C-reactive protein, interleukin-6) in either group. Serum thiobarbituric acid reactive substances, a marker of oxidative stress, were reduced by 38% in EX (P < 0.05), but did not change in CON. In addition, serum alkaline phosphatase (ALP), a putative risk factor for vascular calcification, was reduced by 27% in EX (P < 0.05), but did not change in CON. There was no change in left atrial volume, left ventricular mass or myocardial performance index in either group. However, the thickness of the epicardial fat layer was reduced by 11% in EX (P < 0.05), but did not change in CON. Furthermore, the change in physical performance was inversely correlated to the change in epicardial fat (r = -0.63; P = 0.03). These results suggest that endurance exercise training may improve CVD risk in haemodialysis patients by decreasing novel risk factors including serum oxidative stress, ALP and epicardial fat.
    Nephrology Dialysis Transplantation 02/2010; 25(8):2695-701. · 3.37 Impact Factor

Publication Stats

1k Citations
216.77 Total Impact Points

Institutions

  • 2007–2014
    • University of Illinois, Urbana-Champaign
      • • Department of Kinesiology and Community Health
      • • Division of Nutritional Sciences
      Urbana, Illinois, United States
  • 2013
    • University of Oklahoma
      • Department of Health and Exercise Science
      Oklahoma City, OK, United States
    • Kyung Hee University
      • Department of Biomedical Engineering
      Sŏul, Seoul, South Korea
  • 2012–2013
    • University of Illinois at Chicago
      • Department of Kinesiology and Nutrition
      Chicago, IL, United States
  • 1999–2007
    • University of Maryland, College Park
      • Department of Kinesiology
      College Park, MD, United States
  • 2004
    • University of Texas Southwestern Medical Center
      Dallas, Texas, United States
    • Methodist Dallas Medical Center
      Dallas, Texas, United States
  • 1998–2004
    • University of Pittsburgh
      • Division of Cardiology
      Pittsburgh, PA, United States
  • 2002
    • Howard Hughes Medical Institute
      Ashburn, Virginia, United States
    • Sapienza University of Rome
      Roma, Latium, Italy