Effect of an increase in coronary perfusion on transmural ventricular repolarization

Summary The effect of increased coronary flow on transmural ventricular repolarization was investigated in 6 pentobabital-anaesthetised sheep. The left circumflex coronary artery (LCX) was injected with fresh blood at 10 ml/min in addition to the normal coronary flow. Unipolar electrocardiograms were simultaneously registered from epicardium, midmyocardium and endocardium with fine plunge needles. Activation-recovery interval (ARI) was measured from the unipolar electrocardiograms and was used as an estimate of ventricular repolarization duration. It was found that intracoronary blood injectio

Editor-in-Chief JEPonline The Effect of 24 Weeks of Moderate Intensity Walking upon Metabolic Syndrome Risk Factors in Previously Sedentary/Low Active Men

ABSTRACT , respectively). The post-intervention changes: insulin correlated with WC (R=0.441; P<0.002); ISI negatively with WC (R= -0.433; P<0.003), indicating the changes in body composition to have affected insulin metabolism and insulin sensitivity. The men who walked at an easily attainable intensity for most mobile adults of ~51% of relative VO 2 max showed reduced WC and enhanced insulin sensitivity, thus reducing their risk of MetS and type II diabetes

Editor-in-Chief Editor-in-Chief JEPonline Increasing Physical Activity Decreases Hepatic Fat and Metabolic Risk Factors

ABSTRACT Alderete TL, Gyllenhammer LE, Byrd-Williams CE, Spruijt-Metz D, Goran MI, Davis JN. Increasing Physical Activity Decreases Hepatic Fat and Metabolic Risk Factors. JEPonline 2012;15(2):40-54. This study assessed the changes in time spent in moderate to vigorous physical activity (MVPA) on fat depots, insulin action, and inflammation. Longitudinal data were generated from 66 Hispanic adolescents (15.6±1.1 yr; BMI percentile 97.1±3.0) who participated in a 16-wk nutrition or nutrition+exercise intervention. There were no effects of the intervention on PA, but there were inter-individual changes in PA. For purposes of this analysis, all intervention groups were combined to assess how changes in PA during 16 wk affected changes in adiposity, insulin action, and markers of inflammation. MVPA was assessed by 7-day accelerometry, total body fat via DXA, liver fat by MRI, and insulin, glucose and HOMA-IR via a fasting blood draw. A repeated measures ANCOVA was used to assess the effect of MVPA on fat depots, insulin action, and inflammatory markers. Sixty-two percent of participants increased MVPA (mean increase, 19.7±16.5 min/day) and 38% decreased MVPA (mean decrease, 10.7±10.1 min/day). Those who increased MVPA by as little as 20 min per day over 16 wk, compared to those who decreased MVPA, had significant reductions in liver fat (-13% vs. +3%; P=0.01), leptin levels (-18% vs. +4%; P=0.02), and fasting insulin (-23% vs. +5%; P=0.05). These findings indicate that a modest increase in MVPA can improve metabolic health in sedentary overweight Hispanic adolescents

Editor-in-Chief Editor-in-Chief JEPonline Influence of the I/D Polymorphism of the Angiotensin Converting Enzyme Gene and Acute Aerobic Exercise in the Ambulatory Arterial Stiffness Index of Elderly Women

ABSTRACT (5) :1-9. Acute bouts of exercise can reduce arterial stiffness in elderly, but the effect of exercise seems to be influenced by genetic factors. The aim of this study was to verify the influence of the angiotensin converting enzyme (ACE) gene's insertion/deletion polymorphism and acute aerobic exercise in the ambulatory arterial stiffness index (AASI) of elderly women. Twenty-five elderly women (70.9 ± 6.1 yrs; 25.2 ± 2.7 kg/m 2 ), previously genotyped for the ACE gene's I/D polymorphism, participated in this study. The volunteers were submitted to an incremental test to identify anaerobic threshold (AT). Afterwards, they underwent two sessions: a 90% AT Session and a Control Session. The AASI was measured during the 24 hrs after the sessions. In conclusion, exercise performed at 90% AT reduced arterial stiffness of the elderly subjects', especially carriers of the D/D ACE gene genotype

Journal of Exercise Physiologyonline JEPonline The Effects of Resistance Training Frequency on Strength Gains

ABSTRACT Serra R, Saavedra F, De Salles BF, Dias MR, Costa P, Alves H, Simão R. Effects of Resistance Training Frequency on Strength Gains. JEPonline 2015;18(1):37-45. The purpose of the present study was to compare the effects of different training frequencies on strength gains in untrained males after 8 months of resistance training. Forty-five middle-age men were randomly assigned to one of 3 training groups: 2 (G2; n = 18), 3 (G3; n = 17), and 4 sessions·week -1 (G4; n = 10). Each group performed the same resistance training program with the exception of the training frequency. The 10RM tests were conducted in 2 nonconsecutive sessions for the bench press, leg press, and lat pulldown exercises at baseline, and after 4 and 8 months following resistance training. All three groups showed significant increases in 10RM loads for all exercises (P<0.05). The findings of this study indicate that 2 to 4 weekly training sessions produce significant strength gains. Thus, lower frequencies may be all that is necessary for individuals with short time to increase adherence and strength gains in untrained males

Editor-in-Chief Systems Physiology-Cardiopulmonary EFFECTS OF CHRONIC SWIMMING ON BLOOD PRESSURE AND SODIUM PUMP OF HYPERTENSIVE RATS

ABSTRACT Osiecki R, Malfatti CRM, Royes LFF, Sampedro RMF, Mello CF. Effects of chronic swimming on blood pressure and sodium pump of hypertensive rats. JEPonline 2008;11(5):35-41. In this study we investigated whether chronic exercise alters erythrocyte Na + ,K + -ATPase activity and hemodynamical parameters in adult male spontaneously hypertensive rats (SHR). Animals were randomly assigned to trained (n= 8) and untrained (n= 8) groups. Training was conducted 6 days/week for 12 weeks, alternating 60 and 90 min swimming sessions daily. At the end of the training program, animals underwent a 90 min swimming challenge and blood lactate was measured. Twenty hours after the challenge, a cannula was introduced into the right carotid artery for direct recording of the blood pressure and heart rate. After obtaining hemodynamical measures, blood was collected for erythrocyte Na + ,K + -ATPase activity. Training significantly reduced systolic (-9.2 %; p<0.01), diastolic (-13.3 %; p<0.01), mean blood pressure ( -11.3 %; p<0.001), resting heart rate (-14.5 %; p<0.001), plasma lactate levels (-44.8%; p<0.05) and a higher erythrocyte Na + ,K + -ATPase activity (41.5 % ; p<0.05). It is suggested that the exercise-induced increase of erythrocyte Na + ,K + -ATPase activity may contribute to decreased blood pressure

Editor-in-Chief JEPonline The Marc Pro TM Device Improves Muscle Performance and Recovery from Concentric and Eccentric Exercise Induced Muscle Fatigue in Humans: A Pilot Study

Exercise Induced Muscle Fatigue in Humans: A Pilot Study. JEPonline 2011;14(2):55-67. To date, a product or routine that consistently relieves delayed onset muscle soreness (DOMS) caused by eccentric exercise has yet to be identified. Our latest 56 research results indicate that a new device called Marc Pro™ (MPD) significantly improves muscle recovery and muscle endurance from combined concentric and eccentric exercise in healthy recreational exercisers. In the first study, 14 subjects (no prior soreness upon study entry) performed strength training activity (leg extension exercise with eccentric emphasis) to produce DOMS in the quadriceps muscles. All participants received one-hour of MPD stimulation on the right leg only following the exercise session whereby each participant served as their own control. One day later, assessment of muscle soreness revealed significantly less discomfort in the right leg (MPD) than in the left leg (no MPD) in all subjects and in responders, respectively (p < 0.008; p < 0.002 ). The number of repetitions completed with the right leg (MPD) was significantly greater than the number of repetitions completed with the left leg (no MPD) in all subjects and in responders, respectively (p < 0.03; p < 0.008). In the second experiment, 13 subjects (no prior soreness upon study entry) utilized a modestly challenging uphill/downhill hike to produce DOMS in the quadriceps muscles. Following the hike the subjects' right leg received MPD stimulation for 60 minutes, whereas the left leg received no MPD application. Reported soreness was significantly less in the right leg (MPD) than in the left leg (no MPD) in all participants and in responders, respectively (p < 0.0008; p < 0.0002). These results suggest that MPD stimulation results in a significant reduction in DOMS following strenuous unaccustomed eccentric exercise and significantly greater muscle endurance performance, as measured by leg extension repetitions. Investigation of Marc Pro TM in a larger population is underway and must await confirmation

Adiposity and risk of ischaemic and haemorrhagic stroke in 0·5 million Chinese men and women: a prospective cohort study

Summary: Background: China has high stroke rates despite the population being relatively lean. Uncertainty persists about the relevance of adiposity to risk of stroke types. We aimed to assess the associations of adiposity with incidence of stroke types and effect mediation by blood pressure in Chinese men and women. Methods: The China Kadoorie Biobank enrolled 512 891 adults aged 30–79 years from ten areas (five urban and five rural) during 2004–08. During a median 9 years (IQR 8–10) of follow-up, 32 448 strokes (about 90% confirmed by neuroimaging) were recorded among 489 301 participants without previous cardiovascular disease. Cox regression analysis was used to produce adjusted hazard ratios (HRs) for ischaemic stroke (n=25 210) and intracerebral haemorrhage (n=5380) associated with adiposity. Findings: Mean baseline body-mass index (BMI) was 23·6 kg/m2 (SD 3·2), and 331 723 (67·8%) participants had a BMI of less than 25 kg/m2. Throughout the range examined (mean 17·1 kg/m2 [SD 0·9] to 31·7 kg/m2 [2·0]), each 5 kg/m2 higher BMI was associated with 8·3 mm Hg (SE 0·04) higher systolic blood pressure. BMI was positively associated with ischaemic stroke, with an HR of 1·30 (95% CI 1·28–1·33 per 5 kg/m2 higher BMI), which was generally consistent with that predicted by equivalent differences in systolic blood pressure (1·25 [1·24–1·26]). The HR for intracerebral haemorrhage (1·11 [1·07–1·16] per 5 kg/m2 higher BMI) was less extreme, and much weaker than that predicted by the corresponding difference in systolic blood pressure (1·48 [1·46–1·50]). Other adiposity measures showed similar associations with stroke types. After adjustment for usual systolic blood pressure, the positive associations with ischaemic stroke were attenuated (1·05 [1·03–1·07] per 5 kg/m2 higher BMI); for intracerebral haemorrhage, they were reversed (0·73 [0·70–0·77]). High adiposity (BMI >23 kg/m2) accounted for 14·7% of total stroke (16·5% of ischaemic stroke and 6·7% of intracerebral haemorrhage). Interpretation: In Chinese adults, adiposity was strongly positively associated with ischaemic stroke, chiefly through its effect on blood pressure. For intracerebral haemorrhage, leanness, either per se or through some other factor (or factors), might increase risk, offsetting the protective effects of lower blood pressure. Funding: UK Wellcome Trust, UK Medical Research Council, British Heart Foundation, Cancer Research UK, Kadoorie Charitable Foundation, Chinese Ministry of Science and Technology, Chinese National Natural Science Foundation

Age-specific association between blood pressure and vascular and non-vascular chronic diseases in 0·5 million adults in China: a prospective cohort study

Summary: Background: The age-specific association between blood pressure and vascular disease has been studied mostly in high-income countries, and before the widespread use of brain imaging for diagnosis of the main stroke types (ischaemic stroke and intracerebral haemorrhage). We aimed to investigate this relationship among adults in China. Methods: 512 891 adults (59% women) aged 30–79 years were recruited into a prospective study from ten areas of China between June 25, 2004, and July 15, 2008. Participants attended assessment centres where they were interviewed about demographic and lifestyle characteristics, and their blood pressure, height, and weight were measured. Incident disease was identified through linkage to local mortality records, chronic disease registries, and claims to the national health insurance system. We used Cox regression analysis to produce adjusted hazard ratios (HRs) relating systolic blood pressure to disease incidence. HRs were corrected for regression dilution to estimate associations with long-term average (usual) systolic blood pressure. Findings: During a median follow-up of 9 years (IQR 8–10), there were 88 105 incident vascular and non-vascular chronic disease events (about 90% of strokes events were diagnosed using brain imaging). At ages 40–79 years (mean age at event 64 years [SD 9]), usual systolic blood pressure was continuously and positively associated with incident major vascular disease throughout the range 120–180 mm Hg: each 10 mm Hg higher usual systolic blood pressure was associated with an approximately 30% higher risk of ischaemic heart disease (HR 1·31 [95% CI 1·28–1·34]) and ischaemic stroke (1·30 [1·29–1·31]), but the association with intracerebral haemorrhage was about twice as steep (1·68 [1·65–1·71]). HRs for vascular disease were twice as steep at ages 40–49 years than at ages 70–79 years. Usual systolic blood pressure was also positively associated with incident chronic kidney disease (1·40 [1·35–1·44]) and diabetes (1·14 [1·12–1·15]). About half of all vascular deaths in China were attributable to elevated blood pressure (ie, systolic blood pressure >120 mm Hg), accounting for approximately 1 million deaths (<80 years of age) annually. Interpretation: Among adults in China, systolic blood pressure was continuously related to major vascular disease with no evidence of a threshold down to 120 mm Hg. Unlike previous studies in high-income countries, blood pressure was more strongly associated with intracerebral haemorrhage than with ischaemic stroke. Even small reductions in mean blood pressure at a population level could be expected to have a major impact on vascular morbidity and mortality. Funding: UK Wellcome Trust, UK Medical Research Council, British Heart Foundation, Cancer Research UK, Kadoorie Charitable Foundation, Chinese Ministry of Science and Technology, and the National Science Foundation of China

Maternal and neonatal outcomes after caesarean delivery in the African Surgical Outcomes Study: a 7-day prospective observational cohort study.

BACKGROUND: Maternal and neonatal mortality is high in Africa, but few large, prospective studies have been done to investigate the risk factors associated with these poor maternal and neonatal outcomes. METHODS: A 7-day, international, prospective, observational cohort study was done in patients having caesarean delivery in 183 hospitals across 22 countries in Africa. The inclusion criteria were all consecutive patients (aged ≥18 years) admitted to participating centres having elective and non-elective caesarean delivery during the 7-day study cohort period. To ensure a representative sample, each hospital had to provide data for 90% of the eligible patients during the recruitment week. The primary outcome was in-hospital maternal mortality and complications, which were assessed by local investigators. The study was registered on the South African National Health Research Database, number KZ_2015RP7_22, and on ClinicalTrials.gov, number NCT03044899. FINDINGS: Between February, 2016, and May, 2016, 3792 patients were recruited from hospitals across Africa. 3685 were included in the postoperative complications analysis (107 missing data) and 3684 were included in the maternal mortality analysis (108 missing data). These hospitals had a combined number of specialist surgeons, obstetricians, and anaesthetists totalling 0·7 per 100 000 population (IQR 0·2-2·0). Maternal mortality was 20 (0·5%) of 3684 patients (95% CI 0·3-0·8). Complications occurred in 633 (17·4%) of 3636 mothers (16·2-18·6), which were predominantly severe intraoperative and postoperative bleeding (136 [3·8%] of 3612 mothers). Maternal mortality was independently associated with a preoperative presentation of placenta praevia, placental abruption, ruptured uterus, antepartum haemorrhage (odds ratio 4·47 [95% CI 1·46-13·65]), and perioperative severe obstetric haemorrhage (5·87 [1·99-17·34]) or anaesthesia complications (11·47 (1·20-109·20]). Neonatal mortality was 153 (4·4%) of 3506 infants (95% CI 3·7-5·0). INTERPRETATION: Maternal mortality after caesarean delivery in Africa is 50 times higher than that of high-income countries and is driven by peripartum haemorrhage and anaesthesia complications. Neonatal mortality is double the global average. Early identification and appropriate management of mothers at risk of peripartum haemorrhage might improve maternal and neonatal outcomes in Africa. FUNDING: Medical Research Council of South Africa.Medical Research Council of South Africa