Exercise-induced Hypertension and Carotid Intima-media Thickness in Male Marathon Runners.

This study aimed to identify the relationship between exercise-induced hypertension and carotid artery intima-media thickness in long-distance runners. Sixty healthy male runners aged 40 to 60 years were assigned to the following three groups based on resting blood pressure and maximal systolic blood pressure during a maximal exercise test: normal blood pressure response, exercise-induced hypertension, and complex hypertension. An exaggerated systolic blood pressure response was defined as a maximal systolic blood pressure+≥+210 mmHg during the maximal exercise test, while carotid intima-media thickness was measured using B-mode ultrasonography. The carotid intima-media thickness mean values were the highest in the complex hypertension group (0.72±0.11 mm), followed by exercise-induced hypertension (0.62±0.12 mm) and normal blood pressure groups (0.55±0.13 mm), with a significant difference between the groups (p+<+0.002). In linear regression analysis, the mean intima-media thickness was independently associated with age (p=0.015) and maximal systolic blood pressure (p=0.046) but not with resting systolic blood pressure. These results suggest that exercise-induced hypertension is associated with carotid intima-media thickness, a surrogate marker of cardiovascular disease, in long-distance runners. Therefore, evaluating the blood pressure response during exercise is important for the early detection of potential cardiovascular disease risks in long-distance runners.

Association between Perceived Psychological Stress and Exercise Behaviors: A Cross-Sectional Study Using the Survey of National Physical Fitness.

BACKGROUND: Perceived psychological stress and exercise are bidirectionally related, and the effects of exercise on stress relief are well documented. However, research on the influence of stress on exercise remains scarce. This study examined the association between perceived psychological stress and exercise participation among Korean adults and older adults as well as the relationship between exercise frequency and perceived stress. METHODS: Data on 3440 participants (2813 adults aged 19-64 and 627 older adults aged 65 or more) were collected from the Survey of National Physical Fitness conducted by the Korea Institute of Sport Science and the Korean Ministry of Culture, Sports and Tourism in 2015. We compared the participants' health-related behaviors, including exercise, regular breakfast consumption, and smoking, according to their perceived psychological stress levels. RESULTS: Those who perceived a higher level of psychological stress reported lower levels of exercise participation, regular breakfast consumption, and smoking, with the exception of older male participants. The study also found that a higher frequency of exercise participation corresponded with a lower perceived level of psychological stress (ß = -0.080, p < 0.001) and that engaging in physical activity even once a week yields a substantial reduction in stress levels. CONCLUSIONS: In a large sample of Koreans, high levels of perceived psychological stress were significantly associated with less physical activity and infrequent weekly exercise. This study found a dose-response relationship between exercise frequency and reduced stress and suggested that psychological stress should be considered crucial in promoting physical activity.

Effect of high-intensity circuit training on obesity indices, physical fitness, and browning factors in inactive female college students.

The recently discovered myokines, irisin and fibroblast growth factor-21, have emerged beneficial for metabolic health due to their role in regulating browning. This study examined the effects of high-intensity circuit training on obesity indices, physical fitness, and irisin and fibroblast growth factor-21 levels in inactive female college students. Ten female college students performed high-intensity circuit training (jogging, stretching, squat jumps, arm walking and push-ups, lunge jumps, burpee test, mountain climbers, side steps, and crunches and side crunches exercises). The exercise program consisted of 40 min of circuit training at 60%-80% hear rate reserve and was conducted 3 times per week for 4 weeks. The body composition, physical fitness, and concentration of plasma irisin and fibroblast growth factor-21 were analyzed before and after the exercise. The body weight (P=0.001), waist circumference (P=0.003), and body fat percentage (P=0.003) decreased, while the muscular strength (handgrip strength test, P=0.030; sit-ups test, P=0.024) and cardiorespiratory fitness (P=0.001) increased after the exercise program. However, there were no significant changes in the irisin and fibroblast growth factor-21 levels. These results suggest that high-intensity circuit training could be the ideal type of exercise in inactive female college students to induce a positive change in the obesity indices and physical fitness. Further studies are needed to determine the effects of exercise on the browning factors.

Effect of uphill walking on browning factor and high molecular weight-adiponectin in postmenopausal women.

Metabolic disorders occurring in menopause, including dyslipidemia, disorders of carbohydrate metabolism, components of metabolic syndrome, constitute risk factors for cardiovascular disease in women. Irisin and fibroblast growth factor-21 (FGF-21), which regulate browning, and high molecular weight (HMW) adiponectin have emerged beneficial for metabolic health. The purpose of the study was to examine the effect of endurance aerobic exercise on circulating browning factor and HMW-adiponectin level in postmenopausal women. Twenty-five postmenopausal women were included in this study. The aerobic exercise program consisted of 60 min of walking exercise at 50%-60% maximum oxygen uptake, and conducted 3 times per week for 6 weeks. Body composition, blood pressure, lipid profiles, physical fitness, and concentration of plasma irisin, FGF-21, HMW-adiponectin were analyzed before and after exercise. Waist circumference, systolic blood pressure, and triglyceride levels decreased, and levels of high-density lipoprotein cholesterol, irisin increased after exercise. However, there were no significant changes in FGF-21 and HMW-adiponectin. Balance and flexibility among physical fitness indices improved after exercise. These results suggested that moderate intensity walking could be the ideal type of exercise in menopausal women to induce a positive change in metabolic health markers, including an increase in irisin levels. Further studies are needed to determine the effects of exercise on brown adipose tissue browning factor.

The acute effects of interrupting prolonged sitting with stair climbing on vascular and metabolic function after a high-fat meal.

PURPOSE: Frequent consumption of high-fat meals and prolonged sedentary time are prevalent lifestyles that have been associated with an increased risk of vascular and metabolic complications. This study evaluated the acute effects of interrupting prolonged sitting with stair climbing on vascular and metabolic function after a high-fat meal. METHODS: In a randomized, cross-over trial, 12 healthy adults (age: 23.5 ± 2.9 years) consumed a high-fat meal, followed by either 1) a 4-h uninterrupted sitting (sitting trial) or 2) a 4-h sitting interrupted with a 5-min stair climbing (average intensity: 66% of heart rate reserve) every hour (interrupted trial). Plasma triglyceride and glucose concentrations, as well as popliteal artery blood flow and shear rate were assessed at baseline and every hour after a high-fat meal, whereas brachial artery flow-mediated dilation was assessed at baseline and again at the end of each trial. RESULTS: Plasma triglyceride and glucose concentrations increased after a high-fat meal and returned to baseline at the end of both trials. Following a high-fat meal, brachial artery flow-mediated dilation decreased in the sitting trial, but not in the interrupted trial (sitting trial: 9.65 ± 2.63% to 7.84 ± 2.36%; interrupted trial: 9.41 ± 2.61% to 10.34 ± 3.30%, p = 0.009 for interaction). Compared with the sitting trial, the interrupted trial improved popliteal blood flow and shear rate (p = 0.004 and p = 0.008 for interaction, respectively). CONCLUSIONS: These findings suggest that interrupting prolonged sitting with stair climbing may be an effective lifestyle strategy to prevent against vascular dysfunction that might occur as a result of prolonged sitting after consuming a high-fat meal in young healthy adults.

Relation of Exercise Heart Rate Recovery to Predict Cardiometabolic Syndrome in Men.

We examined the hypothesis that delayed heart rate recovery (HRR) after exercise testing, an estimate of decreased autonomic function, predicts the risk of cardiometabolic syndrome (MetS) and is associated with continuous MetS risk scores in healthy men. Participants were 2,740 men who underwent general health examinations and had no evidence of MetS, cardiovascular diseases, diabetes, and hypertension at baseline. Baseline HRR was calculated as the difference between peak heart rate attained during exercise testing and the heart rate at 1 (HRR 1) and 2 minutes (HRR 2) after test termination. Incident MetS was defined as participants having ≥3 MetS components, and continuous MetS risk score was computed as the sum of z-score of 5 risk factors at follow-up. The incidence of MetS was 61/1,000 person-years during an average follow-up of 5 years. The relative risks and 95% confidence interval (CI) of incident MetS in the lowest quartiles of HRR 1 and HRR 2 versus the highest quartile were 1.24 (95% CI 1.02 to 1.51) and 2.02 (95% CI 1.58 to 2.60), respectively, after adjusting for potential confounders, including peak oxygen uptake and resting heart rate. HRR 1 (ß = -0.052, p = 0.005) and HRR 2 (ß = -0.058, p = 0.009) were independently associated with clustered MetS risk scores after adjusting for covariates. In conclusion, the independent association between delayed HRR after exercise testing and incident MetS and continuous MetS risk scores suggests that decreased autonomic function may be considered as a parameter to predict the future likelihood of MetS.

Metabolically healthy obesity and subclinical atherosclerosis in persons with spinal cord injury.

OBJECTIVE: Despite preserved metabolic function, metabolically healthy obesity may increase the risk of subclinical atherosclerosis. Given the high prevalence of cardiometabolic diseases in individuals with spinal cord injury, the aim of this study was to investigate the association of insulin resistance, systemic low-grade inflammation, and markers of subclinical atherosclerosis with metabolically healthy obesity in individuals with spinal cord injury. METHODS: Insulin resistance index (HOMA-IR), high-sensitivity C-reactive protein, carotid artery intima-media thickness and carotid-femoral pulse wave velocity were measured in individuals with spinal cord injury classified with metabolically healthy obesity (n = 12), metabolically unhealthy obesity (n = 8), or metabolically healthy normal-weight (n = 18). Metabolically healthy obesity was defined as spinal cord injury-specific cut-off of body mass index ≥ 22 kg/m2 with < 3 metabolic abnormalities. RESULTS: There were no differences in HOMA-IR or high-sensitivity C-reactive protein in metabolically healthy obesity compared with metabolically healthy normal-weight (p > 0.05). Pulse wave velocity was higher in metabolically healthy obesity than in metabolically healthy normal-weight (p ≤ 0.05), but lower than in metabolically unhealthy obesity (p ≤ 0.05). Metabolically healthy obesity had similar carotid artery intima-media thickness vs metabolically healthy normal-weight (p > 0.05), but lower carotid artery intima-media thickness compared with metabolically unhealthy obesity (p ≤ 0.05). CONCLUSION: Despite a somewhat preserved metabolic and inflammatory status, individuals with spinal cord injury with metabolically healthy obesity present with an intermediate subclinical atherosclerotic phenotype, as evidenced by increased aortic stiffness but not carotid thickness.

Carotid artery reactivity during sympathetic activation following acute resistance exercise.

OBJECTIVE: Acute resistance exercise has been shown to reduce brachial endothelial function. Whether there are concomitant reductions in carotid endothelial function remains unexplored. METHODS: Cold pressor test-mediated vasodilation of the carotid artery was used to assess carotid endothelial function in 15 young and healthy participants (age 26 ± 1 years, body mass index 24 ± 1 kg/m2) after acute resistance exercise or an inactive time control condition. RESULTS: Acute resistance exercise had no effect on the cold pressor test-mediated vasodilation compared to time control (5.8 ± 0.8 vs 6.2 ± 0.9% dilation, p > 0.05). INTERPRETATION: Carotid endothelial function may not be compromised following acute resistance exercise in young healthy adults.

Impact of Cardiorespiratory Fitness and Risk of Systemic Hypertension in Nonobese Versus Obese Men Who Are Metabolically Healthy or Unhealthy.

Few data are available regarding the influence of body phenotype on systemic hypertension (SH) and whether cardiorespiratory fitness (CRF) attenuates this relation. We tested the hypothesis that obesity phenotypes and CRF would predict incident hypertension, evaluating 3,800 Korean men who participated in 2 health examinations in1998 to 2009. All participants were normotensive at baseline and were divided into 4 groups based on body mass index using the Asia-Pacific descriptors for obesity and metabolic health status and the National Cholesterol Education Program's adult treatment panel III (ATP-III) criteria. A metabolically healthy obese (MHO) phenotype was defined as a body mass index of ≥25 kg/m2 with <2 metabolic abnormalities. CRF was directly measured by peak oxygen uptake, and the participants were divided into unfit and fit categories based on age-specific peak oxygen uptake percentiles. Compared with the metabolically healthy nonobese phenotype, MHO and metabolically unhealthy nonobese (MUNO) phenotypes were at increased risk of SH (relative risk [RR] = 1.47; 95% confidence interval [CI], 1.07 to 2.02 and 1.62, 1.21 to 2.16) after adjusting for potential confounders. Joint analysis showed that MHO or MUNO unfit men had 1.91 and 2.27 greater risk of incident SH, respectively. However, MHO fit men had no significant RR of incident SH (RR 1.37; 95% CI, 0.93 to 2.03), whereas MUNO fit men remained at increased risk (RR 1.48; 95% CI, 1.04 to 2.11) compared with their metabolically healthy nonobese fit counterparts. In conclusion, MHO and MUNO men were at increased risk of SH, but these risks were attenuated by fitness.

Relation of heart rate recovery after exercise testing to coronary artery calcification.

BACKGROUND: We examined whether slow heart rate recovery (HRR) after exercise testing as an estimate of impaired autonomic function is related to coronary artery calcification (CAC), an emerging marker of coronary atherosclerosis. METHODS: We evaluated 2088 men who participated in a health-screening program that included measures of CAC and peak or symptom-limited cardiopulmonary exercise testing. HRR was calculated as the difference between peak heart rate (HR) during exercise testing and the HR at 2 min of recovery after peak exercise. We measured CAC using multidetector computed tomography to calculate the Agatston coronary artery calcium score. Advanced CAC was defined as a mean CAC >75th percentile for each age group. RESULTS: HRR was negatively correlated with CAC (r = -.14, p < .01). After adjusting for conventional risk factors, participants in the lowest quartile of HRR (<38 bpm) were 1.59 times (95% CI: 1.17-2.18; p < .05) more likely to have advanced CAC than their counterparts in the highest quartile of HRR (>52 bpm). Each 1 bpm decrease in HRR was associated with 1% increase in advanced CAC after adjusting for potential confounders. CONCLUSIONS: An attenuated HRR after exercise testing is associated with advanced CAC, independent of coronary risk factors and other related hemodynamic response. KEY MESSAGES Slow heart rate recovery (HRR) after maximal exercise testing, indicating decreased autonomic function, is associated with an increased risk of cardiovascular event and mortality. Slow HRR has been linked with the occurrence of malignant ventricular arrhythmias, but it remains unclear whether slow HRR is associated with an increased risk of coronary artery calcification (CAC), an emerging marker of coronary atherosclerosis. An attenuated HRR after exercise testing was associated with advanced CAC, independent of coronary risk factors and other potential hemodynamic confounder, supporting the hypothesis that slow HRR is related to the burden of atherosclerotic coronary artery disease.

Fitness, Body Habitus, and the Risk of Incident Type 2 Diabetes Mellitus in Korean Men.

The relative contributions of cardiorespiratory fitness (CRF) and body habitus to predict incident type 2 diabetes mellitus (T2DM) remain unclear. We prospectively investigated the relation of CRF and body habitus on the risk of developing T2DM in men. Participants included 3,770 apparently healthy men who initially presented without baseline evidence of diabetes, cardiovascular disease, and hypertension. Participants were divided into 3 groups as normal weight (18.5 to 24.9 kg/m(2)), obese I (25.0 to 29.9 kg/m(2)), and obese II (≥30.0 kg/m(2)). CRF was directly measured by peak oxygen uptake (VO2peak) and categorized into unfit and fit cohorts based on the median value of age-specific VO2peak. Diabetes was defined as a glycated hemoglobin >6.5% and/or a fasting glucose >126 mg/dl at baseline and follow-up examinations. During a median follow-up of 5 years, 170 men (4.5%) developed diabetes. After adjusting for age and fasting glucose, the relative risk and 95% confidence interval (CI) for incident T2DM were 1.52 (95% CI 1.11 to 2.07) for obese I and 3.11 (95% CI 1.35 to 7.16) for obese II versus normal weight and 0.69 (95% CI 0.51 to 0.95) for fit versus unfit. However, these associations were no longer statistically significant after adjusting for potential confounders with VO2peak (1.32; 95% CI 0.96 to 1.83 for obese I and 1.61, 95% CI 0.64 to 4.06 for obese II vs normal weight) or body mass index (0.75, 95% CI 0.54 to 1.05 for fit vs unfit). In the joint analysis, obese-unfit men had 1.81 times (95% CI 1.22 to 2.69) greater risk of incident T2DM, but obese-fit men were not at increased risk of incident T2DM (0.95, 95% CI 0.57 to 1.58) compared with fit-normal weight men. In conclusion, these results suggest that both CRF and obesity predict the incidence of T2DM independent of potential confounders; however, CRF appears to attenuate the risk of developing diabetes in obese men.

The Relationship Between Cardiorespiratory Fitness and Aortic Stiffness in Women with Central Obesity.

PURPOSE: To examine the association between cardiorespiratory fitness and aortic stiffness in women with central obesity. The secondary purpose was to examine whether traditional and nontraditional cardiovascular risk factors mediate the relationship between cardiorespiratory fitness and aortic stiffness. MATERIALS AND METHODS: Eighty-seven centrally obese women (age, 42 ± 9 years, [body mass index (BMI)] 28 ± 3 kg/m(2)) participated in this cross-sectional study. Central obesity was defined as a waist circumference >85 cm. Pulse wave velocity (PWV) was obtained from the carotid and femoral pulse sites using applanation tonometry to measure aortic stiffness. Maximal aerobic capacity (VO2 Max) was estimated using a submaximal walk test and taken as a measure of cardiorespiratory fitness. Potential correlates of both cardiorespiratory fitness and aortic stiffness examined in this study included the following: triglycerides (TG), C-reactive protein (CRP), homeostasis model assessment of insulin resistance index (HOMA-IR), and pulsatile load (i.e., heart rate × aortic pulse pressure [aPP]). RESULTS: Pearson's bivariate correlations indicated that estimated VO2 Max was inversely associated with PWV (r = -0.330, p < 0.05). Using hierarchical multiple regression, the association between estimated VO2 Max and PWV was no longer significant after controlling for traditional and nontraditional cardiovascular risk factors, age, BMI, TG, CRP, HOMA-IR, and pulsatile load (ß = 0.121, p > 0.05). CONCLUSION: In centrally obese women, cardiorespiratory fitness was inversely associated with aortic stiffness. Associations were not independent of traditional and nontraditional cardiovascular disease (CVD) risk factors. This suggests that higher levels of cardiorespiratory fitness may indirectly reduce aortic stiffness through its beneficial effects on traditional and nontraditional CVD risk factors in women with central obesity.

Effects of Acute Active Video Games on Endothelial Function Following a High-Fat Meal in Overweight Adolescents.

BACKGROUND: We tested the hypothesis that an active video game following a high-fat meal would partially prevent the unfavorable effect of a high-fat meal on vascular function in overweight adolescents. METHODS: Twenty-four overweight adolescents were randomized to either a 60-minute active video game (AVG) group (n = 12) or seated rest (SR) as a control group (n = 12) after a high-fat meal. Blood parameters were measured, and vascular function was measured using brachial artery flow-mediated dilation (FMD) at baseline and 3 hours after a high-fat meal. RESULTS: No significant interaction was found in any blood parameter. A high-fat meal significantly increased blood triglyceride and glucose concentrations in both groups in a similar manner. Brachial artery FMD significantly decreased in the SR group (13.8 ± 3.2% to 11.8 ± 2.5), but increased in the AVG group (11.4 ± 4.0% to 13.3 ± 3.5), with a significant interaction (P = .034). CONCLUSION: These findings show that an active video game attenuated high-fat meal-induced endothelial dysfunction. This suggests that an active video game may have a cardioprotective effect on endothelial function in overweight adolescents when exposed to a high-fat meal.

Effects of combined aerobic and resistance exercise on central arterial stiffness and gait velocity in patients with chronic poststroke hemiparesis.

OBJECTIVE: The effects of combined aerobic and resistance exercise training on central arterial stiffness and gait velocity in patients with chronic poststroke hemiparesis were investigated. DESIGN: Twenty-six patients with chronic poststroke hemiparesis were randomly assigned to either the combined aerobic and resistance exercise group (n = 14) or the control group (n = 12). The exercise intervention group received a combined aerobic and resistance exercise training (1 hr/day, three times/week for 16 wks), whereas the control group received usual care. Central arterial stiffness was determined by pulse wave velocity and augmentation index. Gait velocity was assessed using the 6-min walk test, 10-m walk test, and the Timed Up-and-Go test. RESULTS: Patients in the exercise intervention group had greater improvement of mean pulse wave velocity (P < 0.001), augmentation index (P = 0.048), and gait velocity (6-min walk test, P < 0.001; 10-m walk test, P < 0.001) than did patients in the control group. Patients in the exercise intervention group also had greater improvements in physical fitness component (grip strength, P < 0.001; muscular strength of upper and lower limbs, P < 0.027; flexibility, P < 0.001) when compared with control patients. CONCLUSIONS: The combined aerobic and resistance exercise program significantly reduced central arterial stiffness and increased gait velocity in patients with chronic poststroke hemiparesis.

Associations of arterial stiffness and cognitive function with physical fitness in patients with chronic stroke.

OBJECTIVE: To determine whether arterial stiffness is associated with cognitive function after adjustment for physical fitness in patients with chronic stroke. METHODS: Cross-sectional analyses were conducted in 102 patients with chronic stroke who participated in an exercise rehabilitation programme. Carotid femoral pulse wave velocity and augmentation index were measured as indices of arterial stiffness and central systolic loading. Cognitive function was assessed with the Mini Mental State Examination. Parameters of physical fitness included the 6-min walk test, flexibility, balance, and muscle strength tests. RESULTS: Carotid femoral pulse wave velocity was significantly associated with Mini Mental State Examination (r = -0.45, p < 0.01) and parameters of physical fitness (r = -0.45~ -0.55, p < 0.01, all). Mini Mental State Examination was significantly associated with parameters of physical fitness (r = 0.32~0.46, p < 0.01, all). In multivariable linear regression models, carotid femoral pulse wave velocity was inversely associated with Mini Mental State Examination after adjustment for multiple risk factors (beta = -0.33, p = 0.01). However, the association was attenuated and became non-significant after additional adjustment for physical fitness (beta = -0.11, p = 0.39). CONCLUSION: Arterial stiffness measured by carotid femoral pulse wave velocity is associated with cognitive function in patients with chronic stroke, but not after adjustment for physical fitness. Maintaining appropriate levels of physical fitness may have a favourable effect on both vascular and cognitive function in patients with stroke.

Effect of cardiorespiratory fitness on acute inflammation induced increases in arterial stiffness in older adults.

We tested the hypothesis that acute inflammation may cause arterial stiffening in older adults. We further explored if high cardiorespiratory fitness may partially prevent the unfavorable effect of arterial stiffening produced by acute systemic inflammation in older adults. Using a randomized double-blind sham placebo-controlled design, forty healthy older adults were assigned to receive either an influenza vaccine or a sham vaccine. C-reactive protein and interleukin 6 (IL-6) were measured as markers of inflammation. Carotid-femoral pulse wave velocity (PWV) and augmentation index (AIX) as indices of arterial stiffness and wave reflection were assessed at baseline and 24 and 48 h after each vaccination. When compared with sham placebo, the influenza vaccination caused a significant increase in CRP (p < 0.05) and IL-6 (p < 0.05). Carotid-femoral PWV, but not AIX was significantly increased after influenza vaccination (p < 0.05), but not sham vaccination. The high cardiorespiratory fitness group had an attenuated increase in PWV as compared to the low cardiorespiratory fitness group after acute inflammation (p < 0.05). These findings show that acute inflammation may cause significant increases in arterial stiffness in older adults, but these increases were attenuated in the high cardiorespiratory fitness group as compared to the low cardiorespiratory fitness group.

Resistance exercise training reduces arterial reservoir pressure in older adults with prehypertension and hypertension.

We examined changes in central blood pressure (BP) following resistance exercise training (RET) in men and women with prehypertension and never-treated hypertension. Both Windkessel theory and wave theory were used to provide a comprehensive examination of hemodynamic modulation with RET. Twenty-one participants (age 61±1 years, n=6 male; average systolic blood pressure (SBP)/diastolic blood pressure (DBP)=138/84 mm Hg) were randomized to either 12 weeks of RET (n=11) or an inactive control group. Central BP and augmentation index (AIx) were derived from radial pressure waveforms using tonometry and a generalized transfer function. A novel reservoir-wave separation technique was used to derive excess wave pressure (related to forward and backward traveling waves) and reservoir pressure (related to the capacitance/Windkessel properties of the arterial tree). Wave separation using traditional impedance analysis and aortic flow triangulation was also applied to derive forward wave pressure (Pf) and backward wave pressure (Pb). There was a group-by-time interaction (P<0.05) for central BP as there was a significant ~6 mm Hg reduction in SBP and ~7 mm Hg reduction in DBP following RET with no change in the control condition. There were also group-by-time interactions (P<0.05) for Pf, excess wave pressure and reservoir pressure attributable to reductions in these parameters in the RET group concomitant with slight increases in the control group. There was no change in AIx or Pb (P>0.05). RET may reduce central BP in older adults with hypertension and prehypertension by lowering Pf and reservoir pressure without affecting pressure from wave reflections.

Temporal changes in cardiorespiratory fitness and the incidence of hypertension in initially normotensive subjects.

OBJECTIVES: Low-cardiorespiratory fitness (CRF) has been associated with incident hypertension, but whether temporal changes in CRF are associated with incident hypertension in initially normotensive subjects are not known. We investigated the relationship of baseline CRF and longitudinal changes in CRF with incident hypertension in initially normotensive subjects. METHODS: Subjects were 3,831 men who participated in two health examinations during 1998-2009. All subjects were free of cardiovascular diseases and hypertension at baseline. CRF was directly measured by peak oxygen uptake using expired gas analysis during a standard treadmill test. RESULTS: During an average of 5 years of follow-up, 373 (9.7%) subjects developed hypertension. The incidence of hypertension was inversely associated with baseline CRF quartiles [Q1 (lowest) 11.8%, Q2 10.4%, Q3 9.1%, and Q4 (highest) 7.5%; P < 0.05 for trend]. The relative risk (RR) of incident hypertension in the lowest CRF quartile versus the highest CRF quartile was 1.69 (95% CI: 1.22-2.34) after adjustment for risk factors. Each metabolic equivalent increment higher peak oxygen uptake at baseline examination was associated with 10% (RR 0.90, 95% CI: 0.83-0.98) lower incidence of hypertension in multivariate adjusted model. Subjects whose CRF decreased (<-1.18 ml/kg/min per year) over time had a 72% increased risk in developing hypertension (RR 1.72, 95% CI: 1.20-2.49) compared to subjects with increased CRF (>0.13 ml/kg/min per year) after adjustment for risk factors. CONCLUSION: These results demonstrate that both baseline CRF levels and changes in CRF over time were associated with the incidence of hypertension independent of risk factors.

Pulsatile stress, inflammation and change in arterial stiffness.

AIM: Understanding factors that contribute to changes in arterial stiffness over time is important as this may lead to therapies that can abrogate cardiovascular risk. We compared the contribution of pulsatile stress and inflammation to changes in arterial stiffness in middle-aged men using a 1-year follow-up study design. METHODS: Arterial stiffness was derived from brachial-ankle pulse wave velocity (baPWV) in 107 men (mean age 53±6 yrs) on two separate occasions. The changes in outcome variables were calculated as the difference between the first and second examinations (mean interval 403±122 days). Pulsatile stress was calculated as the product of heart rate and brachial pulse pressure. C-reactive protein (CRP), white blood cell count (WBC) and fibrinogen were measured as inflammatory markers. RESULTS: At baseline, baPWV was significantly correlated with pulsatile stress (r=0.37, p<0.01), WBC (r=0.19, p<0.05), HbA1c (r=0.39, p<0.01), HDL-C (r=.0.20, p<0.05), but not CRP (r= 0.06, p=0.56), or fibrinogen (r=0.12, p=0.21). The change in baPWV over 1 year was associated with the change in pulsatile stress (r=0.26, p<0.01) and HbA1c (r=0.19, p<0.05) over that same time period. Change in baPWV was not associated with the change in WBC (r=0.18, p=0.06) or CRP (r=0.05, p=0.62). CONCLUSIONS: These results demonstrate that both pulsatile stress and inflammation may be associated with arterial stiffness at any given moment in time, but change in pulsatile stress is a better predictor of change in arterial stiffness over time.

Effect of increased preload on the synthesized aortic blood pressure waveform.

In the present study, we examined the influence of preload augmentation via passive leg elevation (PLE) on synthesized aortic blood pressure, aortic augmentation index (AIx), and aortic capacitance (a reflection of aortic reservoir function). Central and peripheral hemodynamics were measured via tonometry with a generalized transfer function in 14 young, healthy men (age = 24 yr). Aortic blood flow was calculated from the left ventricular outflow tract (LVOT) velocity-time integral (VTI) using standard two-dimensional echocardiographic-Doppler techniques. Measures were made in the supine position at rest (Pre), during PLE, and during recovery (Post). There was a significant increase in LVOT-VTI, synthesized aortic systolic blood pressure (BP) and AIx from Pre to PLE, with values returning to baseline Post (P < 0.05). There was a reduction in aortic capacitance from Pre to PLE, with values returning to baseline Post (P < 0.05). There was no change in heart rate, systemic arterial compliance, aortic elastance, aortic wave travel timing, or vascular resistance (P > 0.05). Change in AIx from Pre to PLE was associated with change in LVOT-VTI (r = 0.66, P < 0.05) and inversely associated with change in aortic capacitance (r = -0.73, P < 0.05). These data suggest that in a setting of isolated augmented preload with minimal changes in other potential confounders, the morphology of the synthesized aortic BP waveform and AIx may be related to changes in aortic reservoir function.