Influence of pulsing electromagnetic field therapy on resting blood pressure in aging adults

This double-blind study tested the effects of pulsating electromagnetic field (PEMF) therapy sessions on the changes in peripheral cardiovascular function in a group of aging adults after 12 weeks of treatment. Each therapy session involved 15 min of exposure to low-frequency PEMF with asymmetrical waveforms emitted by the Impulser? Pro mattress. The treatment was provided 5 days per week for a total of 60 sessions. Resting blood pressure and arterial stiffness index were determined for peripheral cardiovascular function. Fifty-four older men and women (mean age 59.8 ± 3.5 yrs) completed the entire protocol involving either the PEMF or a sham treatment. The results include statistically significant reductions in systolic and pulse blood pressure, while no significant difference in diastolic pressure or the index of arterial stiffness was observed. These findings suggest that the PEMF treatment might be linked to improvements in peripheral resistance or circulation.     

An Examination of the Relationship Between Resting Heart Rate Variability and Heart Rate Reactivity to a Mental Arithmetic Stressor

Resting heart rate variability can be an index of sympathetic or parasympathetic dominance, according to the frequency of the variability studied. Sympathetic dominance of this system has been linked to increased risk of cardiovascular disease (CVD). Similarly, rapid and dramatic increases in heart rate reactivity to a stressor task have also been suggested as indicating increased risk of CVD via atherogenesis. Although both of these variables have been related to the development of cardiovascular disease, and both may be related to increased sympathetic activity or parasympathetic withdrawal, most research studies have tended to focus on either variable independently of the other. In order to investigate whether these two indices of stressor reactivity were related in relatively young and healthy subjects, resting heart rate variability data were collected from 80 volunteers for 20 minutes. In addition, heart rate reactivity data were collected during a 2-minute mental arithmetic stressor, which has been previously shown to induce significant increases in heart rate. After classifying subjects according to whether their heart rate variability data were above or below the mean for their gender, heart rate reactivity data were examined via MANOVA to detect significant differences between subject groups. Females showed significant effects, and males showed nonsignificant trends, but these two sets of data were in different directions, suggesting that gender may be a confounding factor in the relationship between heart rate reactivity and heart rate variability.     

A theoretical study of bone remodelling under PEMF at cellular level

Pulsed electromagnetic field (PEMF) devices have been used clinically to slow down osteoporosis and accelerate the healing of bone fractures for many years. However, the underlying mechanism by which bone remodelling under PEMF is regulated remains poorly understood. In this paper, a mathematical model of bone cell population of bone remodelling under PEMF at cellular level is developed to address this issue for the first time. On the basis of this model and control theory, parametric study of control mechanisms is carried out and a number of possible control mechanisms are identified. These findings will help further the understanding of bone remodelling under PEMF and advance therapies and pharmacological developments in clinical trials.     

AUTONOMIC CONTROL OF HEART RATE AFTER EXERCISE IN TRAINED WRESTLERS

The objective of this study was to establish differences in vagal reactivation, through heart rate recovery and heart rate variability post exercise, in Brazilian jiu-jitsu wrestlers (BJJW). A total of 18 male athletes were evaluated, ten highly trained (HT) and eight moderately trained (MT), who performed a maximum incremental test. At the end of the exercise, the R-R intervals were recorded during the first minute of recovery. We calculated heart rate recovery (HRR_60s), and performed linear and non-linear (standard deviation of instantaneous beat-to-beat R-R interval variability – SD1) analysis of heart rate variability (HRV), using the tachogram of the first minute of recovery divided into four segments of 15 s each (0-15 s, 15-30 s, 30-45 s, 45-60 s). Between HT and MT individuals, there were statistically significant differences in HRR_60s (p <0.05) and in the non linear analysis of HRV from SD1_30-45s (p <0.05) and SD1_45-60s (p <0.05). The results of this research suggest that heart rate kinetics during the first minute after exercise are related to training level and can be used as an index for autonomic cardiovascular control in BJJW.     

Transfer of Heart Rate Feedback Training to Reduce Heart Rate Response to Laboratory Tasks

To examine whether transfer of heart rate (HR) feedback training to tasks not used during training could be improved by using multiple tasks during training, a modified multiple baseline across tasks, single subject design study was conducted using six high HR-reactive young adults. Participants received HR feedback training during the presentation of a videogame, and transfer of training was assessed to a mental arithmetic challenge and handgrip task. Transfer of training was next assessed following training with the mental arithmetic challenge and handgrip task. HR responses to each training task with no HR feedback were assessed during a pre-treatment session, an immediate post-training period following training on each task, a short delay (1–2 days) post-training session, and a long delay (1–2 weeks) post-training session. HR response to a novel speech task was assessed at pre-treatment and during short delay and long delay post-training sessions. Results revealed that participants reduced HR during training and generally maintained this reduction in HR during the immediate post-training assessment when HR feedback was not present. Participants were not able to reduce HR responses to tasks during short delay and long delay post-training sessions, and they were unable to transfer HR reduction skills to the speech task. Transfer of HR feedback training to new tasks was limited in nature and efforts to train across multiple stressors did not appear to improve transfer of training.     

心率减速力、连续心率减速力及心率加速力与慢性心衰患者预后的相关性

摘要 目的：探讨心率减速力（deceleration capacity of heart rate, DC）、连续心率减速力（Heart Rate deceleration runs, DRs）及心率加速力（acceleration capacity of heart rate, AC）与慢性心衰患者（CHF）预后的相关性。方法：将2021年10月至2022年10月我院心内科收治的120例CHF患者纳入观察组,根据心功能分级标准分组：Ⅱ级组、Ⅲ级组、Ⅳ级组各40、50、30例,另纳入69例同期门诊体检健康志愿者为对照组,对比两组一般资料,分析DC、DRs、AC表达情况,并对观察组患者进行为期一年的随访,记录心血管事件发生情况,探讨DC、DRs、AC在心血管事件中的评估价值。结果：观察组DC、DR2、DR4、DR8、LVEF水平均显著低于对照组,LVEDD、AC高于对照组（P＜0.05）;Ⅳ级组DC、DR2、DR4、DR8、LVEF水平均显著低于Ⅲ级组、Ⅱ级组,LVEDD、AC高于Ⅲ级组、Ⅱ级组（P＜0.05）;Ⅲ级组DC、DR2、DR4、DR8、LVEF水平均显著低于Ⅱ级组,LVEDD、AC高于Ⅱ级组（P＜0.05）;事件组DC、DR2、DR4、DR8、LVEF水平均显著低于非事件组,LVEDD、AC高于非事件组（P＜0.05）;高危组恶性心律失常、心力衰竭再次住院、心源性休克、心源性死亡发生率显著高于中危组及低危组（P＜0.05）,中危组以上事件发生率亦显著高于低危组（P＜0.05）。结论：DC、DRs、AC在CHF患者心功能分级及预后评估中具有指导意义,临床可通过监测CHF患者以上指标变化情况,为治疗及预防心血管事件发生提供客观依据。     

Electric fields induced in rat and human models by 60-Hz magnetic fields: comparison of calculated and measured values.

The calculated distribution of electric fields induced in homogeneous human and rat models by a 60-Hz magnetic field is compared with values measured in instrumented mannequins. The calculated values agree well with measured values.