Protective effect of low-intensity treadmill exercise against acetylcholine-calcium chloride-induced atrial fibrillation in mice.

Atrial fibrillation (AF) is the most common supraventricular arrhythmia, and it corresponds highly with exercise intensity. Here, we induced AF in mice using acetylcholine (ACh)-CaCl2 for 7 days and aimed to determine the appropriate exercise intensity (no, low, moderate, high) to protect against AF by running the mice at different intensities for 4 weeks before the AF induction by ACh-CaCl2. We examined the AF-induced atrial remodeling using electrocardiogram, patch-clamp, and immunohistochemistry. After the AF induction, heart rate, % increase of heart rate, and heart weight/body weight ratio were significantly higher in all the four AF groups than in the normal control; highest in the high-ex AF and lowest in the low-ex (lower than the no-ex AF), which indicates that low-ex treated the AF. Consistent with these changes, G protein-gated inwardly rectifying K+ currents, which were induced by ACh, increased in an exercise intensity-dependent manner and were lower in the low-ex AF than the no-ex AF. The peak level of Ca2+ current (at 0 mV) increased also in an exercise intensity-dependent manner and the inactivation time constants were shorter in all AF groups except for the low-ex AF group, in which the time constant was similar to that of the control. Finally, action potential duration was shorter in all the four AF groups than in the normal control; shortest in the high-ex AF and longest in the low-ex AF. Taken together, we conclude that low-intensity exercise protects the heart from AF, whereas high-intensity exercise might exacerbate AF.

Effect of Treadmill Exercise and Probiotic Ingestion on Motor Coordination and Brain Activity in Adolescent Mice.

High-intensity exercise can lead to chronic fatigue, which reduces athletic performance. On the contrary, probiotic supplements have many health benefits, including improvement of gastrointestinal health and immunoregulation. However, the effects of probiotics combined with exercise interventions on motor functions and brain activity have not been fully explored. Therefore, this study aimed to identify the effects of probiotic supplements and aerobic exercise on motor function, immune response, and exercise intensity and probiotic ingestion. After four weeks of intervention, the motor functions were assessed by rotarod test, then the levels of cytokines, gamma-aminobutyric acid (GABA), and glutamate were detected. The improvement caused by the intake of probiotics in the moderate-intensity exercise group and the non-exercise group in the accelerating mode rotarod was significant (p = 0.038, p < 0.001, respectively). In constant-speed mode, the moderate-intensity exercise group with probiotic ingestion recorded longer runs than the corresponding non-exercise group (p = 0.023), and the improvement owing to probiotics was significant in all groups-non-exercise, moderate, and high-intensity (p = 0.036, p = 0.036, p = 0.012, respectively). The concentrations of inflammatory cytokines were lower, whereas GABA was higher in the probiotics-ingested group. Taken together, exercise and probiotics in adolescence could positively affect brain and motor function.

The effect of exercise intensity on brain derived neurotrophic factor and memory in adolescents.

BACKGROUND: Brain derived neurotrophic factor (BDNF) seems to serve as an important regulatory mechanism in the growth and development of neurons in many areas of the brain.Insulin-like growth factor 1 (IGF-1) is related to neurogenesis and regulation of the BDNF gene and is involved in the growth and differentiation of neurons.Cortisol is released in response to stimuli such as psychological oppression, anxiety, and fear. Stress also induces changes in BDNF. The purpose of this study was thus to examine the effects of varying intensities of aerobic exercise on resting serum BDNF, IGF-1 concentrations, cortisol, and memory of adolescents. METHODS: Forty male students with no history of physical illness from the middle school by participated in this study. Participants were randomly assigned to low, moderate, or high intensity treadmill exercise group, or a stretching (control) group. Exercise was performed 4 times per week for 12 weeks. Body composition, brain derived neurotrophic factor levels, insulin-like growth factor 1 levels, cortisol levels, and working memory were assessed. RESULTS: The high intensity exercise group showed a significant increase in brain derived neurotrophic factor at rest, concentration level of insulin-like growth factor 1, cortisol, and working memory. For resting brain derived neurotrophic factor, the high intensity exercise group showed a more significant increase compared to the low intensity aerobic and stretching groups. The change in the working memory significantly increased for the high intensity exercise group compared to the low intensity aerobic group, moderate intensity exercise group, and stretching group. CONCLUSIONS: In adolescents, whose brains are still developing, aerobic exercise of moderate to high intensity levels seems to have a positive effect on levels of serum brain derived neurotrophic factor at rest and on cognitive functioning. TRIAL REGISTRATION: EHPM-D-16-00107R2 . ICMJE. 12 July 2016.

Relationship of visfatin level to pancreatic endocrine hormone level, HOMA-IR index, and HOMA ß-cell index in overweight women who performed hydraulic resistance exercise.

[Purpose] This study aimed to examine the correlation of visfatin level to pancreatic endocrine hormone level, homeostasis model assessment of insulin resistance (HOMA-IR) index, and HOMA ß-cell index in hydraulic resistance exercise. Furthermore, it investigated the relationship between visfatin level and other variables affected by exercise in overweight women. [Subjects and Methods] The exercise group trained for 12 weeks, 70 minutes/day, 5 days/week. Visfatin level, pancreatic endocrine hormone level, HOMA-IR index, and HOMA ß-cell index were measured before and after the intervention. Based on the blood insulin and glucose concentrations, HOMA-IR index, the indicator of insulin resistance, and HOMA ß-cell index, the indicator of insulin secretion level, were assessed. [Results] Interaction effects on visfatin level, insulin level, HOMA-IR index, and HOMA ß-cell index were observed. Interaction effects on glucagon and glucose levels were not observed between the intervention groups. The correlations of visfatin level to insulin, glucagon, and glucose levels, and HOMA-IR and HOMA ß-cell indexes were not significant for any of the subjects. [Conclusion] Therefore, the 12-week resistance exercise affected body composition, visfatin level, insulin level, HOMA-IR index, and HOMA ß-cell index. Finally, visfatin was not related to insulin, glucagon, and glucose levels, and HOMA-IR and HOMA ß-cell indexes.

Expression of brain-derived neurotrophic factor, IGF-1 and cortisol elicited by regular aerobic exercise in adolescents.

[Purpose] This study was conducted on adolescent subjects whose brains are still developing with the purpose of identifying the effect of 8 weeks duration of aerobic exercises on the expression of BDNF, IGF-1 and cortisol, to identify effect of aerobic exercise on the expression of cortisol, BDNF and IGF-1 related to nerve cell growth. [Subjects and Methods] The subjects were 20 junior-high school students with no history of physical illness. The students were divided into an exercise group and a control group. The exercise group performed 3 treadmill exercise times per week for 8 weeks. The exercise time for the consumption of 200 kcal was calculated and the exercises were performed by each individual for 8 weeks. [Results] The exercise group showed statistically significant in increases serum BDNF and IGF-1 after 8 weeks, but cortisol showed no significant change. There were statistically significant differences between the groups in serum BDNF and IGF-1 after 8 weeks, but the difference in cortisol levels was not significant. [Conclusion] We found that long-term regular aerobic exercises has a positive effect on the enhancement of serum BDNF levels at rest and IGF-1 of adolescents who are still undergoing through brain developments.