The "Extreme Exercise Hypothesis": Recent Findings and Cardiovascular Health Implications

Cardiac function and autonomic cardiac function during a multi-stage cycling event: a brief report

Introduction

Prolonged and repeated exercise performed during an ultra-endurance event can induce general and cardiac fatigue known as exercise-induced cardiac fatigue. Our objective was to find a possible correlation between the cardiac function and the autonomic cardiac function.

Methods

During a multistage ultra-endurance event, a female well-trained cyclist underwent daily rest echocardiography and heart rate variability measurements to assess the cardiac function and the cardiac autonomic function.

Results

The athlete completed 3,345 km at 65% of her maximum heart rate and 39% of her maximum aerobic power. A progressive improvement of the systolic function for both the left ventricle and the right ventricle was observed during the event.

Discussion

Alterations were observed on the cardiac autonomic function with an imbalance between sympathetic and parasympathetic, but there was no sign of a significant correlation between the cardiac function and the autonomic cardiac function and no signs of cardiac fatigue either. Further analysis should be performed on a larger sample to confirm the obtained results.

Outrunning the grim reaper: longevity of the first 200 sub-4 min mile male runners

OBJECTIVES

To determine the impact of running a sub-4 min mile on longevity. It was hypothesised that there would be an increase in longevity for runners who successfully completed a sub-4 min mile compared with the general population.

METHODS

As part of this retrospective cohort study, the Sub-4 Alphabetic Register was used to extract the first 200 athletes to run a sub-4 min mile. Each runner's date of birth, date of their first successful mile attempt, current age (if alive) or age at death was compared with the United Nations Life Tables to determine the difference in each runner's current age or age at death with their country of origin-specific life expectancy.

RESULTS

Of the first 200 sub-4 min mile runners (100% male), 60 were dead (30%) and 140 were still alive. Sub-4 min mile runners lived an average of 4.7 years beyond their predicted life expectancy (95% CI 4.7 to 4.8). When accounting for the decade of completion (1950s, 1960s or 1970s), the longevity benefits were 9.2 years (n=22; 95% CI 8.3 to 10.1), 5.5 years (n=88; 95% CI 5.3 to 5.7) and 2.9 years (n=90; 95% CI 2.7 to 3.1), respectively.

CONCLUSION

Sub-4 min mile runners have increased longevity compared with the general population, thereby challenging the notion that extreme endurance exercise may be detrimental to longevity.

Cardiomyocyte Adaptation to Exercise: K+ Channels, Contractility and Ischemic Injury

Cardiovascular disease is a leading cause of morbidity and mortality, and exercise-training (TRN) is known to reduce risk factors and protect the heart from ischemia and reperfusion injury. Though the cardioprotective effects of exercise are well-documented, underlying mechanisms are not well understood. This review highlights recent findings and focuses on cardiac factors with emphasis on K+ channel control of the action potential duration (APD), β-adrenergic and adenosine regulation of cardiomyocyte function, and mitochondrial Ca2+ regulation. TRN-induced prolongation and shortening of the APD at low and high activation rates, respectively, is discussed in the context of a reduced response of the sarcolemma delayed rectifier potassium channel (IK) and increased content and activation of the sarcolemma KATP channel. A proposed mechanism underlying the latter is presented, including the phosphatidylinositol-3kinase/protein kinase B pathway. TRN induced increases in cardiomyocyte contractility and the response to adrenergic agonists are discussed. The TRN-induced protection from reperfusion injury is highlighted by the increased content and activation of the sarcolemma KATP channel and the increased phosphorylated glycogen synthase kinase-3β, which aid in preventing mitochondrial Ca2+ overload and mitochondria-triggered apoptosis. Finally, a brief section is presented on the increased incidences of atrial fibrillation associated with age and in life-long exercisers.

Ethnic Differences in Survival among Brazilian Modern-era Olympic Medalists from 1920 to 1992: A Cohort Study

BACKGROUND

Disparities in health outcomes among racial groups warrant investigation, even among elite athletes. Therefore, understanding the impact of race upon post-medal survival in Brazilian Olympians becomes essential.

OBJECTIVE

To compare post-medal survival between white and non-white Brazilian Olympic medalists from 1920 to 1992.

METHODS

This study used publicly available data for a retrospective cohort study on all Brazilian Olympic medalists from 1920 to 1992 (males only). Athletes were classified into white and non-white groups using structured ethnicity determination. Kaplan-Meier analyses computed the restricted mean survival time (RMST) for each ethnic group. A Cox proportional hazards analysis assessed ethnicity-based survival differences, adjusting for medal-winning age and birth year (p<0.05).

RESULTS

Among 123 athletes (73.9% white), the mean age of medal achievement was 25.03±4.8 years. During the study, 18.7% of white and 37.5% of non-white athletes died (p=0.031). White athletes had a mean age at death of 75.10±18.01 years, while non-white athletes had an age of 67.13±14.90 years (p=0.109). The RMST for white athletes was 51.59 (95% CI 49.79-53.39) years, while for non-white athletes, it was 45.026 (95% CI 41.31-48.74) years, resulting in a ΔRMST of 6.56 (95% CI 2.43-10.70; p=0.0018). Multivariate analysis showed that non-white athletes had a higher mortality risk than did white athletes (HR 5.58; 95% CI, 2.18-14.31).

CONCLUSION

Following their first medal, white Brazilian Olympians typically enjoy a six-year longer lifespan than their non-white counterparts, illustrating a marked mortality gap and health disparities among healthy individuals in Brazil.

Relationships of Total and Domain-Specific Moderate-to-Vigorous Physical Activity with All-Cause and Disease-Specific Mortality

PURPOSE

This study aimed to investigate the relationships of moderate-to-vigorous physical activity (MVPA) with all-cause and disease-specific mortality. We also investigated how the association between MVPA at leisure time (LT-MVPA) and health outcomes differs at different MVPA at work (WT-MVPA) levels.

METHODS

The 81,601 community-dwelling Japanese persons age 50-79 yr who responded to a questionnaire in 2000-2003 were followed until 2018. Cox proportional hazard model was used to examine the association of total MVPA with risks of all-cause, cancer, heart disease, stroke, and respiratory disease mortality. Then, we compared the mortality risk according to the tertile of LT-MVPA, stratified by the tertile of WT-MVPA.

RESULTS

During the 15.1 yr of average follow-up, 16,951 deaths were identified. Even total MVPA below the recommended volume (i.e., 0.1-1.49 MET·h·d -1 ) was associated with 11% to 24% reductions in all-cause (hazard ratio [HR], 0.89; 95% confidence interval [CI], 0.82-0.96) and heart disease mortality (HR, 0.76; 95% CI, 0.61-0.94), compared with no MVPA at all. The further reduced risks were seen in MVPA up to 10 MET·h·d -1 . The inverse association between LT-MVPA and mortality risks was more evident at lower WT-MVPA, which was also inversely associated with the risks.

CONCLUSIONS

Health benefits were observed at low levels of MVPA and up to 10 MET·h·d -1 , although the fine threshold for excessive MVPA was not clear. LT-MVPA had distinct health benefits especially for persons with lower WT-MVPA.

Atrial fibrillation catheter ablation in endurance athletes: systematic review and meta-analysis

BACKGROUND

Atrial fibrillation (AF) management in endurance athletes (EA) is challenging due to the paucity of data, especially on the efficacy and safety of catheter ablation (CA). The hypothesis is that the efficacy and safety of AF CA in EA are comparable to the non-EA.

METHODS

Databases from EMBASE, Medline, PubMed, and Cochrane were searched from inception through February 2023. Studies with available information on efficacy and safety profiles were included. Effect estimates from the individual studies were extracted and combined using random effect and generic inverse variance method of DerSimonian and Laird.

RESULTS

Nine observational studies with a total of 1129 participants were identified, of whom 51% were EA. Our analysis found that rate of atrial arrhythmia (AA) recurrences following AF CA was not statistically different between EA and non-EA (RR 1.04, I2 = 57.6%, p = 0.54). The AA survival rates after a single ablation in EA was 60.2%, which improved up to 77% after multiple ablations during the follow-up period. Infrequent complication rates ranging from 0 to 7.6% were observed, with no mortality.

CONCLUSIONS

Our meta-analysis suggests that AF CA is as effective and safe in EA as in non-EA. In the future, AF CA should be considered as a first-line therapeutic choice in this patient group.

Physical Exercise After Solid Organ Transplantation: A Cautionary Tale

An increasing body of randomized controlled trials suggests the safety of engaging in moderate to vigorous intensity exercise training following solid organ transplantation. Fueled by emerging sport events designed for transplant recipients and the ever-growing body of research highlighting the diverse health benefits of physical activity, transplant recipients are now increasingly participating in strenuous and occasionally competitive physical endeavors that largely surpass those evaluated in controlled research settings. This viewpoint article adopts a cautionary stance to counterbalance the prevalent one-sided optimistic perspective regarding posttransplant physical activity. While discussing methodological limitations, we explore plausible adverse impacts on the cardiovascular, immunological, and musculoskeletal systems. We also examine the physiological consequences of exercising in the heat, at high altitude, and in areas with high air pollution. Risks associated with employing performance-enhancing strategies and the conceivable psychological implications regarding physical activity as a tribute to the 'gift of life' are discussed. With a deliberate focus on the potential adverse outcomes of strenuous posttransplant physical activity, this viewpoint aims to restore a balanced dialogue on our comprehension of both beneficial and potentially detrimental outcomes of physical activity that ultimately underscores the imperative of well-informed decision-making and tailored exercise regimens in the realm of posttransplant care.

Vigorous physical activity and atrial fibrillation in healthy individuals: What is the correct approach?

Sport activity compared to sedentary life is associated with improved wellbeing and risk reduction in many different health conditions including atrial fibrillation (AF). Vigorous physical activity is associated with increased AF risk. We describe four individuals, who regularly perform endurance sport activity and developed AF. We discuss the changes occurring in the heart of endurance athletes and the possible etiology for AF, as well as currently available treatment options in this seemingly healthy population. Although the etiology of AF in the general population differs from the one in the usually younger endurance sport activity population, the treatment options are similar. There are several factors unique to those involved in vigorous physical activity that can influence their management. Despite a lack of evidence, endurance athletes with AF have traditionally been advised to "de-training," to reduce both the amount and intensity of exercise. Some of the current offered treatment options (beta-blockers, class III antiarrhythmic) have a varied range of adverse effect, hindering them unattractive for these individuals. Depending on risk stratification tools, anticoagulation may be indicated. Some suggest an intermittent dosing therapy, while others recommend following current guidelines. AF ablation is recommended in exercising individuals with recurrent, symptomatic AF and/or in those who do not want drug therapy, given its impact on athletic performance, AF treatment decisions should be individualized for those engaging vigorous physical activity, while considering the potential risks, the urgency of returning to training, and the will and expectations of the patient.

Changes in the chronic and postprandial blood lipid profiles of trained competitive cyclists and triathletes following a ketogenic diet: a randomized crossover trial

BACKGROUND

The ketogenic diet (KD) is the most popular carbohydrate restriction strategy for endurance athletes. However, because the primary goal of employing the KD is to gain a competitive advantage in competition, endurance athletes may be less concerned with the influence of the KD on their cardiometabolic health; particularly their blood lipid profiles. Thus, the purpose of this study was to examine the chronic and postprandial blood lipid alterations following a two-week ad libitum KD compared to an ad libitum high-carbohydrate diet (HCD) and the athletes' habitual diet (HD) in a group of trained competitive cyclists and triathletes.

METHODS

Six trained competitive cyclists and triathletes (female: 4, male: 2; age: 37.2 ± 12.2) completed this randomized crossover trial, which required them to follow a two-week ad libitum KD and HCD in a randomized order after their HD. Fasting blood lipids were collected following their HD and after two-weeks of the KD and HCD conditions. Postprandial blood lipid responses to a test meal reflective of the assigned diet were collected at the end of each diet condition.

RESULTS

Fasting total cholesterol (TC) was significantly higher following the KD compared to the HD (p < 0.001) and HCD (p = 0.006). Postprandial incremental area under the curve for triglycerides (TRG), TRG:HDL ratio, and VLDL-C were significantly higher following the KD test meal compared to the HD (all p < 0.001) and HCD (all p = 0.001) test meals but LDL-C and LDL:HDL ratio were significantly lower following the KD compared to the HD and HCD test meals (all p < 0.001).

CONCLUSIONS

Trained competitive cyclists and triathletes demonstrate increased TC in response to a two-week KD compared to a HCD or HD. Endurance athletes contemplating a KD should consider the potential for these blood lipid alterations, and future research should focus on postprandial blood lipid responses to determine if these changes manifest in chronic blood lipid shifts.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04097171 (11 October 2019).

Exercise-Induced Fluid Retention, Cardiac Volume Overload, and Peripheral Edema in Ultra-Distance Cyclists

Introduction

Ultracyclists expose themselves to extreme physical challenges. This study aimed to elucidate the effects of ultracycling on electrolyte and fluid balance and investigate the potential occurrence of peripheral edema.

Methods

A total of 4 clinical visits were performed before, during, and after a 6-day bicycle ride in 13 ultracyclists (5 female, 8 male) including serial laboratory analyses of blood and urine, bioelectrical impedance, and echocardiography. Throughout the ride, participants continuously tracked fluid intake, measured extremity circumferences daily, and self-tested urinary electrolytes using a point-of-care testing device. Portrait photos were judged by 20 physicians for occurrence of facial and eyelid edema.

Results

Participants covered a mean distance of 1205 km and 19,417 vertical meters. From baseline to day 6, body weight remained stable (P = 0.479); however, body composition changed with increasing total body water (TBW) (+1.98 l ± 1.37, P = 0.003) and plasma volume (+18.86 % ± 10.7, P < 0.001). A significant increase in N-terminal pro brain natriuretic peptide (NT-proBNP) (+297.99 ng/l ± 190.42, P < 0.001) until day 6 indicates concomitant cardiac volume overload. Swelling of face and eyelids peaked on day 5 (both P ≤ 0.033). On recovery, changes partly resolved. Although urinary sodium concentration showed a nadir on day 4 (-32.18 mmol/l ± 23.88, P = 0.022), plasma osmolality (+5.69 mmosmol/kg ± 5.88, P = 0.004) and copeptin (+38.28 pg/ml ± 18.90, P < 0.001) increased steadily until day 6.

Conclusion

Ultracycling over multiple days induces extracellular volume expansion, peripheral edema, and cardiac volume overload. Renal sodium and water retention is likely contributing to this condition.

Cardiovascular risk and systemic inflammation in male professional rugby: a cross-sectional study

Objective

To investigate cardiovascular risk factors' prevalence and association with systemic inflammation in professional male rugby players (RP).

Methods

A cross-sectional investigation of 46 professional male RP (26.1±4.1 years) cardiovascular risk factors were compared by position. Inflammatory markers were compared with healthy controls (n=13) and patients with rheumatoid arthritis (RA) (n=10).

Results

Twenty-six per cent of RP had no risk factors, 49% had 1-2 cardiovascular risk factors and 25% had 3-4 risk factors. Forwards had greater body fat (p<0.001), visceral fat (p<0.001), glucose (p=0.025), and C reactive protein (CRP) (p=0.023) compared with backs. RP demonstrated more favourable lipid and glucose profiles than reference values for the general population. Most RP (n=28, 61%) had elevated blood pressure (≥140/90 mm Hg). RP had higher vascular adhesion molecule-1 (VCAM-1) (p=0.004) and intracellular adhesion molecule-1 (ICAM-1) (p=0.002) than healthy controls. RP had lower CRP than patients with RA (p=0.009), while one-third (n=15) displayed equivalent ICAM-1 and VCAM-1 levels. Multivariate clustering and principal component analysis biplots revealed higher triglycerides, inflammatory markers, and worse body composition were associated with forwards.

Conclusions

Despite athletic status, most of this rugby cohort had at least one cardiovascular risk factor. Concomitantly, these RP demonstrated increased levels of inflammation, with one-third, primarily forwards, displaying equivalent levels to patients with inflammatory disease. Further studies are needed to unravel the prognostic implications of increased inflammation in RP because unchecked, chronic inflammation may lead to increased cardiovascular disease risk.

Assoication between self-reported sleep duration, physcial activity and the risk of all cause and cardiovascular diseases mortality from the NHANES database

OBJECTIVE

The purpose of this study was to investigate the combined effect of self-reported sleep durations and physical activity (PA) on all cause and cardiovascular diseases mortality.

METHODS

Twenty-nine thousand fifty-eight participants (48.5% male, median age 49 years) from the National Health and Nutrition Examination Survey cycles 2007 to 2016 were included. We classified sleep duration into five categories (< 5.5 h/d,5.5-6.5 h/d,6.5-7.5 h/d,7.5-8.5 h/d, ≥ 8.5 h/d) and classified PA levels into three groups (high, medium and low). PA information and self-reported sleep duration were obtained by questionnaire. We derived 15 PA-sleep duration combinations. The primary endpoint was all-cause mortality, and the major secondary endpoint was cardiovascular diseases (CVD) mortality as of December 2022.

RESULTS

Median follow-up was 91 months. Compared with standard sleep duration (6.5-7.5 h/d), both shorter (< 5.5 h/d) and longer (≥ 8.5 h/d) sleep durations increased risks of all-cause mortality and CVD mortality in low PA. The deleterious associations of sleep duration with all outcomes was amplified by lower PA. There was no significant reduction in CVD mortality risk associated with increased physical activity during short sleep duration (< 6.5 h/d). During standard sleep, low PA significantly increased CVD mortality risk. At medium physical activity, both short and long sleep increased cardiovascular mortality. It was also found that sleep duration (≥ 8.5 h/d) was associated with a increase in all-cause and cardiovascular mortality at both low and high PA levels.

CONCLUSIONS

This study suggested that low PA significantly increased the association of self-reported long and short sleep durations with all-cause and CVD mortality. All cause mortality appears to benefit from medium physical activity, while medium PA did not. Physical activity did not significantly reduce the risk of CVD mortality.

Atrial Fibrillation in Endurance Training Athletes: Scoping Review

Background

Moderate regular physical activity is indicated to avoid atrial fibrillation (AF), whereas athletes should be counseled that long-lasting vigorous sports engagement may cause AF, according to the 2016 European Society of Cardiology (ESC) recommendations for AF treatment. Exercise and AF are complex.

Objectives

To evaluate the relationship between Endurance training and AF, in addition to the starting point/trigger by which Endurance Training causes impairment of cardiac function and AF, considering the time and intensity of Endurance training.

Materials and Methods

We synthesized evidence from articles published in the PubMed, EMBASE, and SciELO databases using their respective Boolean operators. A total of 112 original articles related to AF and endurance athletes published up to the year 2023 were reviewed.

Results

Our study verified multiples aspects of the genesis of AF in athletes, such as cardiac adaptations to exercise, disturbances in cardiac injury biomarkers, sex differences in cardiac adaptations and their role in AF risk, and the relationship between body composition (height, weight, and physical fitness) and AF pathogenesis.

Conclusions

Variations in cardiac structure (increased atrial thickness and size in addition to myocardial fibrosis) and significant increases in vagal tone (sinus bradycardia and imbalances in sympathetic and parasympathetic activation) shorten the refractory period shortening in athletes, induce the onset of re-entrance mechanisms, and serve as ectopic triggers that can lead to AF.

Exercise and COVID-19: exercise intensity reassures immunological benefits of post-COVID-19 condition

Any form of physical activity, including exercise, has various benefits at the physiological (improving cardiac and respiratory functions, increasing skeletal muscle mass, and maintaining homeostasis) and psychological levels (improving cognitive function, reducing anxiety and depression) which help to combat any type of infection. In contrast, the infectivity ratio could reduce the physical activity of an individual, such as performing a habitual exercise. Adaptation to different exercise strategies including intensity and duration may better increase physical performance and improve the symptoms. For example, low to moderate intensity perhaps fails to induce this adaptive process, while high-intensity of exercise compromises immune health. This can aggravate the infection rate (Open window theory). However, high intensity with a shorter time produces various morphological alterations in the primary organs including the lungs and heart, which facilitate life support in COVID-19 patients. However, less information about exercise protocols failed to assure the benefits of exercise to COVID-19 patients, particularly post-COVID-19 conditions. Therefore, this review will answer how exercise intensity is crucial to reassure the exercise benefits for promoting safe participation before infection and post-COVID-19 conditions.

Examining chronic disease onset across varying age groups of Indian adults using competing risk analysis

In low-and-middle-income countries, people develop chronic diseases at a younger age, leading to health-and-economic loss. Estimates of the age of onset of chronic disease provide evidence for policy intervention, but in the Indian context, evidence is limited. The present study aims to explore the onset of seven chronic diseases across adults and the elderly, along with the prognostic factors of chronic disease onset. Using Wave 1 data of the Longitudinal Ageing Study in India (LASI), we estimated the statistical distributions, the median age at onset, and Loglogistic and Weibull accelerated failure time model to understand the onset of seven medically diagnosed self-reported chronic diseases across age groups. We also obtained the sub-distribution hazard ratio (SHR) from the Fine-Gray model to determine the risk of contracting selected chronic diseases in a competing risk setup. The seven chronic diseases- hypertension, diabetes, lung disease, heart disease/stroke, arthritis, neurological disease, and cancer- were developing early, especially in individuals aged 45-54 and 55-64. Arthritis risk was higher in rural areas, and physically active adults and elderly were 1.32 times (95% CI 1.12-1.56) more likely to develop heart disease/stroke. The emerging evidence of the early onset of neurological diseases in middle-aged adults (i.e., among the 45-54 age group) reminds us of the need to reinforce a balance between the physical and mental life of individuals. The early onset of chronic diseases in the independent and working-age category (45-54 years) can have many social and economic implications. For instance, it can create a greater healthcare burden when these individuals grow older with these diseases. Further, disease-specific interventions would be helpful in reducing future chronic disease burden.

Premature Death in Bodybuilders: What Do We Know?

Premature deaths in bodybuilders regularly make headlines and are cited as evidence that bodybuilding is a dangerous activity. A wealth of research has revealed elite athletes typically enjoy lower mortality rates than non-athletes, but research on bodybuilder lifespan is surprisingly limited. Anabolic androgenic steroid (AAS) use is commonly cited as a key contributor to morbidity and premature mortality in bodybuilders, but this area of research is highly nuanced and influenced by numerous confounders unique to bodybuilding. It is quite possible that bodybuilders are at elevated risk and that AAS use is the primary reason for this, but there remains much unknown in this realm. As global participation in bodybuilding increases, and healthcare providers play a more active role in monitoring bodybuilder health, there is a need to identify how numerous factors associated with bodybuilding ultimately influence short- and long-term health and mortality rate. In this Current Opinion, we discuss what is currently known about the bodybuilder lifespan, identify the nuances of the literature regarding bodybuilder health and AAS use, and provide recommendations for future research on this topic.

Hypertrophic cardiomyopathy or athlete's heart? A systematic review of novel cardiovascular magnetic resonance imaging parameters

Hypertrophic cardiomyopathy (HCM) is a common cause of sudden cardiac death in athletes. Cardiac Magnetic Resonance (CMR) imaging is considered an excellent tool to differentiate between HCM and athlete's heart. The aim of this systematic review was to highlight the novel CMR-derived parameters with significant discriminative capacity between the two conditions. A systematic search in the MEDLINE, EMBASE and Cochrane Reviews databases was performed. Eligible studies were considered the ones comparing novel CMR-derived parameters on athletes and HCM patients. Therefore, studies that only examined Cine-derived volumetric parameters were excluded. Particular attention was given to binary classification results from multi-variate regression models and ROC curve analyses. Bias assessment was performed with the Quality Assessment on Diagnostic Accuracy Studies. Five (5) studies were included in the systematic review, with a total of 284 athletes and 373 HCM patients. Several novel indices displayed discriminatory potential, such as native T1 mapping and T2 values, LV global longitudinal strain, late gadolinium enhancement and whole-LV fractal dimension. Diffusion tensor imaging enabled quantification of the secondary eigenvalue angle and fractional anisotropy in one study, which also proved capable of reliably detecting HCM in a mixed athlete/patient sample. Several novel CMR-derived parameters, most of which are currently under development, show promising results in discerning between athlete's heart and HCM. Prospective studies examining the discriminatory capacity of all promising modalities side-by-side will yield definitive answers on their relative importance; diagnostic models can incorporate the best performing variables for optimal results.

Prevention of Sudden Death in Sports: A Global and Multidisciplinary Observatory for Scientific Research and Knowledge Transfer (PREMUBID)

Background

The health benefits of sports and exercise training are well known. However, an acute bout of exercise transiently increases the risk of sudden cardiac death (SCD). To minimize the cardiovascular risks of exercise, more insight into the prevention and causes of SCD is needed.

Methods

The observatory for the prevention of sudden death in sports, PREMUBID, was created with the aim of fostering research to assess the benefits and risks of exercise at different volumes and intensities and to get insight into the underlying mechanisms of potentially cardiac (mal) adaptations.

Results

The observatory gathers researchers from a wide range of disciplines working at institutions in Europe and North America. The guiding principles of PREMUBID are to broaden the understanding of SCD in sports, strengthening collaborative research across the globe, and to develop, implement and evaluate robust pre-participation screening and emergency care strategies to further reduce the number of fatal cardiac events in sport events. During the inaugural meeting of the observatory, members and affiliated researchers discussed possibilities to initiate collaborative research projects and to exchange staff and students to share information and practices to prevent SCD. The final goal is to translate the obtained knowledge to understandable messages for the general population and healthcare workers to ensure that the population at large benefits from it.

Conclusions

The PREMUBID consortium aims to produce novel knowledge and insights in SCD prevention, in order to maximize the health benefits associated with acute and long-term exercise training.

100 Long-Distance Triathlons in 100 Days: A Case Study on Ultraendurance, Biomarkers, and Physiological Outcomes

The physical demands of a single long-distance triathlon (LDT) are sufficient to cause robust physiological perturbations. In this unique case study, an ultraendurance athlete completed 100 LDTs in 100 days (100LDT).

PURPOSE

This study aims to describe and analyze this single athlete's performance, physiological biomarkers, and sleep parameters throughout the 100LDT.

METHODS

An ultraendurance athlete completed an LDT (2.4-mile swim, 112-mile bike ride, and 26.2-mile marathon) each day for 100 consecutive days. Physical work, physiological biomarkers, and sleep parameters were recorded each night using a wrist-worn photoplethysmographic sensor. Clinical exercise tests were performed before and after the 100LDT. Time-series analysis assessed changes in biomarkers and sleep parameters across the 100LDT, and cross-correlations considered the associations between exercise performance and physiological metrics at varying time lags.

RESULTS

The swim and cycling performances varied across the 100LDT, while the run was relatively stable. Resting heart rate, heart-rate variability, oxygen saturation, sleep score, light sleep, sleep efficiency, and sleep duration were all best characterized by cubic models. Additional post hoc subanalyses suggest that the first half of the 100LDT most influenced these dynamics.

CONCLUSIONS

The 100LDT resulted in nonlinear alterations to physiological metrics. This world record was a unique event but allows valuable insights into the limits of human endurance performance.

Exercise Training and Verbena officinalis L. Affect Pre-Clinical and Histological Parameters

Verbena officinalis L. or vervain is an herbal medicine and dietary supplement used worldwide. It is used for antidepressant and anticonvulsant purposes, as well as to treat inflammatory disorders, skin burns, abrasions, and gastric diseases, among others. Here, we investigated the biochemical, antioxidant, and histopathological effects of vervain against chronic physical stress. Male Wistar rats were submitted to chronic physical training and oral administration of 200 mg/kg of extract for 7 weeks. Control animals were not treated with either stress or vervain. Body weight was monitored during the study. Liver, kidney, spleen, testis, epididymis, heart, skeletal muscle, and brain samples were collected. Blood cholesterol, lactate dehydrogenase (LDH), bilirubin, and creatinine kinase (CREA), among others, were studied. Glutathione peroxidase (GPox) and superoxide dismutase (SOD) antioxidant activity was analyzed in the blood, liver, and kidney. Testosterone measurements were also performed on whole testis extracts. We found significant weight ratios differences in the epididymis, brain, and heart. Animals submitted to training showed hemorrhagic livers. Kidney histology was affected by both stress and vervain. Cell disruption and vacuolization were observed in the testes and epididymis of animals submitted to stress. Hematological and biochemical markers as CREA, LDH, TP, CKI, URCA, γGT, and glucose revealed statistically significantly differences. Additionally, the activity of glutathione peroxide (GPox) and superoxide dismutase (SOD) in the blood was also impacted. Both stress and vervain have significant in vivo effects. Infusions of vervain include phenylpropanoids, iridoids, verbenalin, hastatoside, and flavonoids, amongst others, which interact synergistically to produce the preclinical effects reported here.

Endurance training-induced cardiac remodeling in a guinea pig athlete's heart model

Besides the health benefits of regular exercise, high-level training-above an optimal level-may have adverse effects. In this study, we investigated the effects of long-term vigorous training and its potentially detrimental structural-functional changes in a small animal athlete's heart model. Thirty-eight 4-month-old male guinea pigs were randomized into sedentary and exercised groups. The latter underwent a 15-week-long endurance-training program. To investigate the effects of the intense long-term exercise, in vivo (echocardiography, electrocardiography), ex vivo, and in vitro (histopathology, patch-clamp) measurements were performed. Following the training protocol, the exercised animals exhibited structural left ventricular enlargement and a significantly higher degree of myocardial fibrosis. Furthermore, resting bradycardia accompanied by elevated heart rate variability occurred, representing increased parasympathetic activity in the exercised hearts. The observed prolonged QTc intervals and increased repolarization variability parameters may raise the risk of electrical instability in exercised animals. Complex arrhythmias did not occur in either group, and there were no differences between the groups in ex vivo or cellular electrophysiological experiments. Accordingly, the high parasympathetic activity may promote impaired repolarization in conscious exercised animals. The detected structural-functional changes share similarities with the human athlete's heart; therefore, this model might be useful for investigations on cardiac remodeling.

Exercise as an Aging Mimetic: A New Perspective on the Mechanisms Behind Exercise as Preventive Medicine Against Age-Related Chronic Disease

Age-related chronic diseases are among the most common causes of mortality and account for a majority of global disease burden. Preventative lifestyle behaviors, such as regular exercise, play a critical role in attenuating chronic disease burden. However, the exact mechanism behind exercise as a form of preventative medicine remains poorly defined. Interestingly, many of the physiological responses to exercise are comparable to aging. This paper explores an overarching hypothesis that exercise protects against aging/age-related chronic disease because the physiological stress of exercise mimics aging. Acute exercise transiently disrupts cardiovascular, musculoskeletal, and brain function and triggers a substantial inflammatory response in a manner that mimics aging/age-related chronic disease. Data indicate that select acute exercise responses may be similar in magnitude to changes seen with +10-50 years of aging. The initial insult of the age-mimicking effects of exercise induces beneficial adaptations that serve to attenuate disruption to successive "aging" stimuli (i.e., exercise). Ultimately, these exercise-induced adaptations reduce the subsequent physiological stress incurred from aging and protect against age-related chronic disease. To further examine this hypothesis, future work should more intricately describe the physiological signature of different types/intensities of acute exercise in order to better predict the subsequent adaptation and chronic disease prevention with exercise training in healthy and at-risk populations.

Working Out: The Molecular Biology of Exercise

The many health benefits of exercise are well-known. Conversely, the pathologies associated with a sedentary lifestyle are also well-documented. However, science and medicine have only recently begun to explain how exercise does what it does. Here, I discuss recent insight into the biochemical mechanisms underlying the benefits of exercise and the pathologies of inactivity.

Extracellular Inflammasome Particles Are Released After Marathon Running and Induce Proinflammatory Effects in Endothelial Cells

Objectives: The intracellular NLRP3 inflammasome is an important regulator of sterile inflammation. Recent data suggest that inflammasome particles can be released into circulation. The effects of exercise on circulating extracellular apoptosis-associated speck-like protein (ASC) particles and their effects on endothelial cells are not known.

Methods: We established a flow cytometric method to quantitate extracellular ASC specks in human serum. ASC specks were quantitated in 52 marathon runners 24–72 h before, immediately after, and again 24–58 h after the run. For mechanistic characterization, NLRP3 inflammasome particles were isolated from a stable mutant NLRP3 (p.D303N)-YFP HEK cell line and used to treat primary human coronary artery endothelial cells.

Results: Athletes showed a significant increase in serum concentration of circulating ASC specks immediately after the marathon (+52% compared with the baseline, p < 0.05) and a decrease during the follow-up after 24–58 h (12% reduction compared with immediately after the run, p < 0.01). Confocal microscopy revealed that human endothelial cells can internalize extracellular NLRP3 inflammasome particles. After internalization, endothelial cells showed an inflammatory response with a higher expression of the cell adhesion molecule ICAM1 (6.9-fold, p < 0.05) and increased adhesion of monocytes (1.5-fold, p < 0.05).

Conclusion: These findings identify extracellular inflammasome particles as novel systemic mediators of cell–cell communication that are transiently increased after acute extensive exercise with a high mechanical muscular load.

Improvement of Sympathovagal Balance by Regular Exercise May Counteract the Ageing Process. A Study by the Analysis of QT Variability

QT interval (QT) variability analysis provides pathophysiological and prognostic information utilized in cardiac and non-cardiac diseases, complementary to those obtained from the analysis of heart period (HP) variability. An increased QT variability has been associated to a higher risk for cardiac events and poorest prognosis. Autonomic cardiovascular adaptation to internal and external challenges, such those occurring in athletes exposed to high levels of physical stress and in ageing could also be deepen by analyzing QT variability, searching for early prognostic signatures. The aim of the study was to analyze the QT variability and cardiac control complexity in a group of middle-aged half-marathon runners at baseline (B) and at a 10-year follow-up (FU). We found that the overall QT variability decreased at FU, despite the inescapable increase in age (52.3 ± 8.0 years at FU). This change was accompanied by an increase of the HP variability complexity without changes of the QT variability complexity. Of notice, over the years, the group of athletes maintained their regular physical activity by switching to a moderate intensity rather than strenuous. In conclusion, regular and moderate exercise over the years was beneficial for this group of athletes, as reflected by the decreased overall QT variability that is known to be associated to lower cardiovascular risk. The concomitant enhanced cardiac control complexity also suggests a trend opposite to what usually occurs with ageing, resulting in a more flexible cardiac control, typical of younger people.

Cardiovascular Disease Risk Profiles in Indonesian Athletes

BACKGROUND: Notwithstanding how physical exercise lessens cardiovascular and all-cause mortality, young and active athletes might have cardiovascular risk factors or fundamental cardiovascular diseases (CVDs), putting them at increased risk for sudden cardiac death during times of strenuous exercise. AIM: The study aimed to assess the cardiovascular risk profile possessed by Indonesian athletes. METHODS: This research was a quantitative study using a cross-sectional design, involving 234 Indonesian athletes (163 men and 71 women) from three sports, including football, basketball, and swimming. Data were collected between December 2020 to March 2021 using the Jakarta Cardiovascular Risk Score instrument adapted from the Framingham risk score. Descriptive statistics were utilized to dissect data information for frequency distribution, percentage, mean, and standard deviation. RESULTS: Most of the participants in this study had excessive weekly exercise duration (more than 255 minutes/week) (n=177 athletes, 75.64%). Twenty-one participants (8.97%) had a higher MAP more than normal, and 51 participants (21.79%) had overweight BMI. In addition, 142 participants (60.68%) had a cardiovascular genetic disease from their parents (family history) and most of the participants also were active smokers (n=150, 64.10%). Based on the Jakarta Cardiovascular Risk Score, the Indonesian athletes who participated in this study had a mean cardiovascular risk of -1.5 (SD= 3.088, min-max= (-7) – 6). Most of the participants had low cardiovascular risk (n= 193, 82.48%). However, some participants had moderate and high cardiovascular risk, 32 (13.67%) and 9 (3.85%), respectively. CONCLUSION:  Most of the participants had low cardiovascular risk, however some of the participants had moderate and high cardiovascular risk.

Effect of High-Intensity Interval Training, Moderate Continuous Training, or Guideline-Based Physical Activity on Peak Oxygen Uptake and Myocardial Fibrosis in Patients With Myocardial Infarction: Protocol for a Randomized Controlled Trial

Introduction

High-intensity interval training (HIIT) is an emerging method of cardiac rehabilitation, which is more and more popular in recent years. Research into the effect of HIIT on peak oxygen uptake (VO₂ peak) and myocardial fibrosis among patients with myocardial infarction (MI) is lacking. Here, we describe the rationale along with the protocol for a clinical trial to test the following hypotheses: (1) compared with the control group, VO₂ peak will be increased in both the moderate-intensity continuous training (MICT) and HIIT groups and (2) compared with the control group, myocardial fibrosis due to MI will be improved by HIIT and MICT.

Methods and Analysis

This is a single-center, randomized controlled clinical trial. In total, 180 patients with MI are to be recruited for this study. VO₂ peak will be tested by cardiopulmonary exercise testing (CPET) and myocardial fibrosis will be evaluated by cardiac MR. A variety of blood and psychometric tests and also the peripheral arterial tonometry, reactive hyperemia index for microvascular endothelial function, and microvascular blockage or digital vasomotor response are included.

Ethics and Dissemination

The ethics committee of the Guangdong Provincial People's Hospital has authorized this mechanistic clinical research. Peer-reviewed articles and conference presentations will be used to disseminate the findings.

Trial Registration Number

NCT04863677.

Exercise Training after Myocardial Infarction Attenuates Dysfunctional Ventricular Remodeling and Promotes Cardiac Recovery

Recent evidences have shown that exercise training not only plays a necessary role in maintaining cardiac homeostasis, but also promotes cardiac repair after myocardial infarction. Post-myocardial infarction, exercise training has been observed to effectively increase the maximum cardiac output, and protect myocardial cells against necrosis and apoptosis, thus leading to an improved quality of life of myocardial infarction patients. In fact, exercise training has received more attention as an adjunct therapeutic strategy for both treatment and prevention of myocardial infarction. This review summarizes the experimental evidence of the effects of exercise training in ventricular remodeling after myocardial infarction, and tries to provide theoretical basis along with suitable references for the exercise prescription aimed at prevention and therapy of myocardial infarction.

How Do Master Weightlifters Train? A Transnational Study of Weightlifting Training Practices and Concurrent Training

(1) Background: The wide range of preparedness, physical fitness, and capabilities of older athletes makes it challenging to recommend general training programs for this cohort ranging from ages 35 to 80 and older. Weightlifting has enjoyed an unprecedented growth in recent years, especially among women. The objectives of this study are to describe age and sex differences in self-reported training regimens and concurrent training for Masters weightlifters and investigate regional differences. (2) Methods: A total of 1051 Masters weightlifters from Australia, Canada, Europe, and the USA completed an online survey that included questions on sport history and training practices. (3) Results: A training session typically lasted 1.5 to 2 h for both sexes across all ages. Weightlifters engaged in concurrent training (66.9%), especially in endurance training (24.9%) and CrossFit (36.4%), but the proportions differed across geographic regions. Older females maintained training 4 days per week, while older males reduced this to 3 days per week. (4) Conclusions: Weightlifting training practice of Masters athletes was remarkably consistent across ages, but concurrent training differed between males and females and across regions. This study provides helpful information for athletes, coaches, and sport organizations about the variation in weightlifting training practices and concurrent training of older athletes.

High level physical activity in cardiac rehabilitation: Implications for exercise training and leisure-time pursuits

IMPORTANCE

Regular moderate-to-vigorous physical activity and increased levels of cardiorespiratory fitness (CRF) are widely promoted as cardioprotective measures in secondary prevention interventions.

OBSERVATIONS

A low level of CRF increases the risk of cardiovascular disease (CVD) to a greater extent than merely being physically inactive. An exercise capacity <5 metabolic equivalents (METs), generally corresponding to the bottom 20% of the fitness continuum, indicates a higher mortality group. Accordingly, a key objective in early cardiac rehabilitation (CR) is to increase the intensity of training to >3 METs, to empower patients to vacate this "high risk" group. Moreover, a "good" exercise capacity, expressed as peak METs, identifies individuals with a favorable long-term prognosis, regardless of the underlying extent of coronary disease. On the other hand, vigorous-to-high intensity physical activity, particularly when unaccustomed, and some competitive sports are associated with a greater incidence of acute cardiovascular events. Marathon and triathlon training/competition also have limited applicability and value in CR, are associated with acute cardiac events each year, and do not necessarily provide immunity to the development of or the progression of CVD. Furthermore, extreme endurance exercise regimens are associated with an increased incidence of atrial fibrillation and accelerated coronary artery calcification.

CONCLUSIONS AND RELEVANCE

High-intensity training offers a time-saving alternative to moderate intensity continuous training, as well as other potential advantages. Additional long-term studies assessing safety, adherence, and morbidity and mortality are required before high-intensity CR training can be more widely recommended, especially in previously sedentary patients with known or suspected CVD exercising in non-medically supervised settings.

Dose-response association between moderate to vigorous physical activity and incident morbidity and mortality for individuals with a different cardiovascular health status: A cohort study among 142,493 adults from the Netherlands

BACKGROUND

Moderate to vigorous physical activity (MVPA) is strongly associated with risk reductions of noncommunicable diseases and mortality. Cardiovascular health status may influence the benefits of MVPA. We compare the association between MVPA and incident major adverse cardiovascular events (MACE) and mortality between healthy individuals, individuals with elevated levels of cardiovascular risk factors (CVRF), and cardiovascular disease (CVD).

METHODS AND FINDINGS

A cohort study was performed in the 3 northern provinces of the Netherlands, in which data were collected between 2006 and 2018, with a median follow-up of 6.8 years (Q25 5.7; Q75 7.9). A total of 142,493 participants of the Lifelines Cohort Study were stratified at baseline as (1) healthy; (2) CVRF; or (3) CVD. Individuals were categorized into "inactive" and 4 quartiles of least (Q1) to most (Q4) active based on self-reported MVPA volumes. Primary outcome was a composite of incident MACE and all-cause mortality during follow-up. Cox regression was used to estimate hazard ratios (HRs), 95% confidence intervals (CIs) and P values. The main analyses were stratified on baseline health status and adjusted for age, sex, income, education, alcohol consumption, smoking, protein, fat and carbohydrate intake, kidney function, arrhythmias, hypothyroid, lung disease, osteoarthritis, and rheumatoid arthritis. The event rates were 2.2% in healthy individuals (n = 2,485 of n = 112,018), 7.9% in those with CVRF (n = 2,214 of n = 27,982) and 40.9% in those with CVD (n = 1,019 of n = 2,493). No linear association between MVPA and all-cause mortality or MACE was found for healthy individuals (P = 0.36) and individuals with CVRF (P = 0.86), but a linear association was demonstrated for individuals with CVD (P = 0.04). Adjusted HRs in healthy individuals were 0.81 (95% CI 0.64 to 1.02, P = 0.07), 0.71 (95% CI 0.56 to 0.89, P = 0.004), 0.72 (95% CI 0.57 to 0.91, P = 0.006), and 0.76 (95% CI 0.60 to 0.96, P = 0.02) for MVPA Q1 to Q4, respectively, compared to inactive individuals. In individuals with CVRF, HRs were 0.69 (95% CI 0.57 to 0.82, P < 0.001), 0.66 (95% CI 0.55 to 0.80, P < 0.001), 0.64 (95% CI 0.53 to 0.77, P < 0.001), and 0.69 (95% CI 0.57 to 0.84, P < 0.001) for MVPA Q1 to Q4, respectively, compared to inactive individuals. Finally, HRs for MVPA Q1 to Q4 compared to inactive individuals were 0.80 (95% CI 0.62 to 1.03, P = 0.09), 0.82 (95% CI 0.63 to 1.06, P = 0.13), 0.74 (95% CI 0.57 to 0.95, P = 0.02), and 0.70 (95% CI 0.53 to 0.93, P = 0.01) in CVD patients. Leisure MVPA was associated with the most health benefits, nonleisure MVPA with little health benefits, and occupational MVPA with no health benefits. Study limitations include its observational nature, self-report data about MVPA, and potentially residual confounding despite extensive adjustment for lifestyle risk factors and health-related factors.

CONCLUSIONS

MVPA is beneficial for reducing adverse outcomes, but the shape of the association depends on cardiovascular health status. A curvilinear association was found in healthy and CVRF individuals with a steep risk reduction at low to moderate MVPA volumes and benefits plateauing at high(er) MVPA volumes. CVD patients demonstrated a linear association, suggesting a constant reduction of risk with higher volumes of MVPA. Therefore, individuals with CVDs should be encouraged that "more is better" regarding MVPA. These findings may help to optimize exercise prescription to gain maximal benefits of a physically active lifestyle.

Sudden cardiac death in sports: could we save Pheidippides?

Hereditary diseases under the age of 35 are the most common underlying heart disease, leading to sudden cardiac death (SCD) in competitive sports, while in older people, atherosclerotic coronary artery disease (CAD) is the main cause. The following preventive measures are recommended: (a) The pre-participation cardiovascular screening, (b) the genetic testing, (c) the use of implantable cardioverter-defibrillator (ICD), (d) the prohibition of doping in sports, (e) the prevention of 'exercise-induced' cardiac complications, (f) the reduction of high-risk factors for CAD, and (g) the use of cardiopulmonary resuscitation. The cost-effectiveness of the electrocardiograms in the pre-participation screening programs remains questionable. Genetic testing is recommended in borderline cases and positive family history. Athletes with ICD can, under certain conditions, participate in competitive sports. Excessive endurance exercise appears to harm the endothelium, promotes inflammatory processes and leads to fibrosis in the myocardium, and calcium deposition in the coronary vessels. Cardiac arrest may be reversed if cardiopulmonary resuscitation is performed and a defibrillator is immediately used. Thus, equipping all fields with automatic external defibrillators are recommended.

Exercise Training Duration and Intensity Are Associated With Thicker Carotid Intima-Media Thickness but Improved Arterial Elasticity in Active Children and Adolescents

Even though exercise generally has a positive effect on health, intensive exercise can have adverse effects on the vascular system of adults. This study aimed to investigate the association between training duration and intensity and vascular structure and function in 427 physically active children and adolescents (14.0 ± 1.94 years). In this study, we examined carotid intima-media thickness (cIMT), carotid diameter, and cIMT:diameter-ratio as parameters of carotid arterial structure and arterial compliance (AC), stiffness index β (β), elastic modulus (Ep), and carotid pulse wave velocity (PWVβ) as parameters of carotid arterial function with high-resolution ultrasound. We collected central systolic blood pressure (cSBP) and aortic pulse wave velocity (aPWV) as parameters of central arterial stiffness with an oscillometric device. We used the MoMo Physical Activity Questionnaire to record training duration and intensity. Training duration (p = 0.022) and intensity (p = 0.024) were associated with higher cIMT. Further, training duration was associated with lower central arterial stiffness (cSBP: p = 0.001; aPWV: p = 0.033) and improved AC (p < 0.001). Higher training intensity was related to improved AC (p < 0.001) and larger carotid diameter (p = 0.040). Boys presented thicker cIMT (p = 0.010), improved AC (p = 0.006), and lower central arterial stiffness (cSBP: p < 0.001; aPWV: p = 0.016) associated with higher training duration. Girls presented improved AC (p = 0.023) and lower Ep (p = 0.038) but higher β (p = 0.036) associated with higher training duration. Only boys demonstrated thicker cIMT (p = 0.016) and improved AC (p = 0.002) associated with higher training intensity. A quintile analyses of the training duration revealed thicker cIMT of children and adolescents in Q1 and Q5 than that in Q4 and Q5. Besides, Q1 showed lower cSBP compared to Q4 and Q5. Regarding training intensity, Q5 had thicker cIMT than Q2 and Q3. Although a higher training load is associated with thicker cIMT, the common carotid artery is also more elastic. This suggests that a higher training load leads to a functional adaptation of the carotid artery in youth.

Sleep and physical activity in relation to all-cause, cardiovascular disease and cancer mortality risk

OBJECTIVES

Although both physical inactivity and poor sleep are deleteriously associated with mortality, the joint effects of these two behaviours remain unknown. This study aimed to investigate the joint association of physical activity (PA) and sleep with all-cause and cause-specific mortality risks.

METHODS

380 055 participants aged 55.9 (8.1) years (55% women) from the UK Biobank were included. Baseline PA levels were categorised as high, medium, low and no moderate-to-vigorous PA (MVPA) based on current public health guidelines. We categorised sleep into healthy, intermediate and poor with an established composited sleep score of chronotype, sleep duration, insomnia, snoring and daytime sleepiness. We derived 12 PA-sleep combinations, accordingly. Mortality risks were ascertained to May 2020 for all-cause, total cardiovascular disease (CVD), CVD subtypes (coronary heart disease, haemorrhagic stroke, ischaemic stroke), as well as total cancer and lung cancer.

RESULTS

After an average follow-up of 11.1 years, sleep scores showed dose-response associations with all-cause, total CVD and ischaemic stroke mortality. Compared with high PA-healthy sleep group (reference), the no MVPA-poor sleep group had the highest mortality risks for all-cause (HR (95% CIs), (1.57 (1.35 to 1.82)), total CVD (1.67 (1.27 to 2.19)), total cancer (1.45 (1.18 to 1.77)) and lung cancer (1.91 (1.30 to 2.81))). The deleterious associations of poor sleep with all outcomes, except for stroke, was amplified with lower PA.

CONCLUSION

The detrimental associations of poor sleep with all-cause and cause-specific mortality risks are exacerbated by low PA, suggesting likely synergistic effects. Our study supports the need to target both behaviours in research and clinical practice.

Cardiac Biomarkers and Autoantibodies in Endurance Athletes: Potential Similarities with Arrhythmogenic Cardiomyopathy Pathogenic Mechanisms

The “Extreme Exercise Hypothesis” states that when individuals perform training beyond the ideal exercise dose, a decline in the beneficial effects of physical activity occurs. This is due to significant changes in myocardial structure and function, such as hemodynamic alterations, cardiac chamber enlargement and hypertrophy, myocardial inflammation, oxidative stress, fibrosis, and conduction changes. In addition, an increased amount of circulating biomarkers of exercise-induced damage has been reported. Although these changes are often reversible, long-lasting cardiac damage may develop after years of intense physical exercise. Since several features of the athlete’s heart overlap with arrhythmogenic cardiomyopathy (ACM), the syndrome of “exercise-induced ACM” has been postulated. Thus, the distinction between ACM and the athlete’s heart may be challenging. Recently, an autoimmune mechanism has been discovered in ACM patients linked to their characteristic junctional impairment. Since cardiac junctions are similarly impaired by intense physical activity due to the strong myocardial stretching, we propose in the present work the novel hypothesis of an autoimmune response in endurance athletes. This investigation may deepen the knowledge about the pathological remodeling and relative activated mechanisms induced by intense endurance exercise, potentially improving the early recognition of whom is actually at risk.

Excessive exercise training causes mitochondrial functional impairment and decreases glucose tolerance in healthy volunteers

Exercise training positively affects metabolic health through increased mitochondrial oxidative capacity and improved glucose regulation and is the first line of treatment in several metabolic diseases. However, the upper limit of the amount of exercise associated with beneficial therapeutic effects has not been clearly identified. Here, we used a training model with a progressively increasing exercise load during an intervention over 4 weeks. We closely followed changes in glucose tolerance, mitochondrial function and dynamics, physical exercise capacity, and whole-body metabolism. Following the week with the highest exercise load, we found a striking reduction in intrinsic mitochondrial function that coincided with a disturbance in glucose tolerance and insulin secretion. We also assessed continuous blood glucose profiles in world-class endurance athletes and found that they had impaired glucose control compared with a matched control group.

Occupational lifting and risk of hypertension, stratified by use of anti-hypertensives and age - a cross-sectional and prospective cohort study

Background

Heavy occupational lifting is prevalent in the general working population and is sparsely reported to associate with hypertension, especially among older and hypertensive workers. We investigated if heavy occupational lifting is associated with hypertension and blood pressure (BP) in both cross-sectional and prospective study designs in the Copenhagen General Population Study, stratified by age, and use of anti-hypertensives.

Methods

Participation was conducted following the declaration of Helsinki and approved by the ethical committee (H-KF-01-144/01). By multivariable logistic and linear regression models, we investigated the association between heavy occupational lifting and hypertension, in a cross-sectional design (n = 67,363), using anti-hypertensives or BP ≥140/≥90 mmHg as outcome, and in a prospective design (n = 7020) with an above-median change in systolic BP (SBP) from baseline to follow-up and/or a shift from no use to use of anti-hypertensives as outcome, with and without stratification by age and use of anti-hypertensives.

Results

The odds ratio for hypertension was estimated at 0.97 (99% CI: 0.93–1.00) in the cross-sectional analysis, and at 1.08 (99% CI: 0.98–1.19) in the prospective analysis. The difference in SBP among workers with versus without heavy occupational lifting was estimated at − 0.29 mmHg (99% CI -0.82 – 0.25) in the cross-sectional and at 1.02 mmHg (99% CI -0.41 – 2.45) in the prospective analysis. No significant interaction between heavy occupational lifting and age, nor use of anti-hypertensives were shown.

Conclusions

Only the prospective analysis indicated heavy occupational lifting to increase the risk of hypertension. Further research on the association between occupational lifting and hypertension are needed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-10651-w.

Effects of short duration high intensity competition on cardiac and cell damage biomarkers

The purpose of this study was to investigate the cardiac biomarkers like cardiac troponin T (cTnT), cardiac troponin I, and creatine kinase-MB (CK-MB) and the cell damage biomarkers including creatine phosphokinase (CPK), C-reactive protein (CRP), lactate dehydrogenase (LDH), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) in response to a short-duration high-intensity competition with correction of the post-exercise raw data with the plasma volume loss in trained athletes. Thirty-two male athletes (age, 26.9±4.7 years) competed in 8 min high-intensity competition. The competition items included: running for 400 meters; three-stage deadlifting; bar pulling up; and 30 kg kettlebell swinging. Venous blood samples were obtained before and immediately after the competition and biomarkers analysed. Plasma volume changes were estimated from haemoglobin and haematocrit readings before and after the competition. A significant increase was shown immediately after the competition compared to resting in cTnT, AST, ALT, CPK, and CRP (P<0/001). CK-MB showed no significant difference. When raw data were corrected for plasma volume loss, CPK showed a significant increase (P<0.001), and LDH and CK-MB a significant decrease (P<0.001), however cTnT, AST, ALT and CRP showed no significant difference. The plasma volume loss can affect the response of cardiac and cellular damage biomarkers to exercise. High-intensity competition for 8 min did not elevate the cardiac biomarkers, but elevated the muscle biomarkers.

Effects of medium- and long-distance running on cardiac damage markers in amateur runners: a systematic review, meta-analysis, and metaregression

BACKGROUND

To finish an endurance race, athletes perform a vigorous effort that induces the release of cardiac damage markers. There are several factors that can affect the total number of these markers, so the aim of this review was to analyze the effect of endurance running races on cardiac damage markers and to identify the factors that modify the levels of segregation of these cardiac damage markers.

METHODS

A systematic search of PubMed, Web of Science, and the Cochrane Library databases was performed. This analysis included studies where the acute effects of running races on cardiac damage markers (troponin I and troponin T) were analyzed, assessing the levels of these markers before and after the races.

RESULTS

The effects of running races on troponin I (mean difference = 0.0381 ng/mL) and troponin T (mean difference = 0.0256 ng/mL) levels were significant. The ages (R2 = 14.4%, p = 0.033) and body mass indexes (R2 = 14.5%, p = 0.045) of the athletes had a significant interaction with troponin I. In addition, gender, mean speed, time to finish the race, and type of race can affect the level of cardiac damage markers.

CONCLUSION

Endurance running races induce the release of cardiac-damage markers that remain elevated for at least 24 h after the races. In addition, young male athletes with high body mass indexes who perform races combining long duration and moderate intensity (i.e., marathons) release the highest levels of cardiac damage markers. Physicians should take into consideration these results in the diagnosis and treatment of patients admitted to the hospital days after finishing endurance running races.

The Endothelium as a Therapeutic Target in Diabetes: A Narrative Review and Perspective

Diabetes has reached worldwide epidemic proportions, and threatens to be a significant economic burden to both patients and healthcare systems, and an important driver of cardiovascular mortality and morbidity. Improvement in lifestyle interventions (which includes increase in physical activity via exercise) can reduce diabetes and cardiovascular disease mortality and morbidity. Encouraging a population to increase physical activity and exercise is not a simple feat particularly in individuals with co-morbidities (obesity, heart disease, stroke, peripheral vascular disease, and those with cognitive and physical limitations). Translation of the physiological benefits of exercise within that vulnerable population would be an important step for improving physical activity goals and a stopgap measure to exercise. In large part many of the beneficial effects of exercise are due to the introduction of pulsatile shear stress (PSS) to the vascular endothelium. PSS is a well-known stimulus for endothelial homeostasis, and induction of a myriad of pathways which include vasoreactivity, paracrine/endocrine function, fibrinolysis, inflammation, barrier function, and vessel growth and formation. The endothelial cell mediates the balance between vasoconstriction and relaxation via the major vasodilator endothelial derived nitric oxide (eNO). eNO is critical for vasorelaxation, increasing blood flow, and an important signaling molecule that downregulates the inflammatory cascade. A salient feature of diabetes, is endothelial dysfunction which is characterized by a reduction of the bioavailability of vasodilators, particularly nitric oxide (NO). Cellular derangements in diabetes are also related to dysregulation in Ca²⁺ handling with increased intracellular Ca²⁺overload, and oxidative stress. PSS increases eNO bioavailability, reduces inflammatory phenotype, decreases intracellular Ca²⁺ overload, and increases antioxidant capacity. This narrative review and perspective will outline four methods to non-invasively increase PSS; Exercise (the prototype for increasing PSS), Enhanced External Counterpulsation (EECP), Whole Body Vibration (WBV), Passive Simulated Jogging and its predicate device Whole Body Periodic Acceleration, and will discuss current knowledge on their use in diabetes.

Ten-year follow-up of cardiac function and neural regulation in a group of amateur half-marathon runners

OBJECTIVE

In the last years, a debate exists about type, intensity and frequency of physical exercise that is really indicated to protect healthy subjects from cardiovascular disease. Regular physical training has been associated with an improved cardiovascular risk profile, but it has also been demonstrated that strenuous and uncontrolled physical exercise could be dangerous, in terms of increased cardiovascular morbidity and mortality. In the present study, we evaluated a group of 35 amateur half-marathon runners, who were likewise studied 10 years before (B). The results of B suggested that an increased cardiac sympathetic modulation could potentially represent a negative prognostic factor. The aim of this follow-up was to assess the medium-long-term effects of moderate to vigorous physical training on the cardiovascular neural control, cardiac function and occurrence of cardiovascular diseases.

METHODS

Each enrolled subject underwent: (1) an interview and physical examination to ascertain the presence of cardiovascular disease; (2) standing test to evaluate the cardiovascular neural control by means of heart rate variability (HRV), arterial blood pressure (AP) variability and baroreflex sensitivity (BRS); (3) transthoracic echocardiography to evaluate cardiac function.

RESULTS

At 10-year follow-up (FU), in this group of middle-aged athletes the occurrence of cardiovascular diseases was low, not unlike that of the overall population. The results of HRV analysis showed a decreased sympathetic and increased vagal modulation directed to the heart, compared with B. In addition, HRV, AP variability and BRS indices showed a physiological response to active standing. Finally, athletes had normal echocardiographic measures.

CONCLUSION

We conclude that in our group of athletes a regular moderate-vigorous physical training through the 10 years was quite beneficial as the prevalence of sympathetic cardiac modulation observed at B was not accompanied by increased cardiovascular risk, on the contrary a slight prevalence of vagal indices was observed at FU.

Intense Endurance Exercise: A Potential Risk Factor in the Development of Heart Disease

Exercise is known to improve cardiac health; however, the upper limit of exercise is not as clear. High-intensity endurance exercise and its association with cardiac dysfunction are becoming more important as more people in the USA participate in endurance activity. Intensive endurance exercise is associated with heart disease. Peer-reviewed primary literature related to endurance exercise, cardiac remodelling, myocardial fibrosis, and arrhythmia was searched and selected from the PubMed Database to be reviewed. Increased cardiac remodelling, myocardial fibrosis, and arrhythmias were associated with increased endurance exercise in most instances. Clinically significant dysfunction from endurance exercise-induced cardiac remodelling and myocardial fibrosis is not certain. However, increased incidence of sinus node disease (SND) and atrial flutter in endurance athletes, even after deconditioning, seems to be most associated with endurance exercise. Cardiac remodelling, fibrosis, and arrhythmia were associated with cardiac dysfunction. All review articles in this study were limited by a low sample size since it was difficult to obtain a full record of previous endurance activity. The reversibility of cardiac changes needs to be further investigated and can be applied in the differential diagnosis of other cardiomyopathies. The interaction between performance-enhancing drugs and endurance exercise needs to be further studied to determine its action on cardiac health. Findings from these studies could contribute to exercise recommendations.

Re-evaluating the causes and consequences of non-resolving inflammation in chronic cardiovascular disease

Cardiac injuries, like heart attacks, drive the secondary pathology with advanced heart failure. In this process, non-resolving inflammation is a prime component of accelerated cardiovascular disease and subsequent fatal events associated with imbalanced diet, physical inactivity, disrupted circadian rhythms, neuro-hormonal stress, and poly- or co-medication. Laboratory rodents have established that splenic leukocyte-directed resolution mechanisms are essential for cardiac repair after injury. Here, we discuss the impact of three lifestyle-related factors that are prime causes of derailed cardiac healing, putative non-resolving inflammation-resolution mechanisms in cardiovascular diseases, and progressive heart failure after cardiac injury. The presented review resurfaces the lifestyle-related risks and future research directions required to understand the molecular and cellular mechanisms between the causes of cardiovascular disease and their related consequences of non-resolving inflammation.

Exercise-Related Acute Cardiovascular Events and Potential Deleterious Adaptations Following Long-Term Exercise Training: Placing the Risks Into Perspective-An Update: A Scientific Statement From the American Heart Association

Epidemiological and biological plausibility studies support a cause-and-effect relationship between increased levels of physical activity or cardiorespiratory fitness and reduced coronary heart disease events. These data, plus the well-documented anti-aging effects of exercise, have likely contributed to the escalating numbers of adults who have embraced the notion that "more exercise is better." As a result, worldwide participation in endurance training, competitive long distance endurance events, and high-intensity interval training has increased markedly since the previous American Heart Association statement on exercise risk. On the other hand, vigorous physical activity, particularly when performed by unfit individuals, can acutely increase the risk of sudden cardiac death and acute myocardial infarction in susceptible people. Recent studies have also shown that large exercise volumes and vigorous intensities are both associated with potential cardiac maladaptations, including accelerated coronary artery calcification, exercise-induced cardiac biomarker release, myocardial fibrosis, and atrial fibrillation. The relationship between these maladaptive responses and physical activity often forms a U- or reverse J-shaped dose-response curve. This scientific statement discusses the cardiovascular and health implications for moderate to vigorous physical activity, as well as high-volume, high-intensity exercise regimens, based on current understanding of the associated risks and benefits. The goal is to provide healthcare professionals with updated information to advise patients on appropriate preparticipation screening and the benefits and risks of physical activity or physical exertion in varied environments and during competitive events.