Sarah Charlesworth

Dilatation and Dysfunction of the Right Ventricle Immediately After Ultraendurance Exercise Exploratory Insights From Conventional Two-Dimensional and Speckle Tracking Echocardiography

Background— Running an ultramarathon has been shown to have a transient negative effect on right ventricular (RV) and left ventricular (LV) function. Additionally, recent findings suggested that ultraendurance athletes may be more at risk of developing a RV cardiomyopathy. The standard echocardiographic assessment of RV function is problematic; however, the introduction of ultrasonic speckle tracking technology has the potential to yield a comprehensive evaluation of RV longitudinal function, providing new insights into this phenomenon. Thus, the primary aim of this exploratory study was to evaluate comprehensively RV structure and function after a 161-km ultramarathon and establish whether changes in the RV are associated with alterations in LV function. Methods and Results— Myocardial speckle tracking echocardiograms of the RV and LV were obtained before and immediately after a 161-km ultramarathon in 16 healthy adults. Standard echocardiography was used to determine RV size and function and LV eccentricity index. Speckle tracking was used to determine the temporal evaluation of indices of RV and LV function. RV size was significantly increased postrace (RV outflow, 32 to 35 mm, P =0.002; RV inflow, 42 to 45 mm, P =0.027) with an increase in LV eccentricity index (1.03 to 1.13, P =0.006). RV strain (e) was significantly reduced postrace (−27% to −24%, P =0.004), but there was no change in the rates of e. Peak e in all planes of LV motion were reduced postrace (longitudinal, −18.3 to −16.3%, P =0.012; circumferential, −20.2% to −15.7%, P =0.001; radial, 53.4% to 40.3%, P =0.009). Changes in RV size and function correlated with diastolic strain rates in the LV. Conclusions— This exploratory study demonstrates RV dilatation and reduction in function after an ultramarathon. Further research is warranted to elucidate the mechanisms responsible for these findings. It is not clear what clinical impact might result from consecutive bouts of postexercise RV dysfunction.Background— Running an ultramarathon has been shown to have a transient negative effect on right ventricular (RV) and left ventricular (LV) function. Additionally, recent findings suggested that ultraendurance athletes may be more at risk of developing a RV cardiomyopathy. The standard echocardiographic assessment of RV function is problematic; however, the introduction of ultrasonic speckle tracking technology has the potential to yield a comprehensive evaluation of RV longitudinal function, providing new insights into this phenomenon. Thus, the primary aim of this exploratory study was to evaluate comprehensively RV structure and function after a 161-km ultramarathon and establish whether changes in the RV are associated with alterations in LV function. Methods and Results— Myocardial speckle tracking echocardiograms of the RV and LV were obtained before and immediately after a 161-km ultramarathon in 16 healthy adults. Standard echocardiography was used to determine RV size and function and LV eccentricity index. Speckle tracking was used to determine the temporal evaluation of indices of RV and LV function. RV size was significantly increased postrace (RV outflow, 32 to 35 mm, P=0.002; RV inflow, 42 to 45 mm, P=0.027) with an increase in LV eccentricity index (1.03 to 1.13, P=0.006). RV strain (&egr;) was significantly reduced postrace (−27% to −24%, P=0.004), but there was no change in the rates of &egr;. Peak &egr; in all planes of LV motion were reduced postrace (longitudinal, −18.3 to −16.3%, P=0.012; circumferential, −20.2% to −15.7%, P=0.001; radial, 53.4% to 40.3%, P=0.009). Changes in RV size and function correlated with diastolic strain rates in the LV. Conclusions— This exploratory study demonstrates RV dilatation and reduction in function after an ultramarathon. Further research is warranted to elucidate the mechanisms responsible for these findings. It is not clear what clinical impact might result from consecutive bouts of postexercise RV dysfunction.

Evidence-based risk assessment and recommendations for physical activity clearance: Consensus Document 2011 1

The Physical Activity Readiness Questionnaire (PAR-Q) and the Physical Activity Readiness Medical Evaluation (PARmed-X) are internationally known preparticipation screening tools developed on the basis of expert opinion. The primary purposes of this consensus document were to seek evidence-based support for the PAR-Q and PARmed-X forms, to identify whether further revisions of these instruments are warranted, to determine how people responding positively to questions on the PAR-Q can be safely cleared without medical referral, and to develop exercise clearance procedures appropriate for various clinical conditions across the human lifespan. Seven systematic reviews were conducted, examining physical-activity-related risks and effective risk-stratification procedures for various prevalent chronic conditions. An additional systematic review assessed the risks associated with exercise testing and training of the general population. Two gap areas were identified and evaluated systematically: the role of the qualified exercise professional and the requisite core competencies required by those working with various chronic conditions; and the risks associated with physical activity during pregnancy. The risks associated with being physically inactive are markedly higher than transient risks during and following an acute bout of exercise in both asymptomatic and symptomatic populations across the lifespan. Further refinements of the PAR-Q and the PARmed-X (including online versions of the forms) are required to address the unique limitations imposed by various chronic health conditions, and to allow the inclusion of individuals across their entire lifespan. A probing decision-tree process is proposed to assist in risk stratification and to reduce barriers to physical activity. Qualified exercise professionals will play an essential role in this revised physical activity clearance process.

Enhancing the effectiveness of clearance for physical activity participation: background and overall process.

Recent feedback from physical activity (PA) participants, fitness professionals, and physicians has indicated that there are limitations to the utility and effectiveness of the existing PAR-Q and PARmed-X screening tools for PA participation. The aim of this study was to have authorities in exercise and chronic disease management to work with an expert panel to increase the effectiveness of clearance for PA participation using an evidence-based consensus approach and the well-established Appraisal of Guidelines for Research and Evaluation (AGREE) Instrument. Systematic reviews were conducted to develop a new PA clearance protocol involving risk stratification and a decision-tree process. Evidence-based support was sought for enabling qualified exercise professionals to have a direct role in the PA participation clearance process. The PAR-Q+ was developed to use formalized probes to clarify problematic responses and to explore issues arising from currently diagnosed chronic disease or condition. The original PARmed-X tool is replaced with an interactive computer program (ePARmed-X+) to clear prospective PA participants for either unrestricted or supervised PA or to direct them to obtain medical clearance. Evidence-based validation was also provided for the direct role of highly qualified university-educated exercise professionals in the PA clearance process. The risks associated with exercise during pregnancy were also evaluated. The systematic review and consensus process, conforming to the AGREE Instrument, has provided a sound evidence base for enhanced effectiveness of the clearance process for PA participation of both asymptomatic populations and persons with chronic diseases or conditions.

Upper limits of physiological cardiac adaptation in ultramarathon runners.

To the Editor: Physiologic left ventricular (LV) hypertrophy is common in endurance-trained athletes ([1][1]). Controversially, a recent report from Japan suggested that a new upper limit for physiological LV hypertrophy might be present in ultramarathon runners ([2][2]). Specifically, in 291 male

Energy expenditure in the Race Across America (RAAM).

Energy Expenditure was measured with doubly labelled water technique during heavy sustained exercise with an official finishing team in the Race Across America. Energy Intake was also calculated to produce an energy balance for the race. A team of 4 cyclists (Mean +/-SD age: 37+4 yr; body height: 182+8 cm; body mass: 80.8+6.6 kg) completed the race in a relay fashion. The team completed the race in 6 days 10 h and 51 min. Total mean energy expenditure was found to be 43,401 kcals (181,711 kJ) with a mean daily energy expenditure of 6,420 kcals (26,879 kJ). Total mean energy intake from all food and drink consumed was calculated at 29,506 kcals (123,536 kJ) with a mean daily energy intake of 4 918 kcals (20,591 kJ). This resulted in a total mean energy deficit of 13,878 kcals (58,104 kJ) with a mean daily energy deficit of 1,503 kcals (6,293 kJ). The high energy expenditure highlights the need for correct and practical dietary strategies and challenges nutritionists to devise high energy diets that not only contain the correct macronutrient balance, but are also palatable to the cyclists, thus encouraging a high energy intake.

Systemic arterial compliance following ultra-marathon.

There is a growing interest in training for and competing in race distances that exceed the marathon; however, little is known regarding the vascular effects of participation in such prolonged events, which last multiple consecutive hours. There exists some evidence that cardiovascular function may be impaired following extreme prolonged exercise, but at present, only cardiac function has been specifically examined following exposure to this nature of exercise. The primary purpose of this study was to characterize the acute effects of participation in an ultra-marathon on resting systemic arterial compliance. Arterial compliance and various resting cardiovascular indices were collected at rest from 26 healthy ultra-marathon competitors using applanation tonometry (HDI CR-2000) before and after participation in a mountain trail running foot race ranging from 120-195 km which required between 20-40 continuous hours (31.2±6.8 h) to complete. There was no significant change in small artery compliance from baseline to post race follow-up (8.5±3.4-7.7±8.2 mL/mmHgx100, p=0.65), but large artery compliance decreased from 16.1±4.4 to 13.5±3.8 mL/mmHgx10 (p=0.003). Participation in extreme endurance exercise of prolonged duration was associated with acute reductions in large artery compliance, but the time course of this effect remains to be elucidated.

A segmental evaluation of arterial stiffness before and after prolonged strenuous exercise

We aimed to investigate the effects of a single session of prolonged strenuous exercise (PSE) on arterial stiffness by measuring pulse wave velocity (PWV) before and after competition in an ultramarathon. A total of 20 routine ultramarathon competitors (UM) completed baseline and postrace evaluation of central PWV (cPWV), upper-limb PWV (uPWV), and lower-limb PWV (lPWV) using carotid artery - femoral artery, carotid artery - finger, and femoral artery - toe segments, respectively. Fourteen additional age- and gender-matched normally active participants (NA) took part in the identical baseline evaluation but did not participate in the race. Average ultramarathon completion time was 30 h 47 min. Mean arterial blood pressure was reduced after exercise (before exercise (pre), 92 ± 7 mm Hg; after exercise (post), 84 ± 7 mm Hg; P < 0.001), whereas heart rate was increased (pre, 57 ± 10 beats·min(-1); post, 73 ± 12 beats·min(-1); P < 0.001). Also, lPWV (pre, 11.8 ± 3.6 m·s(-1); post, 9.6 ± 2.6 m·s(-1); P < 0.05) and uPWV (pre, 5.0 ± 0.53 m·s(-1); post, 4.4 ± 0.8 m·s(-1); P < 0.01) were reduced after exercise. No change in cPWV occurred (pre, 4.1 ± 0.8 m·s(-1); post, 3.9 ± 1.3 m·s(-1); P = 0.55). At baseline, the NA group had significantly increased cPWV in comparison with the UM group (UM, 4.1 ± 0.8 m·s(-1); NA, 7.4 ± 1.3 m·s(-1); P < 0.001). Acute participation in PSE influenced peripheral but not central arterial stiffness. Those who routinely participate in PSE have reduced central arterial stiffness as compared with normally active, age- and gender-matched controls.

A Unique Case Series of Novel Biomarkers of Cardiac Damage in Cyclists Completing the 4800 km Race Across America (RAAM)

Prolonged strenuous exercise is associated with the appearance of biomarkers of cardiac cell damage and a decline in cardiac function during recovery. Few studies have assessed repeated bouts of prolonged exercise and whether this results in further biomarker accumulation and greater dysfunction. Further, it may be useful to describe the changes in a range of biomarkers that may provide additional insight into the clinical significance of cardiac biomarker release. Four highly trained cyclists completed the 4800 km Race Across America (RAAM) in 7 days. Venous blood samples and echocardiograms were taken prior to, every 24 hours during and immediately after the RAAM. Venous blood was analysed for cardiac troponin I (cTnI), creatine kinase MB (CK-MB), fatty acid binding protein (HFABP), glycogen phosphorylase BB (GPBB) and N-Terminal Brain Natriuretic Peptide (NTproBNP). Echocardiograms allowed analysis of septal, left ventricular free wall and right ventricular free wall tissue velocities during systole and diastole. Before the RAAM cTnI levels were below the assay detection level (0.02 ng.ml⁻¹). In three riders cTnI peaked on day one (0.03 ng.ml⁻¹) and returned below detection levels post race. In the 4th rider cTnI peaked on day 5 (0.08 ng.ml⁻¹) and was still elevated post-race. Both CK-MB and H-FABP were increased during the RAAM in all 4 cyclists. In three riders H-FABP peaked on day one (3.49 to 5.09 ng.ml⁻¹) and declined over the rest of the RAAM. In the final rider H-FABP peaked on day two (5.90 ng.ml⁻¹) and then dropped back to baseline by the post-RAAM assessment. Interestingly, changes in H-FABP mirrored, temporally, changes in CK-MB in places and this may reflect an association with skeletal muscle damage. Data for GPBB value to (2.9 - 149.6 ng.ml⁻¹) and NTproBNP value to (27.3 - 310.0 ng.L⁻¹) were variable but again was elevated in all riders during the course of the RAAM. Changes in ventricular wall tissue velocities were minor and not cumulative. Peak atrial diastolic tissue velocity in the left ventricular free wall increased (P < 0.05) from 11 to 18 cm.s⁻¹ over the last two race days but this did not significantly impact the ratio of early to late diastolic wall motion. Cardiac biomarkers were elevated during the completion of the RAAM in all 4 cyclist but changes were not cumulative which suggest that the hearts of the cyclists coped well with the extreme cardiac work demanded by this ultra-endurance exercise challenge.

Characterisation of baroreflex sensitivity of recreational ultra-endurance athletes

Abstract Altered autonomic function has been identified following ultra-endurance event participation among elite world-class athletes. Despite dramatic increases in recreational athlete participation in these ultra-endurance events, the physiological effects on these athletes are less known. This investigation sought to characterise changes in surrogate measures of autonomic function: heart rate variability (HRV), blood pressure variability (BPV) and baroreceptor sensitivity (BRS) following ultra-endurance race participation. Further, we sought to compare baseline measures among ultra-endurance athletes and recreationally active controls not participating in the ultra-endurance race. Recreational ultra-endurance athletes (n = 25, 44.6 ± 8.2 years, 8 females) and recreationally active age, sex and body mass index matched controls (n = 25) were evaluated. Measurements of HRV, BPV and BRS were collected pre- and post-race for recreational ultra-endurance athletes and at baseline, for recreationally active controls. Post-race, ultra-endurance athletes demonstrated significantly greater sympathetic modulation [low frequency (LF) power HRV: 50.3 ± 21.6 normalised units (n.u.) to 65.9 ± 20.4 n.u., p = 0.01] and significantly lower parasympathetic modulation [high frequency (HF) power HRV: 45.0 ± 22.4 n.u. to 23.9 ± 13.1 n.u., p < 0.001] and BRS. Baseline measurements BRS (spectral: 13.96 ± 10.82 ms·mmHg−1 vs. 11.39 ± 5.33 ms·mmHg−1) were similar among recreational ultra-endurance athletes and recreationally active controls, though recreational ultra-endurance athletes demonstrated greater parasympathetic modulation of some HRV and BPV measures. Recreational ultra-endurance athletes experienced increased sympathetic tone and declines in BRS post-race, similar to previously reported elite world-class ultra-endurance athletes, though still within normal population ranges.

Sex differences in cardiac function after prolonged strenuous exercise.

Objective:To evaluate sex differences in left ventricular (LV) function after an ultramarathon, and the association of vascular and training indices with the magnitude of exercise-induced cardiac fatigue. Design:Descriptive field study. Setting:Fat Dog 100 Ultramarathon Trail Race, Canada. Participants:Thirty-four (13 women) recreational runners (aged 28-56 years). Interventions:A 100-km or 160-km mountain marathon. Main Outcome Measures:Baseline baroreceptor sensitivity, heart rate variability, and arterial compliance; Pre-exercise and postexercise echocardiographic evaluations of LV dimensions, volumes, Doppler flow velocities, tissue velocities, strain, and strain rate. Results:Finishers represented 17 men (44.8 ± 6.6 years) and 8 women (45.9 ± 10.2 years; P = 0.758). After ultraendurance exercise, significant reductions (P < 0.05) in fractional shortening (men: 40.9 ± 6.9 to 34.1 ± 7.6%; women: 42.5 ± 6.5 to 34.6 ± 7.9%) diastolic filling (E/A, men: 1.28 ± 0.68 to 1.26 ± 0.33; women: 1.55 ± 0.51 to 1.30 ± 0.27), septal and lateral tissue velocities (E′), and longitudinal strain (men: −21.02 ± 1.98 to −18.44 ± 0.34; women: −20.28 ± 1.90 to −18.44 ± 2.34) were observed. Sex differences were found for baseline cardiac structure and global function, peak late transmitral flow velocity, and estimates of LV filling pressures (P < 0.05). Regression analysis found that higher baseline arterial compliance was associated with lower reductions in cardiac function postexercise, to which sex was a significant factor for E′ of the lateral wall. Faster race pace and greater lifetime ultramarathons were associated with lower reductions in LV longitudinal strain (P < 0.05). Conclusions:Cardiac responses after an ultramarathon were similar between men and women. Greater evidence of exercise-induced cardiac fatigue was found to be associated with lower baseline arterial compliance and training status/experience. Clinical Relevance:These findings suggest that vascular health is an important contributor to the degree of cardiovascular strain incurred as the result of an acute bout of prolonged strenuous exercise.