Evaluating the Effects of an Enhanced Strength Training Program in Remote Cardiological Rehabilitation: A Shift from Aerobic Dominance-A Pilot Randomized Controlled Trial.

(1) Background: Cardiac rehabilitation often emphasizes aerobic capacity while overlooking the importance of muscle strength. This study evaluated the impact of an enhanced remote strength training program (RCR-ST) on cardiac rehabilitation. (2) Methods: In this randomized prospective study (RCT registration number SMC-9080-22), 50 patients starting cardiac rehabilitation were assessed for muscle strength, aerobic capacity, and self-reported outcomes at baseline and after 16 weeks. Participants were divided into two groups: the RCR-ST group received a targeted resistance training program via a mobile app and smartwatch, while the control group received standard care with general resistance training advice. (3) Results: The RCR-ST group demonstrated significant improvements in muscle endurance, notably in leg extension and chest press exercises, with increases of 92% compared to 25% and 92% compared to 13% in the control group, respectively. Functional assessments (5-STS and TUG tests) also showed marked improvements in agility, coordination, and balance. Both groups improved in cardiorespiratory fitness, similarly. The RCR-ST group reported enhanced physical health and showed increased engagement, as evidenced by more frequent use of the mobile app and longer participation in the rehabilitation program (p < 0.05). (4) Conclusions: Incorporating a focused strength training regimen in remote cardiac rehabilitation significantly improves muscle endurance and patient engagement. The RCR-ST program presents a promising approach for optimizing patient outcomes by addressing a crucial gap in traditional rehabilitation protocols that primarily focus on aerobic training.

Facial electromyography during exercise using soft electrode array: A feasibility study.

The use of wearable sensors for real-time monitoring of exercise-related measures has been extensively studied in recent years (e.g., performance enhancement, optimizing athlete's training, and preventing injuries). Surface electromyography (sEMG), which measures muscle activity, is a widely researched technology in exercise monitoring. However, due to their cumbersome nature, traditional sEMG electrodes are limited. In particular, facial EMG (fEMG) studies in physical training have been limited, with some scarce evidence suggesting that fEMG may be used to monitor exercise-related measurements. Altogether, sEMG recordings from facial muscles in the context of exercise have been examined relatively inadequately. In this feasibility study, we assessed the ability of a new wearable sEMG technology to measure facial muscle activity during exercise. Six young, healthy, and recreationally active participants (5 females), performed an incremental cycling exercise test until exhaustion, while facial sEMG and vastus lateralis (VL) EMG were measured. Facial sEMG signals from both natural expressions and voluntary smiles were successfully recorded. Stable recordings and high-resolution facial muscle activity mapping were achieved during different exercise intensities until exhaustion. Strong correlations were found between VL and multiple facial muscles' activity during voluntary smiles during exercise, with statistically significant coefficients ranging from 0.80 to 0.95 (p<0.05). This study demonstrates the feasibility of monitoring facial muscle activity during exercise, with potential implications for sports medicine and exercise physiology, particularly in monitoring exercise intensity and fatigue.

Home-Based Cardiac Rehabilitation Among Patients Unwilling to Participate in Hospital-Based Programs.

PURPOSE: Asynchronous home-based cardiac rehabilitation (HBCR) is a viable alternative to center-based cardiac rehabilitation (CBCR). However, to achieve significant functional improvement, a high level of adherence and activity must be achieved. The effectiveness of HBCR among patients who actively avoid CBCR has not been effectively investigated. This study aimed to investigate the effectiveness of the HBCR program among patients unwilling to participate in CBCR. METHODS: A randomized prospective study enrolled 45 participants to a 6-mo HBCR program and the remaining 24 were allocated to regular care. Both groups were digitally monitored for physical activity (PA) and self-reported outcomes. Change in peak oxygen uptake (VO 2peak ), the primary study outcome, was measured by the cardiopulmonary exercise test, immediately before program start and 4 mo thereafter. RESULTS: The study included 69 patients, 81% men, aged 55.9 ±12 yr, enrolled in a 6-mo HBCR program to follow a myocardial infarction (25.4%) or coronary interventions (41.3%), heart failure hospitalization (29%), or heart transplantation (10%). Weekly aerobic exercise totaled a median of 193.2 (110.2-251.5) min (129% of set exercise goal), of which 112 (70-150) min was in the heart rate zone recommended by the exercise physiologist.After 4 mo, VO 2peak improved by 10.2% in the intervention group versus -2.7% in the control group (+2.46 ± 2.67 vs -0.72 ± 3.02 mL/kg/min; P < .001). CONCLUSION: The monthly PA of patients in the HBCR versus conventional CBCR group were well within guideline recommendations, showing a significant improvement in cardiorespiratory fitness. Risk level, age, and lack of motivation at the beginning of the program did not prevent achieving goals and maintaining adherence.

Thermographic Changes following Short-Term High-Intensity Anaerobic Exercise.

Current studies report thermographic changes following aerobic or resistance exercise but not short, vigorous anaerobic exercise. Therefore, we investigated body surface temperature changes using thermal imaging following a short session of anaerobic exercise. We studied three different regions of interest (ROIs): the legs, chest, and forehead. Thermal imaging for each participant was performed before and immediately after completing a Wingate anaerobic test and every minute during a 15 min recovery period. Immediately after the test, the maximum temperature was significantly higher in all ROIs (legs, p = 0.0323; chest, p = 0.0455; forehead, p = 0.0444) compared to pre-test values. During the recovery period, both legs showed a significant and continuous temperature increase (right leg, p = 0.0272; left leg, p = 0.0382), whereas a non-significant drop was noted in the chest and forehead temperatures. Additionally, participants with a lower anaerobic capacity exhibited a higher delta increase in surface leg temperature than participants with higher anaerobic capacities, with a minimal change in surface leg temperature. This is the first study to demonstrate body surface temperature changes following the Wingate anaerobic test. This temperature increase is attributed to the high anaerobic mechanical power outputs achieved by the leg muscles and the time taken for temperature reduction post-exercise.

Israel's first national remote cardiac rehabilitation program: A retrospective analysis.

Aims: Cardiac rehabilitation is an essential component of secondary prevention consistently unexploited by most eligible patients. Accordingly, the remote cardiac rehabilitation program (RCRP) was developed to create optimal conditions for remote instruction and supervision for patients to enable successful completion of the program. Methods: This study comprised 306 patients with established coronary heart disease who underwent a 6-month RCRP. RCRP involves regular exercise, monitored by a smartwatch that relays data to the operations center and a mobile application on the patient's smartphone. A stress test was performed immediately before the RCRP and repeated after 3 months. The aims were to determine the effectiveness of the RCRP in improving aerobic capacity, and correlating the program goals and first-month activity, with attaining program goals during the last month. Results: Participants were mostly male (81.5%), aged 58 ± 11, enrolled in the main after a myocardial infarction or coronary interventions. Patients exercised aerobically for 183 min each week, 101 min (55% of total exercise) at the target heart rate. There was a significant improvement in exercise capacity, assessed by stress tests, metabolic equivalents which increased from 9.5 ± 3 to 11.4 ± 7(p < 0.001). Independent predictors of RCRP goals were older age and more minutes of aerobic exercise during the first program month (p < 0.05). Conclusion: Participants succeeded in performing guideline recommendations, resulting in a significant improvement in exercise capacity. Older age and increased volume of first month of exercise were significant factors associated with a greater likelihood to attain program goals.

A computational predictor of the anaerobic mechanical power outputs from a clinical exercise stress test.

We previously were able to predict the anaerobic mechanical power outputs using features taken from a maximal incremental cardiopulmonary exercise stress test (CPET). Since a standard aerobic exercise stress test (with electrocardiogram and blood pressure measurements) has no gas exchange measurement and is more popular than CPET, our goal, in the current paper, was to investigate whether features taken from a clinical exercise stress test (GXT), either submaximal or maximal, can predict the anaerobic mechanical power outputs to the same level as we found with CPET variables. We have used data taken from young healthy subjects undergoing CPET aerobic test and the Wingate anaerobic test, and developed a computational predictive algorithm, based on greedy heuristic multiple linear regression, which enabled the prediction of the anaerobic mechanical power outputs from a corresponding GXT measures (exercise test time, treadmill speed and slope). We found that for submaximal GXT of 85% age predicted HRmax, a combination of 3 and 4 variables produced a correlation of r = 0.93 and r = 0.92 with % error equal to 15 ± 3 and 16 ± 3 on the validation set between real and predicted values of the peak and mean anaerobic mechanical power outputs (p < 0.001), respectively. For maximal GXT (100% of age predicted HRmax), a combination of 4 and 2 variables produced a correlation of r = 0.92 and r = 0.94 with % error equal to 12 ± 2 and 14 ± 3 on the validation set between real and predicted values of the peak and mean anaerobic mechanical power outputs (p < 0.001), respectively. The newly developed model allows to accurately predict the anaerobic mechanical power outputs from a standard, submaximal and maximal GXT. Nevertheless, in the current study the subjects were healthy, normal individuals and therefore the assessment of additional subjects is desirable for the development of a test applicable to other populations.

Unilateral Increase of Gustatory Thresholds in Acute Otitis Media: A Pilot Study.

BACKGROUND: To evaluate chorda tympani nerve function as measured by unilateral increases of gustatory thresholds in the presence of ipsilateral acute otitis media. METHODS: Prospective clinical study comparing electrogustometric measurements was conducted to evaluate the taste thresholds of each side of the tongue in a patient during an acute episode of unilateral acute otitis media. Included were patients aged 12-40 who presented to the emergency department and outpatient ear, nose, and throat clinic of a university-affiliate tertiary medical center with unilateral acute otitis media between January 2019 and January 2020 and consented to the study. RESULTS: Eleven patients were initially recruited into the study, and 10 patients aged (mean ± standard deviation) 26.1 ± 11.2 years comprised the final study group. Taste thresholds were significantly elevated on the side ipsilateral to the ear affected by acute otitis media (P < .05). CONCLUSION: Chorda tympani nerve conductance is impaired during the acute stage of acute otitis media. This may have implications in the understanding of peripheral neural properties during acute middle ear inflammatory conditions and on the diagnosis of acute otitis media.

A higher frequency of physical activity is associated with reduced rates of SARS-CoV-2 infection.

BACKGROUND: Physical activity (PA) is associated with health benefits. Previous studies have shown that regular PA decreases the incidence of viral respiratory tract infections, but data on severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection are unavailable. OBJECTIVES: The objective of this study is to examine the association between PA frequency and SARS-CoV-2 infection. METHODS: A population-based cross-sectional study was conducted on data from 1 February 2020 to 31 December 2020, using the registry of Leumit Health Services (LHS), a national health maintenance organisation in Israel. All LHS patients aged 18 to 80 years who underwent at least one RT-PCR test for SARS-CoV-2 during the study period were included. We examined the association between PA frequency (hours per week) and being tested positive for SARS-CoV-2. RESULTS: Of 113,075 subjects tested for SARS-CoV-2 by RT-PCR (mean age 41.6 years, 54.4% female), 17,465 (15%) were positive. In the SARS-CoV-2-negative group, significantly more subjects were engaged with PA than in the SARS-CoV-2-positive group [crude odds ratio (OR) for any PA 0.75 (95% confidence interval (CI) 0.72-0.77)]. After adjusting for possible confounders, PA frequency had a significant negative association with the likelihood of being SARS-CoV-2 positive (adjusted OR 0.67, 95% CI 0.64-0.68). Moreover, as the frequency of PA increased, the ORs of being SARS-CoV-2-positive decreased (occasional PA: OR 0.71, 95% CI 0.67-0.74; PA 1-3 times/week: OR 0.62, 95% CI 0.58-0.65 and PA > 3 times/week: OR 0.54, 95% CI 0.49 - 0.59). CONCLUSION: Our large population-based study in patients undergoing SARS-CoV-2 RT-PCR testing showed that a higher frequency of PA is associated with a lower rate of positive test results.

The First National Program of Remote Cardiac Rehabilitation in Israel-Goal Achievements, Adherence, and Responsiveness in Older Adult Patients: Retrospective Analysis.

BACKGROUND: Remote cardiac rehabilitation (RCR) after myocardial infarction is an innovative Israeli national program in the field of telecardiology. RCR is included in the Israeli health coverage for all citizens. It is generally accepted that telemedicine programs better apply to younger patients because it is thought that they are more technologically literate than are older patients. It has also previously been thought that older patients have difficulty using technology-based programs and attaining program goals. OBJECTIVE: The objectives of this study were as follows: to study patterns of physical activity, goal achievement, and improvement in functional capacity among patients undergoing RCR over 65 years old compared to those of younger patients; and to identify predictors of better adherence with the RCR program. METHODS: A retrospective study of patients post-myocardial infarction were enrolled in a 6-month RCR program. The activity of the patients was monitored using a smartwatch. The data were collected and analyzed by a special telemedicine platform. RCR program goals were as follows: 150 minutes of aerobic activity per week, 120 minutes of the activity in the target heart rate recommended by the exercise physiologist, and 8000 steps per day. Models were created to evaluate variables predicting adherence with the program. RESULTS: Out of 306 patients, 80 were older adults (mean age 70 years, SD 3.4 years). At the end of the program, there was a significant improvement in the functional capacity of all patients (P=.002). Specifically, the older adult group improved from a mean 8.1 (SD 2.8) to 11.2 (SD 12.6). The metabolic equivalents of task (METs) and final MET results were similar among older and younger patients. During the entire program period, the older adult group showed better achievement of program goals compared to younger patients (P=.03). Additionally, we found that younger patient age is an independent predictor of early dropout from the program and completion of program goals (P=.045); younger patients were more likely to experience early program dropout and to complete fewer program goals. CONCLUSIONS: Older adult patients demonstrated better compliance and achievement of the goals of the remote rehabilitation program in comparison with younger patients. We found that older age is not a limitation but rather a predictor of better RCR program compliance and program goal achievement.

[RECOMMENDATIONS FOR CHANGING CARDIOVASCULAR SCREENING OF ATHLETES WHO ARE REQUIRED FOR PRE-PARTICIPATION SCREENING UNDER THE SPORTS LAW - A POSITION PAPER ON BEHALF OF THE ISRAEL HEART SOCIETY].

INTRODUCTION: For many years routine screening of athletes in Israel includes frequently performed ECGs and exercise tests that overload the system with questionable benefits. The purpose of the current document is to reevaluate the need for pre-participation testing and establish new evidence-based guidelines. It should be noted that our proposal for a change of approach relates only to subjects whose health questionnaire is normal, who do not have a family history of sudden and unexpected death at an early age, or a family history of hereditary heart disease and whose physical examination from a cardiovascular point of view is normal.

Body mass, cardiorespiratory fitness, and cardiometabolic risk over time: Findings from the Cooper Center Longitudinal Study.

Few studies have adequately assessed the simultaneous effects of changes in cardiorespiratory fitness (fitness) and body mass on cardiometabolic risk. Hence, the current study's aims were twofold: (1) To determine whether increases in body mass result in higher cardiometabolic risk after controlling for fitness changes; and (2) To assess whether increases in fitness result in lower cardiometabolic risk after controlling for weight changes. The study consisted of 3534 patients who came for preventive medicine visits ≥4 times over any 10-year period (1979-2019). The primary independent variables were body mass and fitness, and the dependent variable was metabolic syndrome (MetS) and its components. Mixed-effects regression was used to model the relationship between changes in body mass, fitness, and MetS. Results indicate that increasing body mass up to a 10-year period was significantly related to increasing risk of MetS while controlling for changes in fitness. Specifically, a 1-kg increase in body mass was associated with a 17% (OR = 1.17; 95% CI 1.15-1.19) increased odds for MetS, while adjusting for fitness changes. A 1-MET increase in fitness was related to a 23% (OR = 0.77; 95% CI 0.70-0.84) decrease in odds for MetS, while adjusting for body mass changes up to 10 years. Moreover, body mass change was significantly related to changes in all cardiometabolic components of MetS. Fitness change was significantly associated with changes in MetS components. Future interventions should focus concurrently on increasing fitness and on body mass loss (or maintenance) to improve cardiometabolic health.

A Machine Learning Approach to the Interpretation of Cardiopulmonary Exercise Tests: Development and Validation.

OBJECTIVE: At present, there is no consensus on the best strategy for interpreting the cardiopulmonary exercise test's (CPET) results. This study is aimed at assessing the potential of using computer-aided algorithms to evaluate CPET data for identifying chronic heart failure (CHF) and chronic obstructive pulmonary disease (COPD). METHODS: Data from 234 CPET files from the Pulmonary Institute, at Sheba Medical Center, and the Givat-Washington College, both in Israel, were selected for this study. The selected CPET files included patients with confirmed primary CHF (n = 73), COPD (n = 75), and healthy subjects (n = 86). Of the 234 CPETs, 150 (50 in each group) tests were used for the support vector machine (SVM) learning stage, and the remaining 84 tests were used for the model validation. The performance of the SVM interpretive module was assessed by comparing its interpretation output with the conventional clinical diagnosis using distribution analysis. RESULTS: The disease classification results show that the overall predictive power of the proposed interpretive model ranged from 96% to 100%, indicating very high predictive power. Furthermore, the sensitivity, specificity, and overall precision of the proposed interpretive module were 99%, 99%, and 99%, respectively. CONCLUSIONS: The proposed new computer-aided CPET interpretive module was found to be highly sensitive and specific in classifying patients with CHF or COPD, or healthy. Comparable modules may well be applied to additional and larger populations (pathologies and exercise limitations), thereby making this tool powerful and clinically applicable.

Assessing rectal temperature with a novel non-invasive sensor.

Athletes, soldiers, and workers who perform intense physical activities under extreme hot conditions might encounter increased physiological thermal strain. Consequently, the increase in body core temperature (Tc) might result in heat exhaustion and heatstroke. Thus, continuously following changes in Tc is of utmost importance. Recently, the Tcore sensor (Dräger, Germany), which employs a unique dual-sensor heat flux technology, became commercially available to measure Tc, in a hospital-controlled environment. This study aimed to evaluate the possibility of using the Tcore sensor to accurately monitor rectal temperature (Tre), reflecting Tc, under exercise-heat stress. Thirteen healthy young males completed the study protocol, consisting of 90 min of moderate exercise (walking on a treadmill - 5 km/h, 4% elevation) under controlled hot/dry and hot/wet climatic conditions (30 °C/60% rh, 34 °C/40% rh, and 40 °C/40% rh). Tcore sensors were placed on the forehead and the left wrist. Temperatures from both Tcore sensors were recorded continuously together with Tre using a rectal thermistor. The original algorithm used by the company to estimate Tre from the Tcore sensor was found to be inadequate under the study's conditions and new models for the forehead and the wrist measurements were developed. Nearly 150,000 measurement sets (after filtering) were used to build independent MATLAB software algorithms and test their reliability according to the cross-validation algorithm. Bland-Altman analysis was used to compare between the results obtained by the new models to Tre. The database consisted of a large Tre range (36.5-38.9 °C). The mean errors of the models were close to zero, and the mean absolute errors were 0.20 ± 0.16 °C and 0.27 ± 0.20 °C for the forehead and wrist, respectively. 95% of the measurements from the forehead model and 86% from the wrist model were within ±0.5 °C of Tre, and 78% (forehead) and 64% (wrist) were within ±0.3 °C. Root Mean Square Deviation (RMSD) values were 0.29 °C and 0.40 °C for the forehead and wrist models, respectively. The developed models show the feasibility to use the Tcore sensor for assessing Tre under exercise-heat conditions. Furthermore, the sensor was found to be adequate for use on the wrist as well, which might be more practical for use in field conditions.

A Pulsed Electromagnetic Field Therapy Device for Non-Specific Low Back Pain: A Pilot Randomized Controlled Trial.

INTRODUCTION: Low back pain (LBP) poses a significant burden of disease worldwide, and identifying safe and effective non-pharmacologic treatment options for LBP is a research priority. The aim of this study was to pilot a clinical trial of a portable pulsed electromagnetic field (PEMF) therapy device for subjects with mixed duration non-specific LBP. METHODS: This work was a randomized, double-blind, sham-controlled, parallel-group study conducted at a chiropractic school outpatient clinic. The primary end point was functional capacity measured by the Oswestry Disability Index (ODI) at baseline, 6 weeks, and 12 weeks. Analysis was conducted on the intent-to-treat population and as a trend of change in pain scores over time using the Freidman test of repeated measures. RESULTS: Forty-two participants were randomized to receive usual care plus PEMF therapy or usual care plus sham, and 25 completed the study. Significant improvements in ODI scores from baseline to week 6 were reported in the experimental group (χ2 = 14.68, p < 0.001, compared with patients in the sham group, χ2 = 4.00, p = 0.135, n.s.). This difference persisted at week-12 follow-up. Adverse events were rare and mild. CONCLUSION: It is feasible to conduct a clinical trial of a PEMF therapy device for non-specific LBP. This work shows that the device was safe and provides preliminary evidence of effectiveness in improving function in patients with non-specific LBP. TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT03053375. FUNDING: Aerotel Ltd.

Prediction of the Wingate anaerobic mechanical power outputs from a maximal incremental cardiopulmonary exercise stress test using machine-learning approach.

The Wingate Anaerobic Test (WAnT) is a short-term maximal intensity cycle ergometer test, which provides anaerobic mechanical power output variables. Despite the physiological significance of the variables extracted from the WAnT, the test is very intense, and generally applies for athletes. Our goal, in this paper, was to develop a new approach to predict the anaerobic mechanical power outputs using maximal incremental cardiopulmonary exercise stress test (CPET). We hypothesized that maximal incremental exercise stress test hold hidden information about the anaerobic components, which can be directly translated into mechanical power outputs. We therefore designed a computational model that included aerobic variables (features), and used a new computational \ predictive algorithm, which enabled the prediction of the anaerobic mechanical power outputs. We analyzed the chosen predicted features using clustering on a network. For peak power (PP) and mean power (MP) outputs, the equations included six features and four features, respectively. The combination of these features produced a prediction model of r = 0.94 and r = 0.9, respectively, on the validation set between the real and predicted PP/MP values (P< 0.001). The newly predictive model allows the accurate prediction of the anaerobic mechanical power outputs at high accuracy. The assessment of additional tests is desired for the development of a robust application for athletes, older individuals, and/or non-healthy populations.

Effect of cardiovascular and muscular endurance is not associated with stress fracture incidence in female military recruits: a 12-month follow up study.

BACKGROUND: Stress fracture (SF) is a common injury among military recruits, especially among women, during the army basic training (ABT). The purpose of this study was to evaluate the effects of health habits and physical activity before recruitment on the fitness level and the incidence of SF during the 4-month ABT. METHODS: We screened 226 female recruit volunteers (weight: 60.5±10 kg; height: 163±6 cm) from an integrated combat unit and 124 aged-matched female controls (weight: 57.0±8.3 kg, height 162±7 cm) from a non-combat unit. A self-report questionnaire on their habits pertaining to smoking, physical activity, and orthopedic injuries prior to recruitment were analyzed in relation to the incidences of SF during ABT. RESULTS: Aerobic fitness was similar between the two groups. The overall incidence of SFs was 10.2%. Physical training prior to recruitment had no significant effect on the incidence of SF during ABT (11.7% vs. 9.6% in those who trained and did not train before recruitment, respectively) (Odds ratio, OR)=1.24, p=0.236). Nearly 42% of the female recruits smoked regularly, and the incidence of SFs among smokers was 10.5% compared with 9.9% among the non-smokers (OR=1.07, p=0.188). The overall incidence of SFs 12 months after recruitment was 1.78%. The use of contraceptive medication did not affect the incidence of SF: 10.0% among prior-trained vs. 6.4% in non-prior trained (p>0.05) recruits. SFs were not correlated to these variables at the end of the ABT program and 16 months after recruitment. CONCLUSIONS: In the present female cohort, physical activity prior to recruitment had no protective effect against SF during or after ABT. The incidence of SFs during the 12-month period after ABT was negligible.

Weak electromagnetic fields alter Ca(2+) handling and protect against hypoxia-mediated damage in primary newborn rat myotube cultures.

Weak electromagnetic fields (WEF) enhance Ca(2+) entry into cells via voltage-gated Ca(2+) channels and affect various aspects of metabolism, structure, and function. However, little information is available on the effect of WEF on skeletal muscle, which depends primarily on intracellular Ca(2+) stores for function and metabolism. Here, we examine the effects of 30 min exposure of rat primary myotube cultures to WEF (1.75 µT, 16 Hz) on Ca(2+) handling and creatine kinase (CK) release. Free myoplasmic Ca(2+) concentration ([Ca(2+) i]) was measured with the ratiometric dye indo-1. WEF did not affect basal [Ca(2+)]i but decreased the twitch [Ca(2+)]i transient in a time-dependent manner, and the twitch amplitude was decreased to ∼30 % after 30 min. WEF completely abolished the increase in [Ca(2+)]i induced by potassium chloride (∼60 mM) but had no effect on the increase induced by caffeine (∼6 mM). Hypoxia (2 h exposure to 100 % argon) resulted in a marked loss of CK into the medium (400 % of normoxic value), as well as a rapid (within 20 min) and sustained increase in basal [Ca(2+)]i (∼20 % above baseline). However, during exposure to WEF, basal [Ca(2+)]i remained constant during the initial 60 min of hypoxia and, thereafter, increased to levels similar to those observed in the absence of WEF. Finally, WEF blocked about 80 % of hypoxia-mediated CK release (P < 0.05). These data demonstrate that WEF inhibits increases in [Ca(2+)]i by interfering with muscle excitation and protects against muscle damage induced by hypoxia. Thus, WEF may have therapeutic/protective effects on skeletal muscle.

Cardiac KATP channel modulation by 16Hz magnetic fields - A theoretical study.

Heart exposure to 16Hz magnetic fields (MFs) was shown to be cardio-protective for diseased hearts; still, the mechanism of this effect is unknown. We hypothesize that a possible one mechanism is an increased trans-membrane KATP channel open probability due to modulation of the degree of dissociation between K+ ions, having a resonance frequency of 16Hz, and the channel selectivity filter. The Fan-Makielski Markovian KATP channel model was adopted, and the MF bio-effect was manifested by modulating the open probability of the channel using the predictive MF bio-effect parameter based on Binhi's quantum mechanics model. The model was integrated in a ventricular single cell model and the MF effect on the calcium transients [Ca2+] was assessed. Periodic pacing (Cycle Length CL=1sec) was applied and a 16Hz or 32Hz MF was turned on at t=0 for 10min. MF exposure gradually decreased [Ca2+] due to KATP channel opening, more strongly at 16Hz. Additionally, a small negative diastolic shift was observed. These numerical results demonstrated similarity to published experimental data using similar 16Hz MF exposure. We conclude that 16Hz MF exposure increases the KATP channel open probability, lowering the cellular calcium load. Our model could be integrated in a tissue model to predict optimal MF parameters for future cardiac therapy devices.