Exercise training early after acute ST-elevation myocardial infarction and its effect on ventricular remodeling

Funding Acknowledgements Type of funding sources: None. Background Deterioration of left ventricular function after acute myocardial infarction is common, particular in ST-elevation myocardial infarction (STEMI). This often leads to heart failure with reduced ejection fraction (HFrEF). Exercise training has shown to be beneficial in stable chronic heart failure patients. However, effects of exercise training have been rarely investigated during very early phases of STEMI. Purpose The Exercise in Acute Myocardial Infarction (Ex-AMI) pilot study wanted to investigate whether exercise training has beneficial effects on ventricular remodeling under the following conditions: a) started early after myocardial infarction b) exclusively after STEMI c) performed with higher intensity. The hypothesis of this study was that exercise training early after acute myocardial infarction performed for 24 weeks is superior to usual care, regarding the improvement of echocardiographic parameters. It was also assumed that higher-intensity interval training is more effective than moderate continuous training. Methods Therefore, we randomized 19 patients with STEMI (58.0 ± 7.1 years, 5% female) and left ventricular ejection fraction (LVEF) <55% to: 1. Moderate continuous training (MCT; 50-60% VO2peak; n = 6) 2. Higher intensity interval training (HIIT; MCT interspersed by intervals of 80-85% VO2peak; n = 6) 3. Usual care (UC; n = 7) Exercise groups (EG: MCT and HIIT) started seven days after STEMI (run-in period for two weeks, followed by a tailored supervised exercise program for 22 weeks). Three-dimensional echocardiography and cardiopulmonary exercise testing were performed at the beginning and at the end of the training period. Patients were also continuously monitored for adverse events. Results At baseline, LVEF (46.3 ± 6,5%) as well as exercise capacity (VO2peak: 17.8 ± 4.4·kg-1·min-1) were impaired. In both exercise groups (EG: MCT and HIIT) LVEF improved significantly more than in the control group (mean change +7.3 ± 3.5% in EG vs. 2.3 ± 2.3% in UC; p = 0.007). Furthermore HIIT was not superior to MCT (mean change 7.6 ± 3.6% in HIIT vs. 6.7 ± 4.1% in MCT; p = 0.78) in terms of LVEF. There were no training associated adverse events. Conclusion Exercise training early after acute STEMI seems to have anti-remodeling effects. There is a need for more randomized controlled trials to confirm these findings, in order to find the optimal timing and dose of exercise after STEMI. Abstract Figure. Changes in LVEF (in %) after 24 weeks

The effects of aerobic exercise intensity on memory in older adults

Aerobic exercise may enhance memory in older adults. However, the optimal intensity and underlying mechanism are unclear. This community-based study examined the effect of aerobic exercise intensity on memory and general cognitive abilities. Brain-derived neurotrophic factor (BDNF) was examined as a potential mechanism. Sixty-four sedentary older adults participated in 1 of 3 groups: (i) high-intensity interval training (HIIT); (ii) moderate continuous training (MCT); or (iii) stretching control (CON). Prior to and following the intervention, high-interference memory was assessed using a Mnemonic Similarity task and executive functions were assessed using Go Nogo and Flanker tasks. HIIT led to the greatest memory performance compared with MCT and CON (F[2,55] = 6.04, p = 0.004) and greater improvements in memory correlated with greater increases in fitness (rs (46) = 0.27, p = 0.03). Exercise intensity seemed to matter less for executive functioning, as positive trends were observed for both HIIT and MCT. No significant differences in BDNF were found between groups. Overall, these results suggest that aerobic exercise may enhance memory in older adults, with the potential for higher intensity exercise to yield the greatest benefit. While our findings suggest that BDNF does not regulate these adaptations, the mechanisms remain to be determined. Novelty High-intensity interval training results in the greatest memory performance in inactive older adults compared with moderate continuous training or stretching. Improvement in fitness correlates with improvement in memory performance.

High-intensity interval training is effective and superior to moderate continuous training in patients with heart failure with preserved ejection fraction: A randomized clinical trial

Background Heart failure with preserved ejection fraction (HFpEF) is a prevalent syndrome, with exercise intolerance being one of its hallmarks, contributing to worse quality of life and mortality. High-intensity interval training is an emerging training option, but its efficacy in HFpEF patients is still unknown. Design Single-blinded randomized clinical trial. Methods Single-blinded randomized clinical trial with exercise training 3 days per week for 12 weeks. HFpEF patients were randomly assigned to high-intensity interval training or moderate continuous training. At baseline and after 12 week follow-up, patients underwent clinical assessment, echocardiography and cardiopulmonary exercise testing (CPET). Results Mean age was 60 ± 9 years and 63% were women. Both groups ( N = 19) showed improved peak oxygen consumption (VO2), but high-intensity interval training patients ( n = 10) had a significantly higher increase, of 22%, compared with 11% in the moderate continuous training ( n = 9) individuals (3.5 (3.1 to 4.0) vs. 1.9 (1.2 to 2.5) mL·kg−1·min−1, p < 0.001). Ventilatory efficiency and other CPET measures, as well as quality of life score, increased equally in the two groups. Left ventricular diastolic function also improved with training, reflected by a significant reduction in E/e′ ratio by echocardiography (−2.6 (−4.3 to −1.0) vs. −2.2 (−3.6 to −0.9) for high-intensity interval training and moderate continuous training, respectively; p < 0.01). There were no exercise-related adverse events. Conclusions This randomized clinical trial provided evidence that high-intensity interval training is a potential exercise modality for HFpEF patients, being more effective than moderate continuous training in improving peak VO2. However, the two strategies were equally effective in improving ventilatory efficiency and other CPET parameters, quality of life score and diastolic function after 3 months of training.

Exercise Intensity Alter Insulin Receptor Gene Expression in Diabetic Type - 2 Rat Model

AIM: To analyse the differential expression of the insulin receptor (IR) gene between moderate continuous and severe continuous training in the T2DM rat model. METHODS: This was an experimental study. Healthy male Wistar was used in this study, which divided into sedentary, moderate continuous training, and severe continuous training. Treated groups were assigned to run on the treadmill three times a week for eight weeks consequently. RESULTS: The result shown that expression of mRNA IR gene in treated groups decline compared to control. There was a difference mRNA IR gene expression after eight weeks of exercise between MCT and control, SCT and control so are MCT and SCT. IR expression on skeletal muscle in treated groups was different compared with control. The distribution of IR on skeletal muscles in treatment groups was significantly increased compared control, but there was no significant difference distribution between MCT and SCT. HOMA-IR post-test in SCT was lower than MCT but FBG post-test lower in MCT than SCT. CONCLUSION: The intensity of exercise makes a difference in IR gene expression between moderate continuous training and severe continuous training after eight weeks of assigned exercise in T2DM rat models.