Rapid communication : effect of exercise training on asymmetric dimethylarginine concentration in women aged 65-74 years with type 2 diabetes

Aims/hypothesis: Basal plasma concentration of asymmetric dimethylarginine (ADMA), an endogenous, competitive inhibitor of nitric oxide synthase, is elevated in patients with type 2 diabetes. ADMA may contribute to the endothelial dysfunction and associated vascular complications observed in individuals with type 2 diabetes. The present study investigated the effect of 12 weeks of supervised walking exercise on plasma ADMA concentration in women aged 65-74 years with type 2 diabetes. Materials and methods: Fourteen women (aged 69 ± 3 yrs) with uncomplicated type 2 diabetes, completed 12 weeks of supervised, moderate-intensity walking at an intensity equivalent to their individual gas-exchange threshold. Blood was sampled for ADMA concentration before and after a 6-week intervention-free control period, and again after 6 and 12 weeks of exercise training. Results: Plasma ADMA concentration was found to be significantly lower after 12-weeks of exercise training when compared with baseline (0 wk) measurements. These results were accompanied by significant increases in time to exhaustion, relative and absolute peak oxygen uptake, and oxygen uptake at gas-exchange threshold. Conclusion/interpretation: Regular, moderate-intensity exercise decreases circulating ADMA concentrations in older women with type 2 diabetes. These results suggest that ADMA may play a role in the training-induced reduction in cardiovascular disease risk seen with exercise training in individuals with type 2 Diabetes

The potential of anthocyanin-rich Queen Garnet plum juice supplementation in alleviating thrombotic risk under induced oxidative stress conditions

Increased oxidant production in humans induces a number of thrombotic consequences; including platelet hyperactivity/aggregability, which could be countered through specifically developed functional foods. We sought to determine the antithrombotic properties of anthocyanin-rich Queen Garnet plum juice (QGPJ) supplementation with and without exercise-induced oxidative stress. Thirteen healthy participants were investigated in a randomised, double-blind, placebo controlled, cross-over trial. Participants consumed 200 mL/day of QGPJ and placebo juice for 28-days, with treatments separated by a two-week wash-out period. Blood samples were collected at baseline and after 1 h of exercise (70% peak-O2 uptake) both before and after oral supplementation and evaluated for platelet function and haemostatic activity. QGPJ supplementation inhibited adenosine diphosphate-induced platelet aggregation both without and under exercise induced oxidative stress by 10.7% (P < 0.01) and 12.7% (P < 0.001) respectively; arachidonic acid-induced aggregation under oxidative stress by 28.8% (P < 0.05); reduced platelet activation dependant P-selectin expression by 32.9% (P < 0.01) and 38.7% (P < 0.001) both without and under oxidative stress respectively; and exhibited favourable effects on coagulation parameters both with and without oxidative stress. The anti-thrombotic activity exhibited byanthocyanin-rich QGPJ suggests a potential for cardiovascular disease risk reduction and may be considered as complementary anti-platelet nutritional therapy in pro-thrombotic population

Heart rate variability is related to impaired haemorheology in older women with type 2 diabetes

Impaired heart rate variability (HRV) and haemorheology are independently associated with cardiovascular disease and diabetic complications. The aim of the present study was to investigate the relationships between parameters of HRV, and red blood cell (RBC) aggregation and deformability, in older women with type 2 diabetes. Twenty women (age 69±2 yr) with uncomplicated type 2 diabetes and twenty controls (age 69±3 yr) participated in the study. Beat-to-beat cardiac (RR) intervals over 5 min were analysed for HRV parameters in the time and frequency domains. Blood was sampled for RBC deformability, as well as RBC aggregation in two suspending mediums: haematocrit adjusted plasma and 3% dextran 70. RBC aggregation was increased and HRV was impaired for those with type 2 diabetes when compared with control. RBC aggregation was negatively related to low frequency power of HRV, and was positively related to high frequency power of HRV, for subjects with type 2 diabetes. RBC deformability was positively related to HRV only for those with type 2 diabetes. Impaired haemorheology is associated with reduced HRV in older women with type 2 diabetes, suggesting changes in the microcirculation may result in impaired modulation of cardiac cycles

Heart rate variability is related to impaired haemorheology in older women with type 2 diabetes

Impaired heart rate variability (HRV) and haemorheology are independently associated with cardiovascular disease and diabetic complications. The aim of the present study was to investigate the relationships between parameters of HRV, and red blood cell (RBC) aggregation and deformability, in older women with type 2 diabetes. Twenty women (age 69±2 yr) with uncomplicated type 2 diabetes and twenty controls (age 69±3 yr) participated in the study. Beat-to-beat cardiac (RR) intervals over 5 min were analysed for HRV parameters in the time and frequency domains. Blood was sampled for RBC deformability, as well as RBC aggregation in two suspending mediums: haematocrit adjusted plasma and 3% dextran 70. RBC aggregation was increased and HRV was impaired for those with type 2 diabetes when compared with control. RBC aggregation was negatively related to low frequency power of HRV, and was positively related to high frequency power of HRV, for subjects with type 2 diabetes. RBC deformability was positively related to HRV only for those with type 2 diabetes. Impaired haemorheology is associated with reduced HRV in older women with type 2 diabetes, suggesting changes in the microcirculation may result in impaired modulation of cardiac cycles

Fixed-intensity exercise tests to measure exertional dyspnoea in chronic heart and lung populations: a systematic review

Introduction Exertional dyspnoea is the primary diagnostic symptom for chronic cardiopulmonary disease populations. Whilst a number of exercise tests are used, there remains no gold standard clinical measure of exertional dyspnoea. The aim of this review was to comprehensively describe and evaluate all types of fixed-intensity exercise tests used to assess exertional dyspnoea in chronic cardiopulmonary populations and, where possible, report the reliability and responsiveness of the tests. Methods A systematic search of five electronic databases identified papers that examined 1) fixed-intensity exercise tests and measured exertional dyspnoea, 2) chronic cardiopulmonary populations, 3) exertional dyspnoea reported at isotime or upon completion of fixed-duration exercise tests, and 4) published in English. Results Searches identified 8785 papers. 123 papers were included, covering exercise tests using a variety of fixed-intensity protocols. Three modes were identified, as follows: 1) cycling (n=87), 2) walking (n=31) and 3) other (step test (n=8) and arm exercise (n=2)). Most studies (98%) were performed on chronic respiratory disease patients. Nearly all studies (88%) used an incremental exercise test. 34% of studies used a fixed duration for the exercise test, with the remaining 66% using an exhaustion protocol recording exertional dyspnoea at isotime. Exertional dyspnoea was measured using the Borg scale (89%). 7% of studies reported reliability. Most studies (72%) examined the change in exertional dyspnoea in response to different interventions. Conclusion Considerable methodological variety of fixed-intensity exercise tests exists to assess exertional dyspnoea and most test protocols require incremental exercise tests. There does not appear to be a simple, universal test for measuring exertional dyspnoea in the clinical setting