Athletic Remodeling in Female College Athletes: The "Morganroth Hypothesis" Revisited

Investigation of left atrial mechanical function and left ventricular systolic and diastolic parameters in athletes performing resistance exercise and combined exercise

Some individuals who go to fitness centers for various purposes perform resistance exercise (RE) alone, while others engage in combined exercise (CE) by including cardio exercises along with RE. Studying the effects of these two different training methods on left ventricular (LV) systolic and diastolic parameters and left atrial mechanical function is an important step toward understanding the effects of different types of exercise on cardiac function. This knowledge has significant implications for public health, as it can inform the development of targeted and effective exercise programs that prioritize cardiovascular health and reduce the risk of adverse outcomes. Therefore, the primary aim of this study is to comprehensively investigate the LV systolic and diastolic parameters of athletes who engage in RE and CE using ECHO, to contribute to the growing body of literature on the cardiovascular effects of different types of exercise. Forty-two amateur athletes aged between 17 and 52 were included in our study. The participants consisted of the RE (n = 26) group who did only resistance exercise during the weekly exercise period, and the CE group (n = 16) who also did cardio exercise with resistance exercises. After determining sports age (year), weekly exercise frequency (day), and training volume (min) in addition to demographic information of RE and CE groups, left ventricular systolic and diastolic parameters and left atrial functions were determined by ECHO. Findings from our study revealed that parameters including the left ventricular end-diastolic diameter (LVEDD) (p = .008), left ventricular end-diastolic volume (LVEDV) (p = .020), stroke volume index (SV-I) (p = .048), conduit volume (CV-I) (p = .001), and aortic strain (AS) (p = .017) were notably higher in the RE group compared to the CE group. Also left atrial active emptying volüme (LAAEV) of CE was higher than the RE group (p = .031). In conclusion, the cardiac parameters of the RE group showed more athlete's heart characteristics than the CE group. These results may help to optimize the cardiovascular benefits of exercise routines while minimizing the potential risks associated with improper training.

The athlete's heart: allometric considerations on published papers and relation to cardiovascular variables

To evaluate the morphology of the "athlete's heart", left ventricular (LV) wall thickness (WT) and end-diastolic internal diameter (LVIDd) at rest were addressed in publications on skiers, rowers, swimmers, cyclists, runners, weightlifters (n = 927), and untrained controls (n = 173) and related to the acute and maximal cardiovascular response to their respective disciplines. Dimensions of the heart at rest and functional variables established during the various sport disciplines were scaled to body weight for comparison among athletes independent of body mass. The two measures of LV were related (r = 0.8; P = 0.04) across athletic disciplines. With allometric scaling to body weight, LVIDd was similar between weightlifters and controls but 7%-15% larger in the other athletic groups, while WT was 9%-24% enlarged in all athletes. The LVIDd was related to stroke volume, oxygen pulse, maximal oxygen uptake, cardiac output, and blood volume (r =  ~ 0.9, P < 0.05), while there was no relationship between WT and these variables (P > 0.05). In conclusion, while cardiac enlargement is, in part, essential for the generation of the cardiac output and thus stroke volume needed for competitive endurance exercise, an enlarged WT seems important for the development of the wall tension required for establishing normal arterial pressure in the enlarged LVIDd.

Left Ventricular, Left Atrial and Right Ventricular Strain Modifications after Maximal Exercise in Elite Ski-Mountaineering Athletes: A Feasibility Speckle Tracking Study

Eleven world elite ski-mountaineering (Ski-Mo) athletes were evaluated for pronounced echocardiographic physiological remodeling as the primary aim of our feasibility speckle tracking study. In this context, sports-related cardiac remodeling was analyzed by performing two-dimensional echocardiography, including speckle tracking analysis of the left atrium (LA), right ventricle (RV) and left ventricular (LV) global longitudinal strain (LV-GLS) at rest and post-peak performance. The feasibility echocardiographic speckle tracking analysis was performed on eleven elite Ski-Mo athletes, which were obtained in 2022 during the annual medical examination. The obtained data of the professional Ski-Mo athletes (11 athletes, age: 18-26 years) were compared for different echocardiographic parameters at rest and post-exercise. Significant differences were found for LV-GLS mean (p = 0.0036) and phasic LA conduit strain pattern at rest and post-exercise (p = 0.0033). Furthermore, negative correlation between LV mass and LV-GLS (p = 0.0195, r = -0.69) and LV mass Index and LV-GLS (p = 0.0253, r = -0.66) at rest were elucidated. This descriptive reporting provided, for the first time, a sport-specific dynamic remodeling of an entire elite national team of the Ski-Mo athlete's left heart and elucidated differences in the dynamic deformation pattern of the left heart.

The Athlete's Heart-Challenges and Controversies: JACC Focus Seminar 4/4

Regular exercise promotes structural, functional, and electrical remodeling of the heart, often referred to as the "athlete's heart," with intense endurance sports being associated with the greatest degree of cardiac remodeling. However, the extremes of exercise-induced cardiac remodeling are potentially associated with uncommon side effects. Atrial fibrillation is more common among endurance athletes and there is speculation that other arrhythmias may also be more prevalent. It is yet to be determined whether this arrhythmic susceptibility is a result of extreme exercise remodeling, genetic predisposition, or other factors. Gender may have the greatest influence on the cardiac response to exercise, but there has been far too little research directed at understanding differences in the sportsman's vs sportswoman's heart. Here in part 4 of a 4-part seminar series, the controversies and ambiguities regarding the athlete's heart, and in particular, its arrhythmic predisposition, genetic, and gender influences are reviewed in depth.

Cardiac Remodeling in Elite Aquatic Sport Athletes

OBJECTIVE

To characterize and compare the sport-specific cardiac structure of elite swimmers (SW), water polo players (WP), and artistic swimmers (AS).

DESIGN

A cross-sectional assessment of elite aquatic athletes' hearts.

SETTING

The athletes' village at the 2019 FINA World Championships.

PARTICIPANTS

Ninety athletes from swimming (SW) (20 M/17 F), water polo (WP) (21 M/9 F), and artistic swimming (AS) (23 F).

ASSESSMENT AND MAIN OUTCOME MEASURES

An echocardiographic assessment of cardiac structure was performed on noncompetition days.

RESULTS

Male SW displayed primarily eccentric volume-driven remodeling, whereas male WP had a greater incidence of pressure-driven concentric geometry (SW = 5%, WP = 25%) with elevated relative wall-thickness (RWT) (SW = 0.35 ± 0.04, WP = 0.44 ± 0.08, P < 0.001). Female SW and WP hearts were similar with primarily eccentric-remodeling, but SW and WP had greater concentricity index than artistic swimmers (SW = 6.74 ± 1.45 g/(mL)2/3, WP = 6.80 ± 1.24 g/(mL)2/3, AS = 5.52 ± 1.08 g/(mL)2/3, P = 0.007). AS had normal geometry, but with increased posterior-wall specific RWT (SW = 0.32 ± 0.05, AS = 0.42 ± 0.11, P = 0.004) and greater left atrial area than SW (SW = 9.7 ± 0.9 cm2/m2, AS = 11.0 ± 1.1 cm2/m2, P = 0.003). All females had greater incidence of left ventricular (LV) posterior/septal wall-thickness ≥11 mm than typically reported (SW = 24%, WP = 11%, AS = 17%).

CONCLUSIONS

Male athletes presented classic sport-specific differentiation, with SW demonstrating primarily volume-driven eccentric remodelling, and WP with greater concentric geometry indicative of pressure-driven remodeling. Female SW and WP did not display this divergence, likely because of sex-differences in adaptation. AS had unique LV-specific adaptations suggesting elevated pressure under low-volume conditions. The overall incidence of elevated wall-thickness in female athletes may point to an aquatic specific pressure-stress.

Sex Matters: A Comprehensive Comparison of Female and Male Hearts

Cardiovascular disease in women remains under-diagnosed and under-treated. Recent studies suggest that this is caused, at least in part, by the lack of sex-specific diagnostic criteria. While it is widely recognized that the female heart is smaller than the male heart, it has long been ignored that it also has a different microstructural architecture. This has severe implications on a multitude of cardiac parameters. Here, we systematically review and compare geometric, functional, and structural parameters of female and male hearts, both in the healthy population and in athletes. Our study finds that, compared to the male heart, the female heart has a larger ejection fraction and beats at a faster rate but generates a smaller cardiac output. It has a lower blood pressure but produces universally larger contractile strains. Critically, allometric scaling, e.g., by lean body mass, reduces but does not completely eliminate the sex differences between female and male hearts. Our results suggest that the sex differences in cardiac form and function are too complex to be ignored: the female heart is not just a small version of the male heart. When using similar diagnostic criteria for female and male hearts, cardiac disease in women is frequently overlooked by routine exams, and it is diagnosed later and with more severe symptoms than in men. Clearly, there is an urgent need to better understand the female heart and design sex-specific diagnostic criteria that will allow us to diagnose cardiac disease in women equally as early, robustly, and reliably as in men.

Systematic Review Registration

https://livingmatter.stanford.edu/.

Cardiac structure and function in elite female athletes: A systematic review and meta-analysis

We conducted a meta-analysis to synthesize the best available evidence comparing cardiac biventricular structure and function using cardiac magnetic resonance imaging (CMR) and transthoracic echocardiography (TTE) in elite female athletes and healthy controls (HC). Chronic exposure to exercise may induce cardiac chamber enlargement as a means to augment stroke volume, a condition known as the "athlete's heart." These changes have not been clearly characterized in female athletes. Multiple databases were searched from inception to June 18, 2019. Outcomes of interest included left ventricular (LV) and right ventricular (RV) dimensional, volumetric, mass, and functional assessments in female athletes. Most values were indexed to body surface area. The final search yielded 22 studies, including 1000 female athletes from endurance, strength, and mixed athletic disciplines. CMR-derived LV end-diastolic volume (LVEDV) and RV end-diastolic volume (RVEDV) were greater in endurance athletes (EA) versus HC (17.0% and 18.5%, respectively; both p < 0.001). Similarly, TTE-derived LVEDV and RVEDV were greater in EA versus HC (16.8% and 28.0%, respectively; both p < 0.001). Both LVEF and RVEF were lower in EA versus HC, with the most pronounced difference observed in RVEF via TTE (9%) (p < 0.001). LV stroke volume was greater in EA versus HC via both CMR (18.5%) and TTE (13.2%) (both p < 0.05). Few studies reported data for the mixed athlete (MA) population and even fewer studies reported data for strength athletes (SA), therefore a limited analysis was performed on MA and no analysis was performed on SA. This evidence-synthesis review demonstrates the RV may be more susceptible to ventricular enlargement. General changes in LV and RV structure and function in female EA mirrored changes observed in male counterparts. Further studies are needed to determine if potential adverse outcomes occur secondary to these changes.

Right heart exercise-training-adaptation and remodelling in endurance athletes

Long-term sports training leads to myocardial adaptations, with remodelling of the heart chambers. However, while myocardial adaptations of the left heart are well described, remodelling of the right heart and its impact on the development of arrhythmias is still debated. To conduct a systematic review on right ventricle (RV) and right atrium (RA) structural and functional changes in athletes who participate in long-term endurance training. Systematic review. A systematic literature search was conducted. All the articles reporting right heart echocardiographic (ECHO) and cardiac magnetic resonance (CMR) parameters evaluated in endurance athletes and sedentary subjects were considered eligible. A multivariate analysis was conducted to investigate whether age, sex, body surface area (BSA), intensity of training are associated with RV ECHO, CMR parameters and RA ECHO parameters. A positive association between age and right atrium area (RAA) (P = 0.01) was found. This is a negative association to RV E/A (P = 0.004), and RV end diastolic diameter (RVED) longitudinal (P = 0.01). A positive association between BSA and RVED middle (P = 0.001), as well between BSA and RAA (P = 0.05) was found, along with a negative association with RV E/A (P = 0.002). A positive association between intensity of training and RV end systolic area (RVESA) (P = 0.03), RV end diastolic volume indexed (RVEDVI) (P = 0.01), RV end systolic volume indexed (RVESVI) (P = 0.01) was found, along with a negative association with ejection fraction (EF %) (P = 0.01). Endurance athletes demonstrated an association between RV remodelling and age, BSA and intensity of training.

Differences in Left Ventricular Function at Rest and during Isometric Handgrip Exercise in Elite Aquatic Sport Athletes

PURPOSE

Elite swimmers (Sw) have lower diastolic function compared to elite runners, possibly as an adaptation to the aquatic training environment. Water polo players (WP) and artistic swimmers (AS) are exposed to the same hydrostatic pressures as Sw, but are subject to different training intensities, postures, and hemodynamic stressors. Our purpose was to compare resting and exercising cardiac function in elite Sw, WP, and AS, to characterize the influence of training for aquatic-sport on left ventricular (LV) adaptation.

METHODS

Ninety athletes (Sw:20 M/17F; WP:21 M/9F; AS:23F) at the 2019 FINA World Championships volunteered for resting and stress (3 min 30% maximal isometric handgrip) echocardiographic assessment of LV global function and mechanics.

RESULTS

Male Sw displayed greater resting systolic and diastolic function compared to WP; however, both groups maintained stroke volume under high-pressure handgrip stress (Sw:[INCREMENT]-4 ± 12%; WP:[INCREMENT]-1 ± 13%, P = 0.11). There were no differences between female Sw and WP resting LV function, but Sw demonstrated greater function over AS. During isometric handgrip, all female sport athletes maintained stroke volume (Sw:[INCREMENT]3 ± 16%; WP:[INCREMENT]-10 ± 11%; AS:[INCREMENT]-2 ± 14%, P = 0.46), but WP had improved apical rotation ([INCREMENT]1.7 ± 4.5°), which was reduced in AS ([INCREMENT]-3.1 ± 4.5°) and maintained in Sw ([INCREMENT]-0.5 ± 3.8°, P = 0.04). Unlike Sw and WP, AS displayed a unique maintenance of early filling velocity during handgrip exercise (Sw:[INCREMENT]-3.5 ± 14.7 cm/s; WP:[INCREMENT]-15.1 ± 10.8 cm/s; AS:[INCREMENT]1.5 ± 15.3 cm/s, P = 0.02).

CONCLUSION

Among male athletes, Sw display primarily volume-based functional adaptations distinct from the mixed volume-pressure adaptations of WP; however, both groups can maintain stroke volume with increased afterload. Female Sw and WP do not demonstrate sport-specific differences like males, perhaps owing to sex-differences in adaptation, but have greater volume-based adaptations than AS. Lastly, AS display unique functional adaptations, that may be driven by elevated pressures under low-volume conditions.

Relationship between echocardiogram and physical parameters in experienced resistance trainers: a pilot study

BACKGROUND

A paucity of research exists concerning physiological factors influencing heart structure and function in strength athletes. This pilot study investigated whether body composition and muscle performance are associated with indices of cardiac structure and function in experienced resistance trainers.

METHODS

A cross-sectional study designed was employed to address the study aim. Seventeen males (median age 33.0 years) and eight females (median age 32.5 years) with backgrounds in bodybuilding and powerlifting participated in this study. Muscle performance, body composition and echocardiographic measures were performed. Mann-Whitney U-tests were used to examine differences between males and females. Spearman's Rho partial correlation analyses (adjusting for sex) were conducted to examine relationships between physical and echocardiogram parameters.

RESULTS

Moderate to strong positive correlations were found between fat-free mass and aortic root, right ventricular internal dimension, interventricular septum thickness, left ventricular posterior wall thickness, left atrium area, left ventricular end-diastolic volume, and left ventricular end-systolic volume (r: 0.43-0.76, P≤0.03). Moderate to strong positive correlations were found between leg press 1RM and aortic root, left ventricular internal dimension diastole, left atrium area, left ventricular end-diastolic volume, and left ventricular end-systolic volume (r: 0.49-0.67, P≤0.02).

CONCLUSIONS

Resistance trainers with greater fat-free mass and lower body strength appear to have larger cardiac structures. Changes in heart size and function are likely to result from long-term strenuous resistance training. Due to the suspected prevalence of performance enhancing drug use among powerlifters and bodybuilders, care is required to rule out pathological conditions.

Stimulus-specific functional remodeling of the left ventricle in endurance and resistance-trained men

Left ventricular (LV) structural remodeling following athletic training has been evidenced through training-specific changes in wall thickness and geometry. Whether the LV response to changes in hemodynamic load also adapts in a training-specific manner is unknown. Using echocardiography, we examined LV responses of endurance-trained (n = 15), resistance-trained (n = 14), and nonathletic men (n = 13) to 1) 20, 40, and 60% one repetition-maximum (1RM), leg-press exercise and 2) intravascular Gelofusine infusion (7 mL/kg) with passive leg raise. While resting heart rate was lower in endurance-trained participants versus controls (P = 0.001), blood pressure was similar between groups. Endurance-trained individuals had lower wall thickness but greater LV mass relative to body surface area versus controls, with no difference between resistance-trained individuals and controls. Leg press evoked a similar increase in blood pressure; however, resistance-trained participants preserved stroke volume (SV; -3 ± 8%) versus controls at 60% 1RM (-15 ± 7%, P = 0.001). While the maintenance of SV was related to the change in longitudinal strain across all groups (R = 0.537; P = 0.007), time-to-peak strain was maintained in resistance-trained but delayed in endurance-trained individuals (1 vs. 12% delay; P = 0.021). Volume infusion caused a similar increase in end-diastolic volume (EDV) and SV across groups, but leg raise further increased EDV only in endurance-trained individuals (5 ± 5 to 8 ± 5%; P = 0.018). Correlation analysis revealed a relationship between SV and longitudinal strain following infusion and leg raise (R = 0.334, P = 0.054); however, we observed no between-group differences in longitudinal myocardial mechanics. In conclusion, resistance-trained individuals better maintained SV during pressure loading, whereas endurance-trained individuals demonstrated greater EDV reserve during volume loading. These data provide novel evidence of training-specific LV functional remodeling.NEW & NOTEWORTHY Training-specific functional remodeling of the LV in response to different loading conditions has been recently suggested, but not experimentally tested in the same group of individuals. Our data provide novel evidence of a dichotomous, training-specific LV adaptive response to hemodynamic pressure or volume loading.

Changes in Body Composition and Its Relationship to Performance in Elite Female Track and Field Athletes Transitioning to the Senior Division

Many elite female athletes struggle to maintain performance while transitioning from high school to university-level (senior) sports. This study explores factors of body composition that influenced performance in elite junior female track and field athletes transitioning to the senior division. Forty-two elite female track and field athletes, ranked among the top 100 in Japan, were enrolled in this study. Whole-body mode dual-energy X-ray absorptiometry scans were performed during the post-season of 2016 and 2017. Athletes’ performances were assessed using the International Association of Athletics Federation scoring system. Relationships between changes in performance and those in body composition were investigated. There were significant negative correlations between changes in performance and fat mass (FM), and percentage FM (FM%). This was seen in total body and lower extremities, and not in the trunk and upper extremities. In addition, there was a positive correlation between changes in performance and percentage lean mass (LM%). However, there were no correlations between changes in performance and LM and total mass. Elite female track and field athletes transitioning to senior division should decrease their FM and FM% and increase LM%, to sustain or improve performance. It is also more important to monitor changes in body composition than body mass.

Scaling left ventricular mass in adolescent female soccer players

BACKGROUND

The aim of the study was to examine the contribution of chronological age (CA), skeletal maturation, training experience and concurrent body size descriptors, to inter-individual variance in left ventricular mass (LVM) among female adolescent soccer players.

METHODS

The sample included 228 female soccer players 11.8-17.1 years. Training experience defined as years of participation in competitive soccer (range 2-9 years), was obtained by interview. Stature, body mass and skinfolds (triceps, medial calf) were measured. Fat mass was estimated; Fat-free mass was derived. LVM was assessed by echocardiography. Skeletal maturity status was as the difference of skeletal age (SA, Fels method) minus CA.

RESULTS

Fat-free mass was the most prominent single predictor of LVM (R2 = 36.6%). It was associated with an allometric coefficient close to linearity (k = 0.924, 95%CI: 0.737 to 1.112). A significant multiplicative allometric model including body mass, fat-free mass, CA, training experience and skeletal maturity status was also obtained (R = 0.684; R2 = 46.2%).

CONCLUSION

Stature has limitations as a valid size descriptor of LVM. Body mass, fat-free mass, training experience, CA, body mass and skeletal maturity status were relevant factors contributing to inter-individual variability in LVM.

The impact of demographic, anthropometric and athletic characteristics on left atrial size in athletes

The structural adaptations of the “athlete's heart” include left atrial (LA) enlargement. A literature search was performed based on PubMed listings up to November 2, 2019 using “athletes AND left atrium,” “athletes AND LA,” “sports AND left atrium,” “sports AND LA,” “exercise AND left atrium,” and “exercise AND LA” as the search terms. Eligible studies included those reporting the influence of demographic, anthropometric and athletic characteristics on LA size in athletes. A total of 58 studies were included in this review article. Although LA volume has been reported to be greater in males compared to females when indexed for body surface area (BSA), there was no difference between sexes. The positive association between LA size and age in athletes may reflect the increase in body size with maturation in nonadult athletes and the training age of endurance athletic activity in adult athletes. Caucasian and black athletes have been demonstrated to exhibit similar LA enlargement. The positive association of LA size with lean body mass (LBM) possibly accounts for the relationship of LA size with BSA. LA enlargement has been reported only in endurance‐trained, but not in strength‐trained athletes. LA size appears to increase with an increase in both the volume and intensity of endurance training. LA size correlates independently with the training age of endurance athletes. The athlete's characteristics that independently determine LA size include LBM, endurance training, and training age.

Athlete's Heart: Diagnostic Challenges and Future Perspectives

Distinguishing between adaptive and maladaptive cardiovascular response to exercise is crucial to prevent the unnecessary termination of an athlete's career and to minimize the risk of sudden death. This is a challenging task essentially due to the substantial phenotypic overlap between electrical and structural changes seen in the physiological athletic heart remodeling and pathological changes seen in inherited or acquired cardiomyopathies. Stress testing is an ideal tool to discriminate normal from abnormal cardiovascular response by unmasking subtle pathologic responses otherwise undetectable at rest. Treadmill or bicycle electrocardiography, transthoracic echocardiography, and cardiopulmonary exercise testing are common clinical investigations used in sports cardiology, specifically among participants presenting with resting electrocardiographic abnormalities, frequent premature ventricular beats, or non-sustained ventricular arrhythmias. In this setting, as well as in cases of left ventricular hypertrophy or asymptomatic left ventricular dysfunction, stress imaging and myocardial tissue characterization by cardiovascular magnetic resonance show promise. In this review, we aimed to reappraise current diagnostic schemes, screening strategies and novel approaches that may be used to distinguish adaptive remodeling patterns to physical exercise from early phenotypes of inherited or acquired pathological conditions commanding prompt intervention.

The Female Athlete's Heart: Comparison of Cardiac Changes Induced by Different Types of Exercise Training Using 3D Echocardiography

We aimed to characterize female athlete's heart in elite competitors in the International Federation of Bodybuilding and Fitness (IFBB) Bikini Fitness category and compare them to athletes of a more dynamic sport discipline and healthy, sedentary volunteers using 3D echocardiography. Fifteen elite female fitness athletes were recruited and compared to 15 elite, age-matched female water polo athletes and 15 age-matched healthy, nontrained controls. Using 3D echocardiography, left ventricular (LV) and right ventricular (RV) end-diastolic volume index (EDVi) and LV mass index (LVMi) were measured. Fitness athletes presented similar LV and RV EDVi compared to healthy, sedentary volunteers. Water polo athletes, however, had higher LV and also RV EDVi (fitness versus water polo versus control; LVEDVi: 76 ± 13 versus 84 ± 8 versus 73 ± 8 ml/m², ANOVA p = 0.045; RVEDVi: 61 ± 12 versus 86 ± 14 versus 55 ± 9 ml/m², p < 0.0001). LVMi was significantly higher in the athlete groups; the hypertrophy, however, was even more prominent in water polo athletes (78 ± 13 versus 91 ± 10 versus 57 ± 10 g/m², p < 0.0001). To the best of our knowledge, this is the first study to characterize female athlete's heart of IFBB Bikini Fitness competitors. The predominantly static exercise regime induced a mild, concentric-type LV hypertrophy, while in water polo athletes higher ventricular volumes and eccentric LV hypertrophy developed.