Search

During pregnancy, assessment of cardiac output (𝑄̇), a fundamental measure of cardiovascular function, provides important insight into maternal adaptation. However, methods for dynamic 𝑄̇ measurement require validation. The purpose of this study was to estimate the agreement of 𝑄̇ measured by echocardiography and Modelflow® at rest and during submaximal exercise in non-pregnant (n = 18), pregnant (n = 15, 22-26 weeks gestation) and postpartum women (n = 12, 12-16 weeks post-delivery). Simultaneous measurements of 𝑄̇ derived from echocardiography [criterion] and Modelflow® were obtained at rest and during low-moderate intensity (25% and 50% peak power output) cycling exercise and compared using Bland-Altman analysis and limits of agreement. Agreement between echocardiography and Modelflow® was poor in non-pregnant, pregnant and postpartum women at rest (mean difference ± SD: -1.1 ± 3.4; -1.2 ± 2.9; -1.9 ± 3.2 L.min-1), and this remained evident during exercise. The Modelflow® method is not recommended for 𝑄̇ determination in research involving young, healthy non-pregnant and pregnant women at rest or during dynamic challenge. Previously published 𝑄̇ data from studies utilising this method should be interpreted with caution.

Supplemental Digital Content is available in the text., Serological assessment of cardiac troponins (cTn) is the gold standard to assess myocardial injury in clinical practice. A greater magnitude of acutely or chronically elevated cTn concentrations is associated with lower event-free survival in patients and the general population. Exercise training is known to improve cardiovascular function and promote longevity, but exercise can produce an acute rise in cTn concentrations, which may exceed the upper reference limit in a substantial number of individuals. Whether exercise-induced cTn elevations are attributable to a physiological or pathological response and if they are clinically relevant has been debated for decades. Thus far, exercise-induced cTn elevations have been viewed as the only benign form of cTn elevations. However, recent studies report intriguing findings that shed new light on the underlying mechanisms and clinical relevance of exercise-induced cTn elevations. We will review the biochemical characteristics of cTn assays, key factors determining the magnitude of postexercise cTn concentrations, the release kinetics, underlying mechanisms causing and contributing to exercise-induced cTn release, and the clinical relevance of exercise-induced cTn elevations. We will also explain the association with cardiac function, correlates with (subclinical) cardiovascular diseases and exercise-induced cTn elevations predictive value for future cardiovascular events. Last, we will provide recommendations for interpretation of these findings and provide direction for future research in this field.

PURPOSE: Pre-participation screening (PPS), using a 12-lead electrocardiogram (ECG), is recommended to identify athletes at risk of sudden cardiac death. ECG interpretation criteria have been developed to address the concern arising from high false-positives in athletes. There are limited ECG data in elite female footballers. The aims of this study were to 1) compare the ECG outcomes using three published ECG criteria (European Society of Cardiology [ESC], Seattle, International) in elite female footballers and 2) compare ECG data at three different stages of a competitive season. METHODS: Eighty-one elite female footballers (21±4 yr) completed a medical assessment, anthropometrics, resting blood pressure and a resting 12-lead ECG. Each 12-lead ECG was interpreted in accordance with 1) ESC; 2) Seattle; 3) International Criteria to determine training-related and non-training related ECG changes. A subset of thirteen (26±4 yr) footballers had repeated resting ECG tests at three time points across the competitive season. RESULTS: Eighty percent of females had training-related ECG patterns. Sinus bradycardia (65%) and early repolarization (42%) were the most common. Using the ESC Criteria 25% (20/81) of the athletes were considered to have an abnormal ECG, compared to 0% using the Seattle and International Criteria, mainly due to alterations in QT length criteria. There were no clinically significant differences in ECG data across a competitive season. CONCLUSION: The Seattle and International ECG Criteria significantly reduced the number of ECG false-positives in elite female footballers and the time point of PPS within a competitive season is unlikely to alter the PPS outcome.

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 (

OBJECTIVE To examine potential relationships between ECG characteristics and echocardiographic measures of cardiac structure in chimpanzees (Pan troglodytes). ANIMALS 341 chimpanzees (175 males and 166 females) from 5 sanctuaries and 2 zoological collections. PROCEDURES Chimpanzees were anesthetized for routine health examinations between May 2011 and July 2017 as part of the International Primate Heart Project and, during the same anesthetic events, underwent 12-lead ECG and transthoracic echocardiographic assessments. Relationships between results for ECG and those for echocardiographic measures of atrial areas, left ventricular internal diameter in diastole (LVIDd), and mean left ventricular wall thicknesses (MLVWT) were assessed with correlational analysis, then multiple linear regression analyses were used to create hierarchical models to predict cardiac structure from ECG findings. RESULTS Findings indicated correlations (r = −0.231 to 0.310) between results for ECG variables and echocardiographic measures. The duration and amplitude of P waves in lead II had the strongest correlations with atrial areas. The Sokolow-Lyon criteria, QRS-complex duration, and R-wave amplitude in leads V6 and II had the strongest correlations with MLVWT, whereas the Sokolow-Lyon criteria, QRS-complex duration, and S-wave amplitude in leads V2 and V1 had the strongest correlations with LVIDd. However, the ECG predictive models that were generated only accounted for 17%, 7%, 11%, and 8% of the variance in the right atrial end-systolic area, left atrial end-systolic area, MLVWT, and LVIDd, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that relationships existed between ECG findings and cardiac morphology in the chimpanzees of the present study; however, further research is required to examine whether the predictive models generated can be modified to improve their clinical utility.

Objective To evaluate left ventricular (LV) mechanics in the second trimester of healthy pregnancy and to determine the influence of underpinning hemodynamics (heart rate (HR), preload and afterload) on LV mechanics during gestation. Methods This was a cross-sectional study of 18 non-pregnant, 14 nulliparous pregnant (22-26 weeks' gestation) and 13 primiparous postpartum (12-16 weeks after delivery) women. All pregnant and postpartum women had uncomplicated, singleton gestations. Cardiac structure and function were assessed using echocardiography. LV mechanics, specifically longitudinal strain, circumferential strain and twist/untwist, were measured using speckle-tracking echocardiography. Differences between groups were identified using ANCOVA, with age, HR, end-diastolic volume (EDV) and systolic blood pressure (SBP) as covariates. Relationships between LV mechanics and hemodynamics were examined using Pearson's correlation. Results There were no significant differences in LV structure and traditional measurements of systolic and diastolic function between the three groups. Pregnant women, compared with non-pregnant ones, had significantly higher resting longitudinal strain (-22 ± 2% vs -17 ± 3%; P = 0.002) and basal circumferential strain (-23 ± 4% vs -16 ± 2%; P = 0.001). Apical circumferential strain and LV twist and untwist mechanics were similar between the three groups. No statistically significant relationships were observed between LV mechanics and HR, EDV or SBP within the groups. Conclusions Compared to the non-pregnant state, pregnant women in the second trimester of a healthy pregnancy have significantly greater resting systolic function, as assessed by LV longitudinal and circumferential strain. Contrary to previous work, these data show that healthy pregnant women should not exhibit reductions in resting systolic function between 22 and 26 weeks' gestation. The enhanced myocardial contractile function during gestation does not appear to be related to hemodynamic load and could be the result of other physiological adaptations to pregnancy. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Significance Unlike other great apes, humans evolved multisystem capabilities for moderate-intensity EPA, but it is unknown if selection acted similarly on the heart. We present data from a sample of humans, chimpanzees, and gorillas showing that the human (LV) evolved numerous features that help to augment stroke volume (SV), enabling moderate-intensity EPA. We also show that phenotypic plasticity of the human LV trades off pressure adaptations for volume capabilities, becoming more similar to a chimpanzee-like heart in response to physical inactivity or chronic pressure loading. Consequently, the derived human heart appears partly dependent upon moderate EPA and its absence, in combination with a highly processed diet, likely contributes to the modern epidemic of hypertensive heart disease., Chimpanzees and gorillas, when not inactive, engage primarily in short bursts of resistance physical activity (RPA), such as climbing and fighting, that creates pressure stress on the cardiovascular system. In contrast, to initially hunt and gather and later to farm, it is thought that preindustrial human survival was dependent on lifelong moderate-intensity endurance physical activity (EPA), which creates a cardiovascular volume stress. Although derived musculoskeletal and thermoregulatory adaptations for EPA in humans have been documented, it is unknown if selection acted similarly on the heart. To test this hypothesis, we compared left ventricular (LV) structure and function across semiwild sanctuary chimpanzees, gorillas, and a sample of humans exposed to markedly different physical activity patterns. We show the human LV possesses derived features that help augment cardiac output (CO) thereby enabling EPA. However, the human LV also demonstrates phenotypic plasticity and, hence, variability, across a wide range of habitual physical activity. We show that the human LV’s propensity to remodel differentially in response to chronic pressure or volume stimuli associated with intense RPA and EPA as well as physical inactivity represents an evolutionary trade-off with potential implications for contemporary cardiovascular health. Specifically, the human LV trades off pressure adaptations for volume capabilities and converges on a chimpanzee-like phenotype in response to physical inactivity or sustained pressure loading. Consequently, the derived LV and lifelong low blood pressure (BP) appear to be partly sustained by regular moderate-intensity EPA whose decline in postindustrial societies likely contributes to the modern epidemic of hypertensive heart disease.

Background: Clinical electrocardiographic (ECG) guidelines for athlete’s heart are based upon cross-sectional data. We aimed to longitudinally evaluate the influence of endurance training o...

NEW FINDINGS What is the central question of this study? Endurance athletes demonstrate altered regional right ventricular (RV) wall mechanics, characterized by lower basal deformation, in comparison to non-athletic control subjects at rest. We hypothesized that regional adaptations at the RV base reflect an enhanced functional reserve capacity in response to haemodynamic volume loading. What is the main finding and its importance? Free wall RV longitudinal strain is elevated in response to acute volume loading in both endurance athletes and control subjects. However, the RV basal segment longitudinal strain response to acute volume infusion is greater in endurance athletes. Our findings suggest that training-induced cardiac remodelling might involve region-specific adaptation in the RV functional response to volume manipulation. ABSTRACT Eccentric remodelling of the right ventricle (RV) in response to increased blood volume and repetitive haemodynamic load during endurance exercise is well established. Structural remodelling is accompanied by decreased deformation at the base of the RV free wall, which might reflect an enhanced functional reserve capacity in response to haemodynamic perturbation. Therefore, in this study we examined the impact of acute blood volume expansion on RV wall mechanics in 16 young endurance-trained men (aged 24 ± 3 years) and 13 non-athletic male control subjects (aged 27 ± 5 years). Conventional echocardiographic parameters and the longitudinal strain and strain rate were quantified at the basal and apical levels of the RV free wall. Measurements were obtained at rest and after 7 ml/kg i.v. Gelofusine infusion, with and without a passive leg raise. After infusion, blood volume increased by 12 ± 4 and 14 ± 5% in endurance-trained individuals versus control subjects, respectively (P = 0.264). Both endurance-trained individuals (8 ± 10%) and control subjects (7 ± 9%) experienced an increase in free wall strain from baseline, which was also similar following leg raise (7 ± 10 and 6 ± 10%, respectively; P = 0.464). However, infusion evoked a greater increase in basal longitudinal strain in endurance-trained versus control subjects (16 ± 14 vs. 6 ± 11%; P = 0.048), which persisted after leg raise (16 ± 18 vs. 3 ± 11%; P = 0.032). Apical longitudinal strain and RV free wall strain rates were not different between groups and remained unchanged after infusion across all segments. Endurance training results in a greater contribution of longitudinal myocardial deformation at the base of the RV in response to a haemodynamic volume challenge, which might reflect a greater region-specific functional reserve capacity.

With each heartbeat, the right ventricle (RV) inputs blood into the pulmonary vascular (PV) compartment, which conducts blood through the lungs at low pressure and concurrently fills the left atrium (LA) for output to the systemic circulation. This overall hemodynamic function of the integrated RV-PV-LA unit is determined by complex interactions between the components that vary over the cardiac cycle but are often assessed in terms of mean pressure and flow. Exercise challenges these hemodynamic interactions as cardiac filling increases, stroke volume augments, and cycle length decreases, with PV pressures ultimately increasing in association with cardiac output. Recent cardiopulmonary exercise hemodynamic studies have enriched the available data from healthy adults, yielded insight into the underlying mechanisms that modify the PV pressure-flow relationship, and better delineated the normal limits of healthy responses to exercise. This review will examine hemodynamic function of the RV-PV-LA unit using the two-element Windkessel model for the pulmonary circulation. It will focus on acute PV and LA responses that accommodate increased RV output during exercise, including PV recruitment and distension and LA reservoir expansion, and the integrated mean pressure-flow response to exercise in healthy adults. Finally, it will consider how these responses may be impacted by age-related remodeling and modified by sex-related cardiopulmonary differences. Studying the determinants and recognizing the normal limits of PV pressure-flow relations during exercise will improve our understanding of cardiopulmonary mechanisms that facilitate or limit exercise.

Measurements of intraocular pressure (IOP) and tear production are key components of ophthalmic examination. Chimpanzees (Pan troglodytes) were anesthetized using either tiletamine-zolazepam (TZ; 2 mg/kg) combined with medetomidine (TZM; 0.02 mg/kg), or, TZ alone (6mg/kg). Tear production was lower (P = 0.03) with TZM (5.63 ± 6.22 mm/min; n = 16) than with TZ (11.13 ± 4.63 mm/min; n = 8). Mean IOP, measured using rebound tonometry in an upright body position (n = 8) was 18.74 ± 3.01 mm Hg, with no differences between right and left eyes. However, positioning chimpanzees in left lateral recumbency (n = 27) resulted in higher IOP in the dependent (left) eye (24.77 ± 4.49 mm Hg) compared to the nondependent (right) eye (22.27 ± 4.65 mm Hg) of the same animal (P < 0.0001). These data indicate medetomidine anesthesia markedly lowers tear production in chimpanzees, and that body position should be taken into consideration when performing rebound tonometry.

We assessed the influence of barosensory vessel mechanics (magnitude and rate of unloading and time spent unloaded) as a surrogate for baroreceptor unloading. In young men, aortic unloading mechanics are important in regulating the operating point of the vascular sympathetic baroreflex, whereas in middle-aged men, these arterial mechanics do not influence this operating point. The age-related increase in resting muscle sympathetic nerve activity does not appear to be driven by altered baroreceptor input from stiffer barosensory vessels.

To examine potential relationships between ECG characteristics and echocardiographic measures of cardiac structure in chimpanzees (341 chimpanzees (175 males and 166 females) from 5 sanctuaries and 2 zoological collections.Chimpanzees were anesthetized for routine health examinations between May 2011 and July 2017 as part of the International Primate Heart Project and, during the same anesthetic events, underwent 12-lead ECG and transthoracic echocardiographic assessments. Relationships between results for ECG and those for echocardiographic measures of atrial areas, left ventricular internal diameter in diastole (LVIDd), and mean left ventricular wall thicknesses (MLVWT) were assessed with correlational analysis, then multiple linear regression analyses were used to create hierarchical models to predict cardiac structure from ECG findings.Findings indicated correlations (Results indicated that relationships existed between ECG findings and cardiac morphology in the chimpanzees of the present study; however, further research is required to examine whether the predictive models generated can be modified to improve their clinical utility.

KEY POINTS: We sought to determine the isolated and combined influence of hypovolaemia and hypoxic pulmonary vasoconstriction on the decrease in left ventricular (LV) function and maximal exercise capacity observed under hypobaric hypoxia. We performed echocardiography and maximal exercise tests at sea level (344 m), and following 5–10 days at the Barcroft Laboratory (3800 m; White Mountain, California) with and without (i) plasma volume expansion to sea level values and (ii) administration of the pulmonary vasodilatator sildenafil in a double‐blinded and placebo‐controlled trial. The high altitude‐induced reduction in LV filling and ejection was abolished by plasma volume expansion but to a lesser extent by sildenafil administration; however, neither intervention had a positive effect on maximal exercise capacity. Both hypovolaemia and hypoxic pulmonary vasoconstriction play a role in the reduction of LV filling at 3800 m, but the increase in LV filling does not influence exercise capacity at this moderate altitude. ABSTRACT: We aimed to determine the isolated and combined contribution of hypovolaemia and hypoxic pulmonary vasoconstriction in limiting left ventricular (LV) function and exercise capacity under chronic hypoxaemia at high altitude. In a double‐blinded, randomised and placebo‐controlled design, 12 healthy participants underwent echocardiography at rest and during submaximal exercise before completing a maximal test to exhaustion at sea level (SL; 344 m) and after 5–10 days at 3800 m. Plasma volume was normalised to SL values, and hypoxic pulmonary vasoconstriction was reversed by administration of sildenafil (50 mg) to create four unique experimental conditions that were compared with SL values: high altitude (HA), Plasma Volume Expansion (HA‐PVX), Sildenafil (HA‐SIL) and Plasma Volume Expansion with Sildenafil (HA‐PVX‐SIL). High altitude exposure reduced plasma volume by 11% (P

Measurements of intraocular pressure (IOP) and tear production are key components of ophthalmic examination. Chimpanzees (

To comprehensively characterize cardiac structure and function, from infancy to adulthood, in male and female wild-born captive chimpanzees (290 wild-born captive chimpanzees.Physical and echocardiographic examinations were performed on anesthetized chimpanzees in 3 sanctuaries in Africa between October 2013 and May 2017. Results were evaluated across age groups and between sexes, and potential differences were assessed with multiple 1-way independent Kruskal-Wallis tests.Results indicated that left ventricular diastolic and systolic function declined at a younger age in males than in females. Although differences in right ventricular diastolic function were not identified among age groups, right ventricular systolic function was lower in adult chimpanzees (12 years old), compared with subadult (8 to 12 years old) and juvenile (5 to 7 years old) chimpanzees. In addition, male subadult and adult chimpanzees had larger cardiac wall dimensions and chamber volumes than did their female counterparts.Results of the present study provided useful reference intervals for cardiac structure and function in captive chimpanzees categorized on the basis of age and sex; however, further research is warranted to examine isolated and combined impacts of blood pressure, age, body weight, and anesthetic agents on cardiac structure and function in chimpanzees.

This study focused on the influence of habitual endurance exercise training (i.e., committed runner or nonrunner) on the regulation of muscle sympathetic nerve activity (MSNA) and arterial pressure in middle-aged (50 to 63 yr, n = 23) and younger (19 to 30 yr; n = 23) normotensive men. Hemodynamic and neurophysiological assessments were performed at rest. Indices of vascular sympathetic baroreflex function were determined from the relationship between spontaneous changes in diastolic blood pressure (DBP) and MSNA. Large vessel arterial stiffness and left ventricular stroke volume also were measured. Paired comparisons were performed within each age category. Mean arterial pressure and basal MSNA bursts/min were not different between age-matched runners and nonrunners. However, MSNA bursts/100 heartbeats, an index of baroreflex regulation of MSNA (vascular sympathetic baroreflex operating point), was higher for middle-aged runners ( P = 0.006), whereas this was not different between young runners and nonrunners. The slope of the DBP-MSNA relationship (vascular sympathetic baroreflex gain) was not different between groups in either age category. Aortic pulse wave velocity was lower for runners of both age categories ( P < 0.03), although carotid β-stiffness was lower only for middle-aged runners ( P = 0.04). For runners of both age categories, stroke volume was larger, whereas heart rate was lower (both P < 0.01). In conclusion, we suggest that neural remodeling and upward setting of the vascular sympathetic baroreflex compensates for cardiovascular adaptations after many years committed to endurance exercise training, presumably to maintain arterial blood pressure stability. NEW & NOTEWORTHY Exercise training reduces muscle sympathetic burst activity in disease; this is often extrapolated to infer a similar effect in health. We demonstrate that burst frequency of middle-aged and younger men committed to endurance training is not different compared with age-matched casual exercisers. Notably, well-trained, middle-aged runners display similar arterial pressure but higher sympathetic burst occurrence than untrained peers. We suggest that homeostatic plasticity and upward setting of the vascular sympathetic baroreflex maintains arterial pressure stability following years of training.

In contrast to Andean natives, high-altitude Tibetans present with a lower hemoglobin concentration that correlates with reproductive success and exercise capacity. Decades of physiological and genomic research have assumed that the lower hemoglobin concentration in Himalayan natives results from a blunted erythropoietic response to hypoxia (i.e., no increase in total hemoglobin mass). In contrast, herein we test the hypothesis that the lower hemoglobin concentration is the result of greater plasma volume, rather than an absence of increased hemoglobin production. We assessed hemoglobin mass, plasma volume and blood volume in lowlanders at sea level, lowlanders acclimatized to high altitude, Himalayan Sherpa, and Andean Quechua, and explored the functional relevance of volumetric hematological measures to exercise capacity. Hemoglobin mass was highest in Andeans, but also was elevated in Sherpa compared with lowlanders. Sherpa demonstrated a larger plasma volume than Andeans, resulting in a comparable total blood volume at a lower hemoglobin concentration. Hemoglobin mass was positively related to exercise capacity in lowlanders at sea level and in Sherpa at high altitude, but not in Andean natives. Collectively, our findings demonstrate a unique adaptation in Sherpa that reorientates attention away from hemoglobin concentration and toward a paradigm where hemoglobin mass and plasma volume may represent phenotypes with adaptive significance at high altitude.

We are grateful for the interest and comments provided by Jensen and Wang (1) related to our recent paper (2). As previously noted, obtaining true resting blood pressure (BP) measurements in chimpanzees is challenging, if not impossible (1). In our study, and as described in detail in the SI Appendix of ref. 2, BP was measured at least three times in each animal, and the average of these measures was used for analysis (2). We specifically excluded measurements taken within the 20-min period immediately following anesthetic delivery, in order to minimize the effects of the stress associated with anesthetic induction and the initial hypertensive response … [↵][1]1To whom correspondence may be addressed. Email: rob.shave{at}ubc.ca. [1]: #xref-corresp-1-1

The influence of cardiorespiratory fitness (CRF) on arterial stiffness in young adults remains equivocal. Beyond conventional measures of arterial stiffness, 2D strain imaging of the common carotid artery (CCA) provides novel information related to the intrinsic properties of the arterial wall. Therefore, this study aimed to assess the effect of CRF on both conventional indices of CCA stiffness and 2D strain parameters, at rest and following a bout of aerobic exercise in young healthy males. Short‐axis ultrasound images of the CCA were recorded in 34 healthy men [22 years (95%CI, 19–22)] before, and immediately after 5‐minutes of aerobic exercise (40% VO2max). Images were analysed for arterial diameter, peak circumferential strain (PCS), and peak systolic and diastolic strain rates (S‐SR, D‐SR). Heart rate (HR), systolic and diastolic blood pressure (SBP, DBP) were simultaneously assessed and Petersons' elastic modulus (Ep) and Beta stiffness (β1) were calculated. Participants were separated post hoc into moderate and high fitness groups [VO2max: 48.9 ml.kg‐1 min‐1 (95%CI, 44.7–53.2) vs. 65.6 ml.kg‐1 min‐1 (95%CI, 63.1–68.1); P < 0.001]. Ep and β1 were similar between groups at baseline (P > 0.13) but were elevated in the moderate‐fitness group post‐exercise (P < 0.04). PCS and S‐SR were elevated in the high‐fitness group at both time‐points [3.0% (95%CI = 1.2, 4.9); P = 0.002; 0.401/s (95%CI = 0.085, 0.72); P = 0.02, respectively]. No group differences were observed in diameter, HR, SBP, DBP or D‐SR throughout the protocol (P > 0.05). High‐fit individuals exhibit elevated CCA PCS and S‐SR, which may reflect training‐induced adaptations that help to buffer the rise in pulse‐pressure and stroke volume during exercise.

> If exercise could be packed in a pill, it would be the single most widely prescribed and beneficial medicine in the nation. > > —Robert Butler, MD, Chair of the National Institute of Aging As captured by Robert Butler’s quote, there is no disputing the wide-reaching health benefits of exercise training. Despite this, the health burden associated with the diseases of inactivity continues to rise. Each year millions of dollars are invested to promote physical activity, yet uptake remains relatively low as highlighted by data showing that only 20.2% of the US population meet the physical activity guidelines for aerobic and muscle strengthening exercise.1 Given these facts, it is imperative that any research that questions the benefits of exercise, or indeed suggests that exercise is deleterious to health, needs to be handled responsibly and placed within appropriate context. See Article by Abdullah et al A logical question following on from Butler’s analogy is that if exercise acts as a medication, is it possible to overdose? This idea has received significant scientific attention, especially in relation …

Elite performance can require athletes to perform optimally in hypoxic conditions. Research findings show that exercising in hypoxia can produce a stress response, characterised by increased negative mood, and relatively poor performance. Recent research suggests that depressed mood is the most influential mood dimension (Lane and Terry, 2000), and that individuals reporting depressed mood tend also to report increased fatigue, confusion, anger, and tension and reduced vigour. PURPOSE: The purpose of the present study was to investigate mood changes during a two-hour cycling test during hypoxic and normoxic conditions. A second aim was to investigate mood dynamics that lead to depressed mood. METHODS: Eight male elite cyclists (Age: 26.23  6.74yrs; VO2max: 67.4  6.3 ml.kg-1.min-1) volunteered to participate in the study. Participants performed two 50-mile cycle bouts on a stationary cycle ergometer rig. Trials were randomly assigned from normobaric normoxia and normobaric hypoxia (FIO2 ≈15.3%, a simulated altitude of 2,500 metres), and were separated by two weeks. Both cycle bouts were performed at an intensity equivalent to lactate threshold (previously determined in normobaric normoxia). Mood was assessed before, after one hour, after two hours and on completion of the 50 mile ride using the 24-item Brunel Mood Scale (Terry, Lane, Lane, & Keohane, 1999), which assesses anger, confusion, depression, fatigue, tension, and vigor. RESULTS: Repeated measures ANOVA (time x condition) results showed that fatigue increased significantly more at altitude than at sea level (F 1,7 = 5.73, p < .05, Eta2 = .45). Other unpleasant mood states also increased more during the hypoxic condition than the normoxic condition. Effects were moderate, although not statistically significant, for anger (F 1,7 = 3.87, p = .09, Eta2 =.36), confusion (F 1,7 = 2.21, p = .18, Eta2 =.24), depression (F 1,7 = 2.88, p = .13, Eta2 =.29), and tension (F 1,7 = 3.09, p = .12, Eta2 = .31). Vigor scores decreased more during the altitude ride (F 1,7 = 2.26, p = .18, Eta2 = .25). An examination of mood dynamics indicated that increases in depressed mood followed an exponential increase in fatigue, rather than the other way around, and that once depressed mood was activated it was associated with increased anger, confusion, and tension and reduced vigor. CONCLUSIONS: Findings lend support to the notion that, compared to sea level, performing intense exercise at altitude is associated with greater mood disturbance. It is suggested that future research investigates the post-exercise duration of such mood disturbance and the interplay between mood dynamics and the type of coping strategies used by athletes during intense exercise.