Effect of resistance exercise on cardiac perturbations and systolic performance: A cross-over randomized trial comparing volumes and techniques.

This study investigated the magnitude and time-course of resistance exercise (RE) technique induced transient cardiac perturbations. Twenty-four participants were assigned to one of four arms: sets to failure or non-failure with 8-10 repetition maximum (RM), and sets to failure or non-failure with 15RM. Echocardiographic and blood pressure (BP) data were recorded at baseline and 30 min, 6 h and 24 h post-exercise. In all groups end-systolic circumferential wall stress (cESS), and ratio of transmitral inflow velocities (E/A) were significantly decreased while posterior wall thickness (PWT), global circumferential strain (GCS), GCS strain rate (GCSR), global longitudinal strain rate (GLSR), and stroke volume (SV) were significantly increased for up to 6 h of follow-up. In the 15RM groups, left ventricular (LV) mass and interventricular septal thickness (IVST) were significantly increased, and left atrial (LA) area was significantly decreased (p < 0.05) compared to the 8-10 RM groups. In the 15RM groups, RE decreased global longitudinal strain (GLS) and increased ejection fraction (EF) (p<0.01). After RE, transient cardiac perturbations, the reduction in LA compliance, and the improvement in LV myofibril geometry were volume dependent and influenced more by sets to failure technique. RE increased GCS and reduced the afterload, thus helping to preserve SV and EF.

Treadmill Exercise Ameliorates Spatial Learning and Memory Deficits Through Improving the Clearance of Peripheral and Central Amyloid-Beta Levels.

Aggregated amyloid beta (Aß) peptides are believed to play a decisive role in the pathology of Alzheimer's disease (AD). Previous evidence suggested that exercise contributes to the improvement of cognitive decline and slows down pathogenesis of AD; however, the exact mechanisms for this have not been fully understood. Here, we evaluated the effect of a 4-week moderate treadmill exercise on spatial memory via central and peripheral Aß clearance mechanisms following developed AD-like neuropathology induced by intra-hippocampal Aß1-42 injection in male Wistar rats. We found Aß1-42-treated animals showed spatial learning and memory impairment which was accompanied by increased levels of amyloid plaque load and soluble Aß1-42 (sAß1-42), decreased mRNA and protein expression of neprilysin (NEP), insulin degrading enzyme (IDE) and low-density lipoprotein receptor-related protein-1 (LRP-1) in the hippocampus. Aß1-42-treated animals also exhibited a higher level of sAß1-42 and a lower level of soluble LRP-1 (sLRP-1) in plasma, as well as a decreased level of LRP-1 mRNA and protein content in the liver. However, exercise training improved the spatial learning and memory deficits, reduced both plaque load and sAß1-42 levels, and up-regulated expression of NEP, IDE, and LRP-1 in the hippocampus of Aß1-42-treated animals. Aß1-42-treated animals subjected to treadmill exercise also revealed decreased levels of sAß1-42 and increased levels of sLRP-1 in plasma, as well as increased levels of LRP-1 mRNA and protein in the liver. In conclusion, our findings suggest that exercise-induced improvement in both of central and peripheral Aß clearance are likely involved in ameliorating spatial learning and memory deficits in an animal model of AD. Future studies need to determine their relative contribution.