Food readjustment plus exercise training improves cardiovascular autonomic control and baroreflex sensitivity in high-fat diet-fed ovariectomized mice.

Despite consensus on the benefits of food readjustment and/or moderate-intensity continuous exercise in the treatment of cardiometabolic risk factors, there is little evidence of the association between these two cardiovascular risk management strategies after menopause. Thus, the objective of this study was to evaluate the effects of food readjustment and/or exercise training on metabolic, hemodynamic, autonomic, and inflammatory parameters in a model of loss of ovarian function with diet-induced obesity. Forty C57BL/6J ovariectomized mice were divided into the following groups: high-fat diet-fed - 60% lipids throughout the protocol (HF), food readjustment - 60% lipids for 5 weeks, readjusted to 10% for the next 5 weeks (FR), high-fat diet-fed undergoing moderate-intensity exercise training (HFT), and food readjustment associated with moderate-intensity exercise training (FRT). Blood glucose evaluations and oral glucose tolerance tests were performed. Blood pressure was assessed by direct intra-arterial measurement. Baroreflex sensitivity was tested using heart rate phenylephrine and sodium nitroprusside induced blood pressure changes. Cardiovascular autonomic modulation was evaluated in time and frequency domains. Inflammatory profile was evaluated by IL-6, IL-10 cytokines, and TNF-alpha measurements. Only the exercise training associated with food readjustment strategy induced improved functional capacity, body composition, metabolic parameters, inflammatory profile, and resting bradycardia, while positively changing cardiovascular autonomic modulation and increasing baroreflex sensitivity. Our findings demonstrate that the association of these strategies seems to be effective in the management of cardiometabolic risk in a model of loss of ovarian function with diet-induced obesity.

Combined training is the most effective training modality to improve aerobic capacity and blood pressure control in people requiring haemodialysis for end-stage renal disease: systematic review and network meta-analysis.

QUESTIONS: Do aerobic, resistance and combined exercise training improve aerobic capacity, arterial blood pressure and haemodialysis efficiency in people requiring haemodialysis for end-stage renal disease? Is one exercise training modality better than the others for improving these outcomes? DESIGN: Systematic review with network meta-analysis of randomised trials. PARTICIPANTS: Adults requiring haemodialysis for end-stage renal disease. INTERVENTION: Aerobic training, resistance training, combined training and control (no exercise or placebo). OUTCOME MEASURES: Aerobic capacity, arterial blood pressure at rest, and haemodialysis efficiency. RESULTS: Thirty-three trials involving 1254 participants were included. Direct meta-analyses were conducted first. Aerobic capacity improved significantly more with aerobic training (3.35 ml/kg/min, 95% CI 1.79 to 4.91) and combined training (5.00 ml/kg/min, 95% CI 3.50 to 6.50) than with control. Only combined training significantly reduced systolic (-9 mmHg, 95% CI -13 to -4) and diastolic (-5 mmHg, 95% CI -6 to -3) blood pressure compared to control. Only aerobic training was superior to control for haemodialysis efficiency (Kt/V 0.11, 95% CI 0.02 to 0.20). However, when network meta-analysis was conducted, there were some important different findings. Both aerobic training and combined training again elicited greater improvements in aerobic capacity than control. For systolic blood pressure, combined training was superior to control. For diastolic blood pressure, combined training was superior to aerobic training and control. No modality was superior to control for haemodialysis efficiency. Combined training was ranked as the most effective treatment for aerobic capacity and arterial blood pressure. CONCLUSION: Combined training was the most effective modality to increase aerobic capacity and blood pressure control in people who require haemodialysis. This finding helps to fill the gap created by the lack of head-to-head comparisons of different modalities of exercise in people with end-stage renal disease. REGISTRATION: PROSPERO CRD42015020531.

Erratum: Interval and continuous aerobic exercise training similarly increase cardiac function and autonomic modulation in infarcted mice.

[This corrects the article on p. 257 in vol. 13, PMID: 28702435.].

Interval and continuous aerobic exercise training similarly increase cardiac function and autonomic modulation in infarcted mice.

The present study aimed to compare the effects of moderate-intensity continuous and high-intensity interval exercise training (ET) on exercise tolerance, cardiac morphometry and function, hemodynamic, and cardiac autonomic modulation in myocardial infarcted mice. Wild-type mice (WT) were divided into four groups: sedentary WT (S); WT myocardium infarction sedentary (IS); WT myocardium infarction underwent to moderate-intensity continuous ET (MICT), and WT myocardium infarction underwent to high-intensity interval ET (MIIT). After 60 days of descending coronary artery ligation, moderate-intensity continuous ET consisted of running at 60% of maximum, while the high-intensity interval training consisted of eight sprints of 4 min at 80% of maximum and a 4-min recovery at 40% of maximum. Both exercises were performed 1 hr a day, 5 days a week, during 8 weeks. Results demonstrated that IS showed elevated exercise tolerance, as well as decreased hemodynamic and heart function, and autonomic control. On the other hand, both programs of ET were equally effective to increase all parameters, without further differences between the groups. In conclusion, the results of the present study showed that myocardial infarction leads to damage in both investigated strains and the two types of physical exercise attenuated the major impairments provoked by myocardial infarction in exercise tolerance, cardiac structure, cardiac function, hemodynamic and cardiac autonomic modulation.

Cardiovascular autonomic dysfunction in non-obese diabetic mice.

It is known that diabetes is associated with autonomic dysfunction; however, data about autonomic function in non-obese diabetic mice (NOD) remain scarce. We evaluated the autonomic profile of NOD mice. Female mice, 24-28 week old, were divided in two groups: NOD (n = 6) and control (n = 6, Swiss mice). NOD mice with glycemia ≥ 300 mg/dl were used. Heart rate variability (HRV) and arterial pressure variability (APV) in time and frequency domains, symbolic analysis of heart rate (HR) and baroreflex sensitivity were evaluated. HR and arterial pressure (AP) were similar between the groups; however, HRV (total variance of RR interval: NOD=21.07 ± 3.75 vs. C = 42.02 ± 6.54 ms(2)) and the vagal modulation index RMSSD were lower in NOD group (4.01 ± 0.32 vs. 8.28 ± 0.97 ms). Moreover, the absolute and normalized low-frequency (LF) components were also enhanced in NOD (normalized = 61.0 ± 4.0%) as compared to control mice (normalized = 20.0 ± 4.0%). Both the absolute and normalized high-frequency (HF) components were lower in NOD (normalized = 39.0 ± 4.0%) when compared to the control group (normalized = 80.0 ± 4.0). In the symbolic analysis the 0V pattern, an indication of sympathetic activity, was higher in NOD and 2 LV pattern, an indication of parasympathetic activity, was lower in the NOD than in the control group. Both bradycardic and tachycardic responses were decreased in NOD (3.01 ± 0.72 vs. 4.54 ± 0.36 bpm/mmHg and 2.49 ± 0.31 vs. C = 3.43 ± 0.33 bpm/mmHg) when compared to the control group. Correlation analysis showed negative correlations between vagal indexes (RMSSD, %HF and 2LV) and glycemic levels. In conclusion, NOD mice develop severe diabetes correlated with autonomic dysfunction.