Heart Rate-pressure Product Research Articles

Atropine as an adjunct to supine bicycle stress echocardiography: an alternative strategy to achieve target heart rate or rate pressure product

To investigate the use of atropine to achieve target heart rate (THR) and rate pressure product (RPP) during supine bicycle exercise stress echocardiography (SBESE) to increase the number of diagnostic stress tests. Forty-four patients that were unable to achieve THR or RPP during SBESE performed to evaluate ischaemia were given 0.4-1.2 mg of atropine to augment THR and RPP. After atropine (0.7 ± 0.3 mg) the maximum heart rate (HR) achieved was 133 (± 16) bpm, mean THR was 82% (± 8%), and average RPP was 22 716 (± 4915) b/min × mmHg. Of the patients with a non-diagnostic SBESE, with the use of atropine 80% of those patients achieved a diagnostic test. There were no major adverse affects from the administration of atropine. The use of atropine to augment the HR or RPP during SBESE (i) is safe; (ii) enables the assessment of ischaemia at peak effort; and (iii) allows assessment of exercise haemodynamics in patients with sub-maximal exercise capacity and chronotropic incompetence.

The Effect of Power-walking in Phase 2 Cardiac Rehabilitation Program

ObjectiveTo evaluate the effects of power walking (PW) training on a treadmill in patients with coronary heart disease (CHD) and to compare the cardiovascular effects of PW with usual walking (UW).MethodPatients were recruited as participants in phase 2 cardiac rehabilitation program after receiving percutaneous coronary intervention (PCI) due to acute coronary syndrome from our hospital. The participants were divided into the PW group (n=16) and UW group (n=18). All participants received graded exercise test (GXT) and significant difference in maximal oxygen consumption (VO2Max) was not observed between the groups. Aerobic exercise training on treadmill was given for 50 minutes per session, three times a week, for six weeks. Physiological and hematological parameters were tested before and 6 weeks after the cardiac rehabilitation program. Exercise duration, VO2Max, heart rate, blood pressure, and rate pressure product were evaluated through graded exercise test. Hematological measurements included serum lipid profile, and high-sensitivity C reactive protein (hs-CRP).ResultsThere were no significant differences in resting heart rate, maximal heart rate, resting systolic and diastolic blood pressures, lipid profile, hs-CRP, VO2Max, and RPP between the PW group and UW group. However, after 6 weeks of the intervention, VO2Max in the PW group (36.03±5.69 ml/kg/min) was significantly higher than that in the UW group (29.73±5.63 ml/kg/min) (p<0.05).ConclusionAfter six weeks of phase 2 cardiac rehabilitation program, the PW group showed significant improvement in VO2Max than the UW group. Thus, it will beneficial to recommend power walking in cardiac rehabilitation program.

Cardioprotective effect of diazepam on ischemia-reperfused isolated hyperthyroid rat heart

Hyperthyroidism increases the vulnerability of the heart to ischemia-reperfusion (I/R) injury. Regarding the fact that diazepam also affects cardiac I/R injury, the current study was conducted to investigate the effect of diazepam on ischemia-reperfused isolated hyperthyroid rat heart. The animals were divided into 6 groups: the control, hyperthyroid, control diazepam (1 mg/kg), hyperthyroid diazepam (1 mg/kg), control diazepam (5 mg/kg), and hyperthyroid diazepam (5 mg/kg) groups. Langendorff-perfused rat hearts underwent 40 min of global ischemia and 45 min of reperfusion. Different cardiac parameters, including the left ventricular developed pressure, heart rate, coronary flow, and rate pressure product (RPP), were measured. Lactate dehydrogenase (LDH) release was determined in reperfusion to evaluate the severity of the myocardial injury. The results showed that the RPP recovery percentage significantly decreased in the hyperthyroid group compared with control group, whereas comparison of the hyperthyroid diazepam (1 mg/kg) with the control and control diazepam (1 mg/kg) groups did not reveal a significant difference. These results were confirmed by LDH test, demonstrating that administration of diazepam (1 mg/kg) protected the heart against I/R injury in the hyperthyroid group and significantly decreased the I/R injury, which was probably due to the function of diazepam as a phosphodiesterase 4 inhibitor.

Different Cardiovascular Responses to a Resistance Training Session in Hypertensive Women Receiving Propanolol Compared with Normotensive Controls

The aim of the present study was to compare the responses of blood pressure, heart rate, and rate-pressure product of hypertensive women using beta-blockers with healthy controls during resistance exercise (by the end of the concentric phase of the contractions) and in the postexercise period (5 and 30 minutes after). Ten untrained normotensive women (N) and 10 mildly hypertensive females receiving 40 mg/day of propanolol (H) were selected. Three sets of 10 repetitions at 80% of 10 repetitions maximum with 30 s rest interval were performed on the leg press exercise. The H group exhibited lower systolic blood pressure after the second set compared with N. Heart rate and rate-pressure product were lower in H in all analyzed periods compared with N. Propanolol attenuates the cardiovascular response to a leg press resistance exercise in mildly hypertensive women.

Post exercise cardiovascular effects of different resistance exercise protocols for trunk and upper limbs

Objective: to analyze the post exercise cardiovascular effects of different resistance exercise protocols for trunk and upper limbs. Methods: Fifteen males (22.3 ± 0.9 years) underwent three experimental sessions randomly: control session (C), resistance exercise session at 50% of one repetition maximum (1-RM) (E50%), and resistance exercise session at 70% of 1-RM (E70%). Three sets of 12, 9 and 6 repetitions were performed for each exercise. Blood pressure (BP), heart rate (HR) and rate pressure product (RPP) were measured before and during 90 minutes after each session. Results: Systolic BP decreased (P&lt;.05) and diastolic BP increased (P&lt;.05) similarly after C, E50% and E70%. However, HR and RPP decreased after C (P&lt;.01), maintained after E50%, and increased after E70% (P&lt;.01). Conclusions: The resistance exercise intensity did not influence post-exercise BP responses, however, cardiac overload was greater after E70%

Effects of walking and strength training on resting and exercise cardiovascular responses in patients with intermittent claudication

Exercise training is recommended as the first-line therapy for intermittent claudication patients. However, the effects of exercise therapy on cardiovascular function of these patients have been poorly studied. The aim of this study is to compare the effects of walking and strength training on cardiovascular responses assessed at rest and during exercise in patients with intermittent claudication. Thirty-four patients with stable symptoms of intermittent claudication were randomized into two groups: strength training (ST) consisting of eight exercises, three sets of 10 repetitions, intensity of 11 - 13 on 15-grade Borg scale, 2-min interval between sets; and walking training (WT) consisting of walking on a treadmill, 15 bouts of 2-min, intensity of 11 - 13 on 15-grade Borg scale, with a 2-min interval between bouts. Before and after 12 weeks, blood pressure, heart rate and rate pressure product were measured at rest and during a progressive treadmill test until maximal claudication pain. Fifteen patients in each group completed the training program. After the training programs, resting systolic blood pressure (ST:-6 ± 13 mmHg and WT:-3 ± 18 mmHg, P = .04), heart rate (ST: -6 ± 10 bpm and WT:-2 ± 9 bpm, P = .03), and rate pressure product (ST:-1485 ± 1442 mmHg*bpm and WT:- 605 ± 2145 mmHg*bpm, P = .01) decreased significantly and similarly in both groups. Submaximal systolic blood pressure (ST: -14 ± 23 mmHg and WT:-6 ± 23 mmHg, P = .02), and rate pressure product (ST:-1579 ± 3444 mmHg*bpm and WT: -1264 ± 3005 mmHg*bpm, P = .04) decreased significantly and similarly in both groups. There were no changes in submaximal heart rate after ST and WT. Maximal systolic blood pressure, heart rate, and rate pressure product did not change in either group, although maximal exercise time increased similarly in the ST and WT groups (+31 ± 19 %, and +31 ± 32 %, respectively, P < .01). Strength and walking trainings promoted similar increases in walking capacity and decreases in resting and submaximal exercise cardiovascular load.

Strength and power training did not modify cardiovascular responses to aerobic exercise in elderly subjects

Resistance training increases muscle strength in older adults, decreasing the effort necessary for executing physical tasks, and reducing cardiovascular load during exercise. This hypothesis has been confirmed during strength-based activities, but not during aerobic-based activities. This study determined whether different resistance training regimens, strength training (ST, constant movement velocity) or power training (PT, concentric phase performed as fast as possible) can blunt the increase in cardiovascular load during an aerobic stimulus. Older adults (63.9 ± 0.7 years) were randomly allocated to: control (N = 11), ST (N = 13, twice a week, 70-90% 1-RM) and PT (N = 15, twice a week, 30-50% 1-RM) groups. Before and after 16 weeks, oxygen uptake (VO(2)), systolic blood pressure (SBP), heart rate (HR), and rate pressure product (RPP) were measured during a maximal treadmill test. Resting SBP and RPP were similarly reduced in all groups (combined data = -5.7 ± 1.2 and -5.0 ± 1.7%, respectively, P < 0.05). Maximal SBP, HR and RPP did not change. The increase in measured VO(2), HR and RPP for the increment in estimated VO(2) (absolute load) decreased similarly in all groups (combined data = -9.1 ± 2.6, -14.1 ± 3.9, -14.2 ± 3.0%, respectively, P < 0.05), while the increments in the cardiovascular variables for the increase in measured VO(2) did not change. In elderly subjects, ST and PT did not blunt submaximal or maximal HR, SBP and RPP increases during the maximal exercise test, showing that they did not reduce cardiovascular stress during aerobic tasks.

Baseline severity but not gender modulates quantified Crataegus extract effects in early heart failure – A pooled analysis of clinical trials

Objective The efficacy of quantified Crataegus extract in chronic heart failure (CHF) has been assessed in numerous clinical studies. The present pooled analysis evaluates the impact of baseline severity and gender on objective and patient-reported endpoints and associations between both types of outcomes in patients with early CHF. Methods Available data from 687 individual patients treated with quantified Crataegus extract or placebo in ten studies were pooled. Treatment effects on physiologic outcome parameters and on symptoms were analysed for their association with baseline severity and gender. Changes in symptom scores were investigated with respect to their relation to physiologic outcome parameters. Results were compared with observations in a 3-year cohort study. Results Physiologic outcome parameters maximal workload (MWL), left ventricular ejection fraction (LVEF) and pressure-heart rate product increase (PHRPI) at 50 W ergometric exercise improved more in active treatment than in placebo patients. Magnitude of improvement was independent from baseline for LVEF but increased for MWL and PHRPI with baseline severity. Improvement of typical symptoms like reduced exercise tolerance, exertional dyspnea, weakness, fatigue, and palpitations improved more with active treatment and in patients with more severe symptoms. A weak association between improvements in MWL, PRHP, and symptoms could be demonstrated. Gender differences in treatment effects could be explained by baseline differences. Results of the pooled analysis are in agreement with observations in the cohort study. Conclusions Crataegus extract treatment effects on physiologic outcomes and typical symptoms were modulated by baseline severity. Taking baseline differences into account, benefits were comparable in male and female patients with impaired exercise-tolerance in early chronic heart-failure.

Cardiovascular Workload After A Single Bout Of Resistance Exercise In Patients With Peripheral Arterial Disease

A single bout of resistance exercise decreases systolic blood pressure (SBP), suggesting that resistance exercise might be useful to reduce cardiovascular workload in peripheral arterial disease (PAD) patients. However, whether this response is accompanied by an increase in heart rate (HR) and rate pressure product (RPP) leading to an increase in cardiovascular workload remains unknown. PURPOSE. To analyze the effects of a single bout of resistance exercise on cardiovascular workload in patients with PAD. METHODS: Thirteen patients with PAD performed two experimental sessions in random order: control (C) and resistance exercise (R) sessions. Both experimental sessions were identical (six exercises, three sets of 10 repetitions), however while in the C session the intensity in all exercises was 0 in the Omni-Res scale, in the R session it was between 5-7. Before and at 10, 30 and 50 min after experimental sessions, SBP, HR, heart rate variability (HRV), and RPP were obtained. RESULTS. In comparison with pre-intervention values, SBP increased significantly after the C session during all the recovery stages (greatest increase = +10 ± 12 mmHg, P < 0.05), while it decreased significantly after the R session during all the recovery stages (greatest fall = -6±10 mmHg, P < 0.05). The changes in SBP after the R session were significantly greater than after the C session. In comparison with pre-intervention values, HR decreased significantly after the C session at all recovery stages (greatest fall = -7 ± 6 bpm, P < 0.05) and after the R session at 50 min of recovery (-3 ± 8, bpm, P < 0.05). The changes in HR after the C session were significantly greater than after the R session. After both experimental sessions the changes in HR were not enough to alter the HRV. RPP did not change significantly after both experimental sessions (P>0.05). CONCLUSION: A single bout of resistance exercise reduces SBP without increasing HR and RPP. Therefore, resistance exercise might be useful to decrease cardiovascular workload in PAD patients.

Cardiovascular Responses During Constant Load Walking in Patients with Peripheral Arterial Disease

Exaggerated increases in heart rate and blood pressure are abnormal cardiovascular responses during constant load walking in peripheral arterial disease (PAD) patients, and are markers of hemodynamic instability and increased cardiovascular risk. However, predictors of changes in heart rate and blood pressure are poorly described. Purposes. To assess the cardiovascular responses during constant load walking, and to identify predictors of this response in PAD patients. Methods. Seventy-nine patients with PAD performed a constant load treadmill test (2 mph, 0% grade). During the test, systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), and rate pressure product (RPP) were obtained at the fourth minute to the last minute of walking. Patients were also characterized on demographic measures, cardiovascular risk factors, baseline exercise performance measures, and vascular measures. Results. During constant load walking, there was a significant increase (p < 0.01) in SBP (+12 ± 10 mmHg), DBP (+6 ± 9 mmHg), HR (+5 ± 5 bpm) and RPP (+1920 ± 1435 mmHg x bpm). The HR and RPP responses were negatively correlated with ischemic window (r= -0.23 and r= -0.26, respectively; p<0.05) and positively correlated with the HR during the first minute of recovery from maximal graded exercise (r= 0.27 and r= 0.24, respectively; p<0.05). The increase in cardiovascular variables during walking was greater in subjects with higher BMI and in men (p < 0.05). Conclusion. Patients with PAD have an increased cardiovascular response during constant load walking, and these responses are greater in obese patients and in men. The clinical implication is that PAD patients engaged in walking training programs, particularly obese men, require frequent assessment of cardiovascular parameters to avoid exaggerated increases in BP, HR and RPP during constant work load walking. Funding by the following: NIA(R01-AG-24296); OCAST(HR04-1138;AWG); and GCRC(M01-RR-14467).

Changes in Cardiac Physiology After Severe Burn Injury

Cardiac stress, mediated by increased catecholamines, is the hallmark of severe burn injury typified by marked tachycardia, increased myocardial oxygen consumption, and increased cardiac output (CO). It remains one of the main determinants of survival in large burns. Currently, it is unknown for how long cardiac stress persists after a severe injury. Therefore, the aim of this study was to determine the extent and duration of cardiac stress after a severe burn. To determine persistence of cardiac alteration, the authors determined cardiac parameters of all surviving patients with burns ≥ 40% TBSA from 1998 to 2008. One hundred ninety-four patients were included in this study. Heart rate, mean arterial pressure, CO, stroke volume, cardiac index, and ejection fractions were measured at regular intervals from admission up to 2 years after injury. Rate pressure product was calculated as a correlate of myocardial oxygen consumption. All values were compared with normal nonburned children to validate the findings. Statistical analysis was performed using log transformed analysis of variance with Bonferroni correction and Student's t-test, where applicable. Heart rate, CO, cardiac index, and rate pressure product remained significantly increased in burned children for up to 2 years when compared with normal ranges (P < .05), indicating vastly increased cardiac stress. Ejection fraction was within normal limits for 2 years. Cardiac stress persists for at least 2 years postburn, and the authors suggest that attenuation of these detrimental responses may improve long-term morbidity.

The combination of l-arginine and ischaemic post-conditioning at the onset of reperfusion limits myocardial injury in the pig

To investigate whether ischaemic post-conditioning (IPoC) combined with i.v. infusion of the nitric oxide (NO) substrate L-arginine at the onset of reperfusion exerts cardioprotective effect that is superior to either treatment given separately. Twenty-six anesthetized pigs were subjected to coronary artery (left anterior descending artery, LAD) ligation for 40 min followed by 4 h reperfusion. The pigs were randomized into five different groups receiving either i.v. vehicle, i.v. L-arginine, IPoC 4 × 60 s together with i.v. vehicle or IPoC together with i.v. L-arginine and a group with IPoC 8 × 30 s. All infusions were started 10 min before reperfusion. The infarct size of the vehicle group was 82 ± 4% of the area at risk. L-Arginine alone (79 ± 8%), IPoC 4 × 60 s vehicle (86 ± 3%) or IPoC 8 × 30 s vehicle (94 ± 7%) did not affect infarct size. l-Arginine together with IPoC significantly reduced infarct size to 59 ± 4% (P < 0.01). Except for higher LAD flow during early reperfusion in the IPoC L-arginine group, haemodynamic parameters did not differ between the four main groups. Heart rate and rate pressure product were lower during ischaemia and reperfusion in the IPoC 8 × 30 s vehicle group. In comparison with the vehicle group, there were no changes in the expression of Akt, phosphorylated Akt Ser(473) , inducible NO synthase, endothelial NO synthase (eNOS) or phosphorylated eNOS Ser(1177) in the ischaemic/reperfused myocardium. L-Arginine given systemically at the onset of reperfusion protects the pig heart against ischaemia and reperfusion injury only when combined with IPoC. These results indicate that the combination of the two treatment strategies exerts cardioprotection.

A comparative study of efficacy of esmolol and fentanyl for pressure attenuation during laryngoscopy and endotracheal intubation.

Objective:To compare the effectiveness of single bolus dose of esmolol or fentanyl in attenuating the hemodynamic responses during laryngoscopy and endotracheal intubation.Methods:Ninety adult ASA I and ASA II patients were included in the study who underwent elective surgical procedures. Patients were divided into three groups. Group C (control) receiving 10 ml normal saline, group E (esmolol) receiving bolus dose of esmolol 2 mg/kg and group F (fentanyl) receiving bolus dose of fentanyl 2 µg/kg intravenously slowly. Study drug was injected 3 min before induction of anesthesia. Heart rate, systemic arterial pressure and ECG were recorded as baseline and after administration of study drug at intubation and 15 min thereafter.Results:Reading of heart rate, blood pressure and rate pressure product were compared with baseline and among each group. The rise in heart rate was minimal in esmolol group and was highly significant. Also the rate pressure product at the time of intubation was minimal and was statistically significant rate 15 min thereafter in group E.Conclusion:Esmolol 2 mg/kg as a bolus done proved to be effective in attenuating rises in heart rate following laryngoscopy and intubation while the rise in blood pressure was suppressed but not abolished by bolus dose of esmolol.

Hemodynamic variables during exercise in childhood and resting systolic blood pressure levels 6 years later in adolescence: the European Youth Heart Study

The aim of this study was to analyze whether systolic blood pressure (SBP), heart rate (HR) and rate pressure product (RPP) during exercise in childhood can predict resting SBP levels in adolescence independent of resting SBP and conventional cardiovascular risk factors. We studied this in a sample of Danish children followed longitudinally for 6 years. The study comprised 226 children randomly sampled at age 9, who had their blood pressure and HR measured during ergometer exercise to exhaustion and was reassessed in adolescence. SBP and RPP during exercise in stage two of the test were positively associated with future resting SBP, independent of resting SBP in childhood (P=0.045 and P=0.013, respectively). After additional adjustment for conventional cardiovascular risk factors the associations with SBP and RPP during stage two on future resting SBP only slightly materially change, although only RPP remained significant (P=0.059 and P=0.012, respectively). No significant independent associations were observed for HR during exercise, but associations were in the same direction. Our results supports that measuring SBP and RPP, during a standard acute ergometer exercise test in children, improves the prediction of future SBP levels during rest in adolescence independent of resting SBP and conventional cardiovascular risk factors.

An Analysis of Prospective Risk Factors for Aortic Stiffness in Men

Arterial stiffness is an important determinant of cardiovascular risk. The precise risk factors for arterial stiffening remain unclear. We aimed to identify potential risk factors using prospective exposure data from the Caerphilly Prospective Study. Aortic pulse wave velocity and augmentation index were measured in 825 men and related to current (2004) and baseline (1979-1988) anthropometric, hemodynamic, and biochemical factors. The mean age of the men was 74 years, with an average follow-up of 20 years. The only independent baseline predictors of current velocity were pulse pressure (standardized beta-coefficient: 0.58), C-reactive protein (0.35), glucose (0.25), and waist circumference (0.23). The sole baseline predictor of current augmentation index was fibrinogen (0.78). After additional adjustment for the corresponding current risk factor, pulse wave velocity was best related to cumulative exposure to C-reactive protein, whereas augmentation index was most strongly related to current levels. Velocity was also more strongly correlated with baseline levels of triglycerides and smoking but with current waist circumference. The pulse pressure heart rate product assessed over the whole of 20 years was independently correlated with aortic pulse wave velocity but not augmentation index. Other than blood pressure, established cardiovascular risk factors have only a modest effect on aortic stiffness and wave reflection. Inflammation and the level of repetitive cyclic stress are important predictors of aortic stiffness, whereas wave reflection is predicted by acute inflammation only. Adequate control of pulse pressure and heart rate, as well as reducing inflammation, may, in the long-term, retard aortic stiffening, although this remains to be tested directly.

Effect of Resistance Training and Aerobic Conditioning on Muscular Strength and Submaximal Fitness for Individuals with Chronic Heart Failure: Influence of Age and Gender

The hallmark characteristic of chronic heart failure (CHF) is exercise intolerance. This study evaluated a combined exercise program that would be consistent with current cardiac rehabilitation guidelines. The program consisted of progressive resistance training (intensity progressing from 50 to 80% maximum) and aerobic conditioning (70% of heart rate reserve). Outcomes included muscular strength measured as 8-repetition maximum and submaximal aerobic fitness indicators (measured at 50% of predicted maximal oxygen consumption) including heart rate, blood pressure, and rate pressure product. Subjects were taken retrospectively from a database of CHF patients who underwent cardiac rehabilitation between 1998 and 2004 with the Cardiac Rehabilitation Center of River Cities Cardiology in Jeffersonville, IN. The same data set was used to evaluate 2 research questions: to compare training outcomes between gender (men and women) and to compare outcomes between young (<or=65 years) and old (>65 years) subjects. Forty-two subjects (15 women and 27 men; 19 were <or=65 and 23 were >65 years of age) met inclusion and exclusion criteria and underwent 36 sessions of cardiac rehabilitation over a 14-week time period. Repeated-measures analysis of variance was used to test whether strength and submaximal responses differed across gender or age. Analysis indicated that regardless of gender or age, subjects significantly increased their strength on each of 6 strength tests. Heart rate, systolic blood pressure, and rate pressure product were lower after training indicating increased aerobic efficiency. Progressive resistance training and aerobic conditioning prescribed in a manner consistent with cardiac rehabilitation guidelines resulted in similar improvements regardless of gender or age for individuals with CHF suggesting that no training program adjustments are necessary to accommodate age or gender.

Job Demand and Cardiovascular Disease Risk Factor in White-collar Workers

This study was conducted to determine whether job demand played a role as a risk factor of cardiovascular diseases by comparing changes of blood pressure, heart rate and rate pressure product (RPP) showing myocardial oxygen consumption (MVO2) according to levels of job demand. This cross-sectional study divided 177 male white-collar workers without a cardiovascular or metabolic disease according to their job demand and analyzed their body composition and results of graded exercise testing. There was no significant difference in height, body weight, body mass index (BMI), waist to hip ratio (WHR) and body fat percentage according to job demand. Maximal oxygen consumption (VO2max) and anaerobic threshold (AT) also did not show a significant difference. However, systolic blood pressures at the seventh and eighth stages over AT during exercise were significantly different and RPP was found to have a significant difference overall according to the job demand (p<0.05). These results meant that job demand affected systolic pressure in physical activities or at exercise intensity over AT and reduced energy efficiency of myocardium during physical activities. The results suggest that high job demand may be a risk factor of cardiovascular diseases.

Effect of occupational stress on ambulatory blood pressure

To explore the effect of occupational stress on ambulatory blood pressure. 30 male healthy workers from the refrigerator assembly line in Henan province in China were investigated. Psychosocial work conditions were measured by using the Job Demand-control Model, the Effort-reward Imbalance Model questionnaires and Occupational Stress Measurement Scale. Ambulatory blood pressure(ABP) was measured by using mobile ABP monitor. The t test was utilized to analyze the difference of parameters of ABP monitoring between different groups of occupational stress and other variables scores. The stepwise regression analysis was used to analyse the effect of occupational stress factors on parameters of ABP. (1) As to stressors, systolic blood pressure variability (SBPV), mean arterial blood pressure variability (MABPV) and heart rate at 30 minute after work in workers with high role conflict score were significantly higher than those in workers with low score (P < 0.05). Workers with high skill utilization score had significantly lower mean systolic blood pressure (SBP) at 30 minute after work than workers with low score (P < 0.05). Diastolic blood pressure variability (DBPV) and heart rate variability (HRV) in workers with high decision latitude score were significantly higher than those in workers with low score (P < 0.05). Workers with high job psychological demands score had significantly higher SBPV, DBPV and MABPV than workers with low score (P < 0.05). Heart rate-pressure product(RPP) and SBPV in workers with high effort score were significantly higher than those in workers with low score (P < 0.05). Workers with low rewards score had higher mean heart rate and heart rate at 30 minute after work than workers with high score (P < 0.05). (2) For personalities, workers with high work locus of control score had significantly higher mean diastolic blood pressure (DBP) and mean arterial blood pressure (MABP) than workers with low score (P < 0.05). Workers with high patience score had significantly lower mean SBP at 30 minute after work than workers with low score (P < 0.05). Heart rate at 30 minute after work in workers with high organization commitment score was significantly lower than that in workers with low score (P < 0.05). (3) Concerning buffer factors, HRV in workers with high control strategies score were significantly lower than that in workers with low score (P < 0.05). Workers with low supervisor support score had higher RPP and MABPV than workers with high score (P < 0.05). (4) In the multiple stepwise regression, daily life stress affected SBPV (R2 = 0.12) and MABPV (R2 = 0.05), depression was related to DBPV at 30 minute after work (R2 = 0.15) and SBPV (R = 0.03), mental health was predictor of MABPV (R2 = 0.07) and negative affection was predictor of heart rate at 30 minute after work (R2 = 0.24). Occupational stressors, personality and social support have effect on parameters of ABP. Parameters of ABP monitoring could be used to evaluate occupational stress in the field research.

Adenosine monophosphate-activated protein kinase activation, substrate transporter translocation, and metabolism in the contracting hyperthyroid rat heart.

Thyroid hormones can modify cardiac metabolism via multiple molecular mechanisms, yet their integrated effect on overall substrate metabolism is poorly understood. Here we determined the effect of hyperthyroidism on substrate metabolism in the isolated, perfused, contracting rat heart. Male Wistar rats were injected for 7 d with T(3) (0.2 mg/kg x d ip). Plasma free fatty acids increased by 97%, heart weights increased by 33%, and cardiac rate pressure product, an indicator of contractile function, increased by 33% in hyperthyroid rats. Insulin-stimulated glycolytic rates and lactate efflux rates were increased by 33% in hyperthyroid rat hearts, mediated by an increased insulin-stimulated translocation of the glucose transporter GLUT4 to the sarcolemma. This was accompanied by a 70% increase in phosphorylated AMP-activated protein kinase (AMPK) and a 100% increase in phosphorylated acetyl CoA carboxylase, confirming downstream signaling from AMPK. Fatty acid oxidation rates increased in direct proportion to the increased heart weight and rate pressure product in the hyperthyroid heart, mediated by synchronized changes in mitochondrial enzymes and respiration. Protein levels of the fatty acid transporter, fatty acid translocase (FAT/CD36), were reduced by 24% but were accompanied by a 19% increase in the sarcolemmal content of fatty acid transport protein 1 (FATP1). Thus, the relationship between fatty acid metabolism, cardiac mass, and contractile function was maintained in the hyperthyroid heart, associated with a sarcolemmal reorganization of fatty acid transporters. The combined effects of T(3)-induced AMPK activation and insulin stimulation were associated with increased sarcolemmal GLUT4 localization and glycolytic flux in the hyperthyroid heart.

Morning blood pressure, heart rate, pulse pressure and rate pressure product in male hypertensives according to ageing

Morning blood pressure, heart rate, pulse pressure and rate pressure product in male hypertensives according to ageing