Serum procalcitonin levels are associated with rhabdomyolysis following exertional heatstroke: an over 10-year intensive care survey

BACKGROUND:Heatstroke has become a common emergency event in hospitals.Procalcitonin(PCT)is used as a biomarker of infection in the emergency department(ED),but its role in rhabdomyolysis(RM)following exertional heatstroke(EHS)remains unclear.METHODS:A retrospective cohort study enrolled patients with EHS from the intensive care unit(ICU).We collected RM biomarkers,inflammation markers,critical disease scores at admission,24 h,48 h,and discharge,and 90-day mortality.Correlation analysis,linear regression and curve fi tting were used to identify the relationship between PCT and RM.RESULTS:A total of 162 patients were recruited and divided into RM(n=56)and non-RM(n=106)groups.PCT was positively correlated with myoglobin(Mb),acute hepatic injury,disseminated intravascular coagulation(DIC),Sequential Organ Failure Assessment(SOFA)score,and Acute Physiology and Chronic Health Evaluation II(APACHE II)score,with correlation coefficients of 0.214,0.237,0.285,0.454,and 0.368,respectively(all P<0.05).Interestingly,the results of curve fi tting revealed a nonlinear relationship between PCT and RM,and a two-piecewise linear regression model showed that PCT was related to RM with an odds ratio of 1.3 and a cut-off of<4.6 ng/mL.Survival analysis revealed that RM was associated with higher mortality compared to non-RM cases(P=0.0093).CONCLUSION:High serum PCT concentrations are associated with RM after EHS in critically ill patients.Elevated PCT concentrations should be interpreted cautiously in patients with EHS in the ED.

Clinical Study of Shentong Zhuyu Decoction Combined with Massage Therapy in the Treatment of Exertional Chronic Lumbar Muscle Strain

[Objectives]To explore the effects of Shentong Zhuyu decoction combined with massage therapy in the treatment of exertional chronic lumbar muscle strain.[Methods]Sixty-four cases of exertional chronic lumbar muscle strain were randomly divided into two groups(32 cases each group).The patients in the control group only took celecoxib capsules,and those in the treatment group additionally took Shentong Zhuyu decoction combined with massage therapy.TCM syndrome score,lumbar function,hemorrheology index and clinical effect were compared between the two groups before and after treatment.[Results]After treatment,the TCM syndrome scores of lumbar distension/dull pain,tingling-like lumbago,adverse lateral turn,body weight loss,dark purple tongue,slow or astringent pulse,and Oswestry disability index(ODI)score in the treatment group were lower than those in the control group,and the levels of plasma viscosity,red blood cell aggregation index,platelet aggregation rate(PAG)and fibrinogen(Fib)were lower than those in the control group,showing statistical significance(P<0.05).The overall clinical effect distribution of the treatment group was better than that of the control group,and the difference was statistically significant(P<0.05).[Conclusions]Shentong Zhuyu decoction combined with massage therapy can effectively relieve the symptoms of patients with lumbago and improve the lumbar mobility function and hemorrheology,with obvious therapeutic effects in the treatment of exertional chronic lumbar muscle strain.

Exertional Rhabdomyolysis Induced Acute Kidney Injury: A Case Report and Literature Review

Background: The exRML (exertional rhabdomyolysis) is a pathophysiologic condition of skeletal muscle cell damage and breakdown associated with high intensity or prolonged exercise, normal exercise under extreme circumstances, or sudden and excessive skeletal muscle contraction. It may manifest from the increase in CK (creatine kinase) or MYO (myoglobin), a protein that can cause life-threatening injury to the kidney (AKI, acute kidney injury), and may or may not be associated with myoglobinuria. Here, we presented a case of exRML with AKI, and then reviewed the related reports. Vigorous hydration, sodium bicarbonate and furosemide are key treatments. Aim: To examine an elderly patient with exRML induced AKI and the key treatment process. Case summary: A 61-year-old man left our hospital without permission after his admission and has been walking for almost 30 kms with no water and food intake, then was diagnosed exRML and exRML induced AKI with an obvious elevation of CK, MYO and decrease of eGFR (estimated glomerular filtration rate) after coming back, and was treated with vigorous hydration, loop diuresis, sodium bicarbonate, prostaglandin and Shenkang injection. After vigorous resuscitation, the patient’s renal function, CK and MYO returned normal. Conclusions: The exRML can cause serious complications such as AKI and death. Delayed diagnosis can be critical;therefore, manner of time should be taken to achieve a favorable prognosis.

A nomogram based on lymphocyte percentage for predicting hospital mortality in exertional heatstroke patients: a 13-year retrospective study

BACKGROUND: Exertional heatstroke(EHS) is a life-threatening disease without ideal prognostic markers for predicting hospital mortality.METHODS: This is a single-center retrospective study. Clinical data from EHS patients admitted to the Intensive Care Unit(ICU) of the General Hospital of Southern Theatre Command between January 1, 2008, and December 31, 2020, were recorded and analyzed. Univariate and multivariate logistic regression were used to identify the factors for mortality. The prediction model was developed with the prognostic markers, and a nomogram was established.RESULTS: The study ultimately enrolled 156 patients, and 15(9.6%) of patients died before discharge. The lymphocyte count(Lym) and percentage(Lym%) were significantly lower in nonsurvivors(P<0.05). The univariate and multivariate logistic regression analyses indicated that Lym% at the third day of admission(Lym% D3)(OR=0.609, 95%CI: 0.454–0.816) and hematocrit(HCT)(OR=0.908, 95%CI: 0.834–0.988) were independent protective factors for hospital mortality. A nomogram incorporating Lym% D3 with HCT was developed and demonstrated good discrimination and calibration ability. The comparison between the prediction model and scoring systems revealed that the prediction model had the largest area under the curve(AUC)(0.948, 95%CI: 0.900–0.977), with 100.00% sensitivity and 83.69% specificity, and a greater clinical net benefit.CONCLUSION: Severe EHS patients had a higher risk of experiencing prolonged lymphopenia. A nomogram based on Lym% D3 and HCT was developed to facilitate early identification and timely treatment of patients with potentially unfavorable prognoses.

Establishment and effectiveness evaluation of a scoring system for exertional heat stroke by retrospective analysis

Background: Heat stroke(HS) is a serious, life-threatening disease. However, there is no scoring system for HS so far. This research is to establish a scoring system that can quantitatively assess the severity of exertional heat stroke(EHS).Methods: Data were collected from a total of 170 exertional heat stroke(EHS) patients between 2005 and 2016 from 52 hospitals in China. Univariate statistical methods and comparison of the area under the receiver operating characteristic(ROC) curve(AUC) were used to screen exertional heat stroke score(EHSS) parameters, including but not limited body temperature(T), Glasgow Coma Scale(GCS) and others. By comparing the sizes of the AUCs of the APACHE II, SOFA and EHSS assessments, the effectiveness of EHSS in evaluating the prognosis of EHS patients was verified.Results: Through screening with a series of methods, as described above, the present study determined 12 parameters – body temperature(T), GCS, p H, lactate(Lac), platelet count(PLT), prothrombin time(PT), fibrinogen(Fib), troponin I(Tn I), aspartate aminotransferase(AST), total bilirubin(TBIL), creatinine(Cr) and acute gastrointestinal injury(AGI) classification – as EHSS parameters. It is a 0–47 point system designed to reflect increasing severity of heat stroke. Low(EHSS<20) and high scores(EHSS>35) showed 100% survival and 100% mortality, respectively. We found that AUCEHSS>AUCSOFA>AUCAPACHE II.Conclusions: A total of 12 parameters – T, GCS, p H, Lac, PLT, PT, Fib, Tn I, AST, TBIL, Cr and gastrointestinal AGI classification – are the EHSS parameters with the best effectiveness in evaluating the prognosis of EHS patients. As EHSS score increases, the mortality rate of EHS patients gradually increases.

Effects of music and video on perceived exertion during high-intensity exercise

Background: Dissociative attentional stimuli(e.g., music, video) are effective in decreasing ratings of perceived exertion(RPE) during low-tomoderate intensity exercise, but have inconsistent results during exercise at higher intensity. The purpose of this study was to assess attentional focus and RPE during high-intensity exercise as a function of being exposed to music, video, both(music and video), or a no-treatment control condition.Methods: During the first session, healthy men(n = 15) completed a maximal fitness test to determine the workload necessary for high-intensity exercise(operationalized as 125% ventilatory threshold) to be performed during subsequent sessions. On 4 subsequent days, they completed 20 min of high-intensity exercise in a no-treatment control condition or while listening to music, watching a video, or both. Attentional focus, RPE,heart rate, and distance covered were measured every 4 min during the exercise.Results: Music and video in combination resulted in significantly lower RPE across time(partial η~2= 0.36) and the size of the effect increased over time(partial η~2= 0.14). Additionally, music and video in combination resulted in a significantly more dissociative focus than the other conditions(partial η~2= 0.29).Conclusion: Music and video in combination may result in lower perceived exertion during high-intensity exercise when compared to music or video in isolation. Future research will be necessary to test if reductions in perceived exertion in response to dissociative attentional stimuli have implications for exercise adherence.

Exertional rhabdomyolysis and heat stroke: Beware of volatile anesthetic sedation

In view of the enormous popularity of mass sporting events such as half-marathons, the number of patients with exertional rhabdomyolysis or exercise-induced heat stroke admitted to intensive care units(ICUs) has increased over the last decade. Because these patients have been reported to be at risk for malignant hyperthermia during general anesthesia, the intensive care community should bear in mind that the same risk of life-threatening rhabdomyolysis is present when these patients are admitted to an ICU, and volatile anesthetic sedation is chosen as the sedative technique. As illustrated by the three case studies we elaborate upon, a thorough diagnostic work-up is needed to clarify the subsequent risk of strenuous exercise, and the anesthetic exposure to volatile agents in these patients and their families. Other contraindications for the use of volatile intensive care sedation consist of known malignant hyperthermia susceptibility, congenital myopathies, Duchenne muscular dystrophy, and intracranial hypertension.

The influence of core affect on cyclo-ergometer endurance performance:Effects on performance outcomes and perceived exertion

Background:Core affect is defined as the most general affective construct consciously accessible that is experienced constantly.It can be experienced as free-floating(mood)or related to prototypical emotional episodes.The aim of this study was to examine the influence of pleasant and unpleasant core affect on cyclo-ergometer endurance performance.Specifically,we considered the influence of pleasant and unpleasant core affect on performance outcomes(i.e.,time to task completion)and rate of perceived exertion(RPE;Borg Scale,category ratio-10)collected during the task.Methods:Thirty-one participants aged 20-28 years were recruited.Core affect was randomly elicited by 2 sets of pleasant and unpleasant pictures chosen from the international affective picture system.Pictures were displayed to participants during a cyclo-ergometer performance in 2 days in a counterbalanced order.RPE was collected every minute to detect volunteers’exhaustion.Results:The study sample was split into 2 groups.Group 1 comprised participants who performed better with pleasant core affect,whereas Group 2 included participants who performed better with unpleasant core affect.Mixed between-within subjects analysis of variance revealed a significant 2(group)×2(condition)×5(isotime)interaction(p=0.002,ηp^2=0.158).Post hoc comparisons showed that participants who obtained better performance with pleasant core affect(pleasant pictures;Group 1)reported lower RPE values at 75%of time to exhaustion in a pleasant core affect condition compared to an unpleasant core affect condition.On the other hand,participants who obtained better performance with unpleasant core affect(unpleasant pictures;Group 2)reported lower RPE values at 75%and 100%of time to exhaustion in an unpleasant core affect condition.Conclusion:Findings suggest differential effects of pleasant and unpleasant core affect on performance.Moreover,core affect was found to influence perceived exertion and performance according to participants’preferences for pleasant or unpleasant core affect.

Endoscopic fasciotomy for chronic exertional compartment syndrome of the forearm:Systematic review of outcomes and complications

BACKGROUND Endoscopic fasciotomy of the forearm for chronic exertional compartment syndrome(CECS)has gained popularity recently.AIM To systematically review the literature of endoscopic fasciotomy for CECS of the forearm,aiming to assess the outcomes and complications of the different endoscopic fasciotomy techniques described in the literature.METHODS On January 18,2021,PubMed and EMBASE were searched by 3 reviewers independently,and all relevant studies published up to that date were considered based on predetermined inclusion/exclusion criteria.The subject headings“endoscopic fasciotomy”and“compartment syndrome”and their related key terms were used.The Preferred Reporting Item for Systematic Reviews and Meta-Analyses statement was used to screen the articles.RESULTS A total of seven studies including 183 patients(355 forearms)were included.The mean age of the patients was 31.2 years(range:15-42 years).The postoperative follow-up duration ranged from 6 wk to 4.9 years.All patients were able to return to sport activities between postoperative weeks 1 to 8.Recurrence of the compartment syndrome occurred in three patients,giving a rate of 1.6%per patient and 0.8%per forearm.The overall complication rate was 8.7%per patient,and 4.5%per forearm.The most common reported complication was hematoma(7 forearms;2.0%).CONCLUSION Endoscopic fasciotomy for CECS of the forearm has favorable short-and midterm outcomes with very low recurrence and complication rates.This,however,needs to be confirmed in larger,long-term follow-up,prospective,comparative studies between open,mini-open and endoscopic fasciotomy techniques.

Symptomatic accessory soleus muscle:A cause for exertional compartment syndrome in a young soldier:A case report

BACKGROUND Accessory soleus muscle(ASM)is a rare congenital variation that is almost asymptomatic,but several papers have recently described symptomatic ASM.The clinical features of this condition are similar to tarsal tunnel syndrome(TTS)and include pain and numbness around the medial side of the ankle.ASM commonly originates from the fibula or soleus muscle and inserts into the Achilles tendon or calcaneus.Usually,it is identified as posteromedial swelling and definitely diagnosed by magnetic resonance imaging.In most cases,treatment is observation,but surgical excision can be considered if symptoms are severe.CASE SUMMARY A 23-year-old male Korean soldier presented with complaints of bilateral foot and ankle pain and a swelling medial to the Achilles tendon that was more pronounced on the right side.Symptoms first occurred after playing soccer 10 mo before this presentation,worsened after physical exertion,and were relieved by rest.He had no medical history,and no one in his family had the condition.Laboratory results were non-specific.Several tests were performed to exclude common diseases such as tumors or TTS.However,MRI revealed a bulky accessory soleus muscle in both feet,though the patient complained of more severe pain on the right side during physical activity.Accordingly,surgical resection was adopted.At surgery,a large accessory soleus muscle was noted anterior to the Achilles tendon with distinctive insertion from a normal soleus muscle.At 12 mo after surgery,there was no pain,numbness,or swelling of the right foot or ankle,no evidence of recurrence,and the patient could do all sports activities.CONCLUSION Accessory soleus muscle should be added to the list of differential diagnosis if a patient has pain,sole numbness or swelling of the posteromedial ankle.

Spatial Social Network Analysis: Program Pengembangan Usaha Agribisnis Perdesaan (PUAP) or an Exertion Development Program in Supporting the Region Revitalization Development

As the exertion development (PUAP) develop in Rejang Lebong Regency in Bengkulu province which had been started since 2008 by giving a kind of fund aid called Bantuan Langsung Masyarakat (BLM PUAP), to Gapoktan (Gabungan Kelompok Tani) or an organization of farmers such by giving some money as the capital used for 1) food plant cultiva-tion, horticulture, animal husbandry, plantation, and2) non-cultivation exertion such as;home industry of agriculture, small marketing scale and another agriculture exertion. By the approach which had been done is hoped to get the important result, on the other way the role of analysis factor (Social Network Analysis) from all undertaking stakeholders programs PUAP to be relevance steps aimed to understand the relation or connectivity from all factors in the network and also the role of factor inside the network itself be the relevance steps in arranging the strategy and work intention from the realization stage of PUAP program for the continuity of the realization program in the future (finding the good strategy) which aimed to develop the program of PUAP in Rejang Lebong Regency in Bengkulu Province, and to be a reference from doing the program as a national program in Indonesia.

Whole Body Vibration:The Effect of Position and Frequency on Perceived Exertion in Healthy,Active Adults

Whole Body Vibration(WBV)is a new exercise trend in fitness and performance enhancement.WBV platforms oscillate over a range of frequencies and amplitudes;however no study to date has examined the experience of perceived exertion with differences in vibration frequency and static or dynamic body position,nor examined the difference between sexes based on position and frequency during WBV.The purpose of this study was to assess the effects of position and frequency on perceived exertion during WBV in healthy,active adults.A convenience sample of 39 healthy young adults who participated in moderated exercise was blinded and randomly allocated to six WBV conditions composed of different frequency and position combinations.The participants received instruction,provided informed consent,participated in a warm-up session,and then reported rating of perceived exertion for each WBV condition.A 2×3 within-subjects multivariate approach ANOVA was conducted against an alpha of 0.05.A statistically significant main effect of position(p=0.004)and significant main effect of frequency(p=0.025)were found.Significant marginal means were found between the frequencies of 0 Hz and 50 Hz(p=0.007).Statistically significant differences were found between sexes for all combinations.

An unusual case of chest pain and dyspnea on exertion

Congenital coronary artery anomalies occur in less than 1% of the general population with clinical consequences ranging from benign incidental findings to sudden cardiac death. More often than not this diagnosis is made on a postmortem examination but up to one third of the patients have symptoms such as exertional chest pain and dyspnea. Due to the correctable nature of this entity and the fact that anomalous origins of coronary arteries can be readily diagnosed by noninvasive cardiac imaging modalities, timely clinical suspicion based on symptoms is critical. We present a case of a 37 years old with exertional chest pain and dyspnea of several years duration who was found to have an anomalous origin of the left main coronary artery. A surgical correction was undertaken which resulted in resolution of his symptoms. Our case highlights the importance of keeping congenital coronary anomalies on the differential diagnosis for exertional chest pain and dyspnea in young individuals and following inconclusive noninvasive testing with more definitive diagnostic modalities.

Risk factors for brain injury in patients with exertional heatstroke:A 5-year experience

Purpose:Minimal data exist on brain injury in patients with exertional heatstroke(EHS)in developing country.In this study,we explored the risk factors for brain injury induced by EHS 90-day after onset.Methods:A retrospective cohort study of patients with EHS was conducted in the intensive care unit of the General Hospital of Southern Theater Command of PLA in China from April 2014 to June 2019.Patients were divided into non-brain injury(fully recovered)and brain injury groups(comprising deceased patients or those with neurological sequelae).The brain injury group was further subdivided into a death group and a sequela group for detailed analysis.General information,neurological performance and information on important organ injuries in the acute stage were recorded and analysed.Multivariable logistic regression was used to identify risk factors for brain injury after EHS and mortality risk factors for brain injury,and Kaplan-Meier survival curve was used to evaluate the effect of the neurological dysfunction on survival.Results:Out of the 147 EHS patients,117 were enrolled,of which 96(82.1%)recovered,13(11.1%)died,and 8(6.8%)experienced neurological sequelae.Statistically significant differences were found between non-brain injury and brain injury groups in age,hypotension,duration of consciousness disorders,time to drop core body temperature below 38.5℃,lymphocyte counts,platelet counts,procalcitonin,alanine aminotransferase,aspartate aminotransferase,creatinine,cystatin C,coagulation parameters,international normalized ratio,acute physiology and chronic health evaluation II scores,sequential organ failure assessment(SOFA)scores,and Glasgow coma scale scores(all p<0.05).Multivariate logistic regression showed that age(OR=1.090,95%CI:1.02-1.17,p=0.008),time to drop core temperature(OR=8.223,95%CI:2.30-29.40,p=0.001),and SOFA scores(OR=1.676,95%CI:1.29-2.18,p<0.001)are independent risk factors for brain injury induced by EHS.The Kaplan-Meier curves suggest significantly prolonged survival(p<0.001)in patients with early Glasgow coma scale score>8 and duration of consciousness disorders≤24 h.Conclusions:Advanced age,delayed cooling,and higher SOFA scores significantly increase the risk of brain injury post-EHS.These findings underscore the importance of rapid cooling and early assessment of organ failure to improve outcomes in EHS patients.

Study on the Correlation between IL-6,SAA,CRP and Exertional Heat Stroke in Rats

Objective:To investigate the correlation between interleukin-6(IL-6),serum amyloid A(SAA),C-reactive protein(CRP)and exertional heat stroke in rats.Methods:A total of 90 adult Sprague-Dawley rats without specific pathogens were randomly divided into three groups:control group,classical group and exertion group,with 30 rats in each group.The control group was maintained at a temperature of(26±1)℃and humidity of(60±5)%,while the classical and exertion groups were exposed to a temperature of(40±0.5)℃and humidity of(70±5)%.Additionally,the exertion group underwent treadmill running under these conditions.The levels of IL-6,SAA,and CRP in the three groups were assessed and compared at various time points:before modeling,immediately after onset,and at 2,4,and 8 h after onset.Furthermore,Spearman correlation analysis was employed to examine.Results:The findings from the repeated measures analysis of variance indicated significant variations in the levels of IL-6,SAA,and CRP across the three groups(P<0.05).Both the classic and exertion groups exhibited higher levels of IL-6,SAA,and CRP compared to the control group,with the exertion group demonstrating even higher levels than the classic group(P<0.05).Additionally,Spearman correlation analysis revealed a positive correlation between the onset of heat stroke and the levels of IL-6,SAA,and CRP at the onset,as well as at 2,4,and 8 h post-onset(P<0.05).Furthermore,the types of heat stroke were found to be positively correlated with the levels of IL-6,SAA and CRP(P<0.05).Conclusion:The initiation and nature of heat stroke in rats are significantly associated with the concentrations of IL-6,SAA,and CRP.The concentrations of IL-6,SAA,and CRP within 8 h of onset can reliably forecast the occurrence of heat stroke in rats,serving as a basis for distinguishing classical heat stroke from exertional heat stroke.Nevertheless,the predictive and differentiating efficacy may diminish as the onset time prolongs.

Characteristics and Outcome of Exertional Heatstroke Patients Complicated by Acute Hepatic Injury:A Cohort Study

Background and Aims:Exertional heatstroke(EHS)is associated with strenuous physical activity in hot environments.The present study aimed to investigate dynamic changes of hepatic function indices in EHS patients and determine risk factors for death.Methods:This single-center retrospective cohort study considered all patients with EHS admitted to the intensive care unit at the General Hospital of Southern Theater Command of PLA from October 2008 to May 2019.Data on general characteristics,organ function parameters,and the 90-day outcome of enrolled patients were collected.Hepatic indices were collected dynamically,and patients with acute hepatic injury(AHI)were identified by plasma total bilirubin(TBIL)≥34.2μmol/L and an international normalized ratio≥1.5,or with any grade of hepatic encephalopathy.Results:In patients who survived,TBIL,alanine aminotransferase and aspartate aminotransferase were increased at 24 h,peaked at 2–3 days,and began to decrease at 5 days.In non-survivors,TBIL continuously increased post-admission.The area under the receiver operating characteristic curve for the prediction of mortality based on sequential organ failure assessment(SOFA)scores was 89.8%,and the optimal cutoff value was 7.5.Myocardial injury and infection were identified as independent risk factors for death in EHS patients with AHI.Conclusions:In EHS patients,hepatic dysfunction usually occurred within 24 h.Patients with AHI had more severe clinical conditions,and significantly increased 90-day mortality rates.SOFA scores over 7.5,complicated with myocardial injury or infection,were found to be risk factors for death in EHS patients with AHI.

Guasha improves the rating of perceived exertion scale score and reduces heart rate variability in male weightlifters:a randomized controlled trial

OBJECTIVE: To evaluate the effects of Guasha therapy on the rating of perceived exertion(RPE) scale score, and heart rate variability(HRV).METHODS: A randomized controlled trial of Guasha(skin scraping) was compared with a sham scraping group and control group. Sixteen sessions within an 8-week period were completed. Sixty-five male weightlifters who had undergone normal weightlifting training for a mean of 5 years before study commencement were recruited. The RPEscale score of "snatch", "clean and jerk" maneuvers(85% of one-repetition maximum), and HRV were measured before and after the intervention.RESULTS: The RPE scale score for snatch, clean and jerk were reduced significantly after intervention in the Guasha group and sham group. However, there was a significant difference in the low frequency(LF) domain and LF/high frequency(HF) ratio(P <0.05): the LF domain decreased, and the LF/HF ratio decreased.CONCLUSION: Guasha could be used to reduce the RPE scale score, and increase the response to HRV.Guasha could be considered as an alternative to some types of recovery from sports training.

Validity and reliability of a Chinese rating of perceived exertion scale in young Mandarin speaking adults

Background:The validity and reliability of the Borg 6–20 rating of perceived exertion(RPE)scale has not been tested among Chinese people from China' Mainland.The purpose of this study was to test:1)The validity of Leung Chinese version and Wang Chinese version of the Borg 6–20 RPE scale;2)The reliability of Wang Chinese version RPE scale;and 3)The agreement of these two Chinese versions of the RPE scale among young healthy adults from China' Mainland.Methods:A total of 26 subjects(11 males,15 females;age 22.7±3.0 yrs)volunteered to participate.They performed one(n=3),two(n=14),or three trials(n=9)of the Bruce treadmill protocol test within 9.0±5.1 days(validation trials),and 30.4±27.9 days(reliability trials).Power output,heart rate,oxygen consumption,and RPE were recorded.Results:RPE was significantly correlated with power output(Leung version rs≥0.75,Wang version rs≥0.73),heart rate(HR)(Leung version rs≥0.84,Wang version rs≥0.87),and oxygen consumption(VO2)(Leung version rs≥0.80,Wang version rs≥0.81)(all p<0.01).The overall test-retest interclass correlation was 0.94(p<0.01).No significant differences in correlations(RPE against power output,HR and VO_(2))between trials existed for the reliability tests of Wang version scale.No significant differences in correlations(RPE against power output,HR and VO_(2))between the two Chinese versions of RPE scale existed.Conclusion:Both Chinese RPE scales are valid among young healthy Chinese mandarin speaking adults.The Wang scale is reliable,and the Leung and Wang scales show superior agreement with each other.

Calculatons of the Electron Radius

Equating the Rest Mass Energy of a free electron to its Rest Charge Energy we prove that the electron cannot be a dimensionless point particle because if it were dimensionless, it would contain an infinite amount of Rest Charge Energy at the location of its charge since r = 0 gives , which is clearly not possible. Since the electron has no internal structure, equating its Rest Mass Energy to its Rest Charge Energy, we calculate the electron to be a sphere of radius 4.68 × 10-16 meters. We calculate the Electric Field at the surface of the electron due to its charge and the Repulsive Force two electrons in proximity exert on each other.

Exercise Intolerance and Excessive Chronotropic Response Due to Possible Autonomic Dysfunction Post COVID-19 Infection

Introduction and Objectives: In patients with Post-Acute Sequelae of Coronavirus 2 infection (PASC), a post infectious autonomic dysfunction may be one of the underlying mechanisms. Patients often present with exercise intolerance and exaggerated heart rate response to exercise. We report a single centre experience of patients with PACS and suspected autonomic dysfunction. Methods: Forty-two patients evaluated in the Outpatient Cardiology Department with suspected PASC were included in the study. Patients complained of compromised exercise performance persisting >3 months after recovery from COVID-19 infection, compared to the pre-COVID-19 period. The patients were evaluated with 12-lead electrocardiogram, echocardiography, 24-hour ECG ambulatory monitoring and either exercise stress test or a 6-minute walk test. Results: All 42 patients demonstrated an exaggerated chronotropic response, defined as the inappropriate increase in heart rate before the 6th minute of exercise >100% of the age-predicted maximal heart rate value with reproduction of clinical symptoms. In addition, 24-hour ambulatory electrocardiography revealed an increased mean heart rate of 92 beats/minute and decreased mean standard deviation of sequential 5-minute N-N interval (SDNN) of 74.4 ms. Pharmaceutical treatment with b-blockers, ivabradine or both was administrated in 29 (69%) resulting in symptomatic improvement in 82.8% of those under treatment. However, residual symptoms persisted in 69% of patients after 3 months. Conclusions: In patients with “Post-acute COVID-19” syndrome, we found an excessive chronotropic response to exercise suggesting autonomic dysfunction as the underlying mechanism of symptoms. Treatment with beta blockers or ivabradine resulted in clinical improvement but a substantial proportion of patients remained symptomatic.