Effect of High-Intensity Interval Training on Cardiac Apoptosis Markers in Methamphetamine-Dependent Rats.

Chronic methamphetamine use increases apoptosis, leading to heart failure and sudden cardiac death. Previous studies have shown the importance of high-intensity interval training (HIIT) in reducing indices of cardiac tissue apoptosis in different patients, but in the field of sports science, the molecular mechanisms of apoptosis in methamphetamine-dependent rats are still unclear. The present article aimed to investigate the changes in cardiac apoptosis markers in methamphetamine-dependent rats in response to HIIT. Left ventricular tissue was used to evaluate caspase-3, melusin, FAK, and IQGAP1 gene expression. Rats were divided into four groups: sham, methamphetamine (METH), METH-control, and METH-HIIT. METH was injected for 21 days and then the METH-HIIT group performed HIIT for 8 weeks at 5 sessions per week. The METH groups showed increased caspase-3 gene expression and decreased melusin, FAK, and IQGAP1 when compared to the sham group. METH-HIIT showed decreased caspase-3 and increased melusin and FAK gene expression compared with the METH and METH-control groups. The IQGAP1 gene was higher in METH-HIIT when compared with METH, while no difference was observed between METH-HIIT and METH-control. Twenty-one days of METH exposure increased apoptosis markers in rat cardiac tissue; however, HIIT might have a protective effect, as shown by the apoptosis markers.

A single session of low-volume high-intensity interval and moderate-intensity continuous exercise elicits a transient reduction in ghrelin levels, but not in post-exercise energy intake in obese men

ABSTRACT Objective: This study investigated the acute effects of high-intensity interval (HIIE) and moderate-intensity continuous (MICE) exercise on ghrelin levels in obese men. Subjects and methods: A total of 10 obese men (age 27.6 ± 1.8 years, body mass index 35.4 ± 4.5 kg/m², body fat 39.9 ± 2.1%) performed two exercise sessions in a randomized order: HIIE (10 × 1 min intervals at 90% of the maximal heart rate [HRmax] interspersed by 1 min of active recovery) and MICE (20 min at 70% of the HRmax). Ghrelin levels were assessed pre-, post- and 1h post-exercise, and energy intake was assessed 1h post-exercise through an ad libitum meal. Results: HIIE and MICE showed a trend to decrease ghrelin levels immediately post-exercise (-14.1 ± 21.6% and −9.6 ± 23.8%, respectively, p = 0.07) and decreased 1h post-exercise (-12.7 ± 31.8% and −13.8 ± 21.7%, respectively, p < 0.05). No changes were observed for post-exercise energy intake (p > 0.05). There was a positive correlation between the change in ghrelin levels and post-exercise energy intake only for HIIE (r = 0.63, p = 0.05). Conclusion: In summary, a single session of HIIE and MICE elicits a reduction on ghrelin levels without changing post-exercise energy intake in obese men.

A single session of low-volume high-intensity interval and moderate-intensity continuous exercise elicits a transient reduction in ghrelin levels, but not in post-exercise energy intake in obese men.

OBJECTIVE: This study investigated the acute effects of high-intensity interval (HIIE) and moderate-intensity continuous (MICE) exercise on ghrelin levels in obese men. METHODS: A total of 10 obese men (age 27.6 ± 1.8 years, body mass index 35.4 ± 4.5 kg/m2, body fat 39.9 ± 2.1%) performed two exercise sessions in a randomized order: HIIE (10 × 1 min intervals at 90% of the maximal heart rate [HRmax] interspersed by 1 min of active recovery) and MICE (20 min at 70% of the HRmax). Ghrelin levels were assessed pre-, post- and 1h post-exercise, and energy intake was assessed 1h post-exercise through an ad libitum meal. RESULTS: HIIE and MICE showed a trend to decrease ghrelin levels immediately post-exercise (-14.1 ± 21.6% and -9.6 ± 23.8%, respectively, p = 0.07) and decreased 1h post-exercise (-12.7 ± 31.8% and -13.8 ± 21.7%, respectively, p < 0.05). No changes were observed for post-exercise energy intake (p > 0.05). There was a positive correlation between the change in ghrelin levels and post-exercise energy intake only for HIIE (r = 0.63, p = 0.05). CONCLUSION: In summary, a single session of HIIE and MICE elicits a reduction on ghrelin levels without changing post-exercise energy intake in obese men.

"NO LOAD" Resistance Training Promotes High Levels of Knee Extensor Muscles Activation-A Pilot Study.

The present article aims to compare electromyographic (EMG) activity of the knee extensors during traditional resistance training (TRT) and no load resistance training with or without visual feedback (NL-VF and NL-NF). Sixteen healthy men (age: 25.2 ± 3.6) volunteered to participate in the study. Participants visited the laboratory on three occasions involving: (1) a 10 repetition maximum test (10 RM test), (2) familiarization and (3) performance of knee extensions using TRT, NL-VF and NL-NF in a random order, with 10 min of rest between them. TRT involved the performance of a set to momentary muscle failure using the 10 RM load. NL-NF involved the performance of 10 repetitions with no external load, but with the intention to maximally contract the muscles during the whole set. NL-VF involved the same procedure as NL-NF, but a monitor was positioned in front of the participants to provide visual feedback on the EMG activity. Peak and mean EMG activity were evaluated on the vastus medialis (VM), vastus lateralis (VL) and rectus femoris (RF). Results: there were no significant differences in VM and VL peak EMG activity among different situations. There was a significant difference for peak EMG activity for RF, where TRT resulted in higher values than NL-VF and NL-NF (p < 0.05). Higher values of mean EMG activity were found for VM, VL and RF during TRT in comparison with both NL-VF and NL-NF. Conclusions: resistance training with no external load produced high levels of peak muscle activation, independent of visual feedback, but mean activation was higher during TRT. These results suggest that training with no external load might be used as a strategy for stimulating the knee extensors when there is limited access to specialized equipment. Although the clinical applications of no load resistance training are promising, it is important to perform long-term studies to test if these acute results will reflect in muscle morphological and functional changes.